[Drakelist] T-4xc sidetone problem
good evening I have a problem with my t-4XC. The sidetone works, but beyond my cw note, you will hear a whistle or other note This whistle disappears if I delete ANTIVOX cable, and listening to me through the R4C my note is always pure and clean in the air. So it's a local problem sidetone. I tried to replace the 12AX7 and 6ev7 that are part of the circuit sidetone, vox etc.. etc., but I did not get any change. Some amateur has had similar problems? many thanks ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4xc sidetone problem
replaced C-107 with a 250VDC 47mfd electrolytic. Tom W9QI -Original Message- From: Paolo Emanuelli IK1QHB [mailto:ik1...@fastwebnet.it] Sent: Sunday, October 13, 2013 11:29 AM To: drakelist@zerobeat.net Subject: [Drakelist] T-4xc sidetone problem good evening I have a problem with my t-4XC. The sidetone works, but beyond my cw note, you will hear a whistle or other note This whistle disappears if I delete ANTIVOX cable, and listening to me through the R4C my note is always pure and clean in the air. So it's a local problem sidetone. I tried to replace the 12AX7 and 6ev7 that are part of the circuit sidetone, vox etc.. etc., but I did not get any change. Some amateur has had similar problems? many thanks ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC
Update: With everyone's advice I looked into what freq the transmitter was really on. I found the crystal wafer switch off position and really thought that was my issue, not. I also found no matter where the transceive switch was, it always uses the injection VFO from the R-4C. Of course with the Saints game on yesterday, I didn't spend a whole lot of time after aligning the shaft and making a few tests.thanks all,manny- wd5bjr -Original Message- From: Glen Kirkpatrick w...@leosatinc.com Sent 9/15/2013 10:19:17 AM To: Manny Miyares ma...@catcomm.net Subject: Re: [Drakelist] T-4XCHi Manny, You may have resolved this offline already. I'm not exactly sure how the Drake reflector works these days after they went to the web-based format (It's hard when you're an old guy...). Anyway, you may have checked this, but it sounds like there could be a problem with the port on the MFJ multiport switch that the T-4XC is connected to. Try swapping ports with one of the other rigs and see if the problem follows the rig or the port. What is the sequence of equipment connections? It sounds like transmitter, switch, MN-2000, amplifier, SWR/power meter and antenna. This is probably unrelated, but it might be better to put the matching network between the SWR meter and antenna. The logic is that the transmitter output pi network should have no problem matching the amplifier input impedance, but the amplifier may or may not be able to match the antenna impedance. If you put the MN-2000 between the amp and the antenna, both the transmitter and amplifier are looking into 50 ohms. That way when you switch between amplifier in-line and bypassed, nothing needs to be retuned. Please let me know what you find. I've been running the same T-4XC since 1978 (it was used when I got it). Still works! GL 73, Glen - W9LSFrom: Manny Miyares ma...@catcomm.netTo: drakelist@zerobeat.net Sent: Saturday, September 14, 2013 4:26 PMSubject: [Drakelist] T-4XCHi Guys, I'm just back into radio this year and find myself gravitating to the older gear. I have several C pieces along with an L-4B (have to have one of these). I bought several broken and find a bad resistor or tube through most, however I have a T-4XC that's giving be problems. I can tune up into a dummy load fine, however on the G5RV SWR is through the roof. Keep in mind I have an MJF Multi Port Antenna switch and have my MFJ Antenna Analyzer on a transmitter port and switch to it to match the antenna through my MN-2000 which feeds into my amp and meter. I can get a 1:1 match through the antenna tuner with the Analyzer, flip to one of two radios, my TR-4C, and 4Cw and keep the low SWR. Even my Yaesu FT-897D is happy with this configuration. When I switch to the T-4XC the SWR jumps to 5+ to 1!!! (Yes, I've checked the patch cables) Holy Smokes Batman!!! So into a dummy load it's happy, but when I move to a matched antenna it goes nuts. I can't even match the T-4XC direct using the tuner and way off where the analyzer first tuned the antenna.Any pointers would be greatly appreciated.Thanks guys, manny- wd5bjr ___ Drakelist mailing listDrakelist@zerobeat.nethttp://mailman.zerobeat.net/mailman/listinfo/drakelist___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC
On Sep 16, 2013, at 9:00 AM, drakelist-requ...@zerobeat.net wrote: With everyone's advice I looked into what freq the transmitter was really on. I found the crystal wafer switch off position and really thought that was my issue, not. I also found no matter where the transceive switch was, it always uses the injection VFO from the R-4C. Of course with the Saints game on yesterday, I didn't spend a whole lot of time after aligning the shaft and making a few tests.thanks all,manny- This situation reminded me of a problem I had with a TR4 many years ago when I attached a remote VFO. The internal TR4 VFO would not turn off when the remote VFO was activated, both VFO's were running. I checked the remote VFO on another TR4 and it worked properly. Examining carefully the printed circuit board in the TR4 VFO I found a solder bridge between two tracks. Removing that bridge cured the problem and it worked correctly after the bridge removal. Harold N3HP ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC
Hi Manny: Are you sure that when you are transmitting into the Dummy load that the output is on the frequency you think? Check it. The dummy load will happily load the Tx on ANY freq it puts out...the tuned antenna only one or two places--so if the output is mixing improperly and off freq, it wont load properly. Put a scope on the output or a freq counter or a general coverage Rx while on the Dummy load. FWIW Curt KU8L On 9/14/2013 7:26 PM, Manny Miyares wrote: Hi Guys, I'm just back into radio this year and find myself gravitating to the older gear. I have several C pieces along with an L-4B (have to have one of these). I bought several broken and find a bad resistor or tube through most, however I have a T-4XC that's giving be problems. I can tune up into a dummy load fine, however on the G5RV SWR is through the roof. Keep in mind I have an MJF Multi Port Antenna switch and have my MFJ Antenna Analyzer on a transmitter port and switch to it to match the antenna through my MN-2000 which feeds into my amp and meter. I can get a 1:1 match through the antenna tuner with the Analyzer, flip to one of two radios, my TR-4C, and 4Cw and keep the low SWR. Even my Yaesu FT-897D is happy with this configuration. When I switch to the T-4XC the SWR jumps to 5+ to 1!!! (Yes, I've checked the patch cables) Holy Smokes Batman!!! So into a dummy load it's happy, but when I move to a matched antenna it goes nuts. I can't even match the T-4XC direct using the tuner and way off where the analyzer first tuned the antenna. Any pointers would be greatly appreciated. Thanks guys, manny- wd5bjr ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC
Hi Guys, I'm just back into radio this year and find myself gravitating to the older gear. I have several C pieces along with an L-4B (have to have one of these). I bought several broken and find a bad resistor or tube through most, however I have a T-4XC that's giving be problems. I can tune up into a dummy load fine, however on the G5RV SWR is through the roof. Keep in mind I have an MJF Multi Port Antenna switch and have my MFJ Antenna Analyzer on a transmitter port and switch to it to match the antenna through my MN-2000 which feeds into my amp and meter. I can get a 1:1 match through the antenna tuner with the Analyzer, flip to one of two radios, my TR-4C, and 4Cw and keep the low SWR. Even my Yaesu FT-897D is happy with this configuration. When I switch to the T-4XC the SWR jumps to 5+ to 1!!! (Yes, I've checked the patch cables) Holy Smokes Batman!!! So into a dummy load it's happy, but when I move to a matched antenna it goes nuts. I can't even match the T-4XC direct using the tuner and way off where the analyzer first tuned the antenna.Any pointers would be greatly appreciated.Thanks guys, manny- wd5bjr___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Transmitter Woes
I have a Drake T-4XC transmitter with full output on 40 meters and zero output on all the other bands. Anyone have any suggestions on where to start troubleshooting this problem? Any suggestions would be greatly appreciated. Thanks Rod N4BNO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC and AL-811 Amp
Hi Gang, What is the best way to key a AL-811 amp with a T-4XC? The amp requires an external ground to key. Tnx for any suggestions, 73, AL WA9IWS___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC and AL-811 Amp
The VOX RELAY jack on the AC-4 73, Gary http://home.roadrunner.com/~w8pu R-4A T4-X R-4B T4-XB R-4C T4-XC MS-4 L-4B RCS-4 2A 2B 2C 2NT 2CQ 2AS 4-LF TR-4 TR-4C TR-4CW/RIT RV-4C MC-4 TR-7 RV-7 CW-75 MS-7 WH-7 W-4 WV-4 MN-2700 MN-4C MN-2000 UV-3 PS-3 TR-22C TR-33C AA-10 AC-10 MMK-22 TR-6 PRN1000 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC and AL-811 Amp
Hi Al, Agree with Gary, There is a company that makes the small connector for the AC4 application, just surf T-4-XC sites. Looks like an old small xtal connector. Cheap, a few dollars. Tnx, Bob W3QJ On Mon, Feb 11, 2013 at 3:12 PM, astu...@cox.net wrote: ** Hi Gang, What is the best way to key a AL-811 amp with a T-4XC? The amp requires an external ground to key. Tnx for any suggestions, 73, AL WA9IWS ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC loss of bias
T-4XC recently refurbed by pro. Was working like new. Suddenly cannot load on any band over about 10 watts out. Plate current limits out at 100 mils+/-. thought it was PS, changed to different AC-4, same results. Swapped finals and driver tubes. Same result. Looking for pointers on where to start my search. Think a component in the PA has failed. Have not started diagnosis. Will be doing resistance and voltage checks per manual. Any and All ideas accepted! 73, Wayne k5FEX ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] t-4xc help…all is ok now!
Thanks folks The problem was low power on 15m band (80w) and heavy difference between separate rcvr xmtr mode (more low power (60-70w)... Have tuned the RF trimmer on the left side of the chassis... and now the power is more or less 130w on every position and exactly the same...130w I'm very very happy! Next step forced air with fan for the final tubes... Paul IK1QHB ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] t-4xc HELP!!!
HI folks I've in the shack now a wonderful T-4XC totally restored...by me. After a week of work on the chassis all seems to be ok ...there's only a problem on 15m band. On every band the power is ok (150w on 80m since 120w in 10m) but on 15 meter not more than 85w on separate, 50w on rcvr and 65 on xmtr mode... The band switch is ok after a hard work and a bit of patience! I'm waiting for a deoxit d100 from USA, but i'm not sure the problem is on the band switch or on the transceive switch... it could be some other problem of RF tune stage? On other band i was able to obtain same power both separate and rcvr/xmtr... (never been before restoration of the bands witch). Can somebody help me to obtain full power also on 15m band? Many thanks Paul IK1QHB Please Reply also at : ik1...@fastwebnet.it ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC T/R relay
I recently acquired a parts unit T4XClooks to good to be a parts rig so I am going to make an attempt at saving it. Somewhere along the line someone hijacked the T/R relay. Is the relay for a TR7 the same relay,or is it a different part number? I have one in the junkbox,but want to make certain before I plug it in possibly smoke something in the T4XC by putting in wrong relay Thanks Paul ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC T/R relay
Paul - I don't think they're interchangeable, but I'm somewhat surprised that I can't find any information about the relay in either the T-4X manual or Garey's CD. I might just be tired. The coil of that relay goes from the +250V supply to plate of the VOX control tube V10. It may need to drop a fair amount of voltage across that coil. I've also heard of some folks modifying the circuit so that they can use a relay with a lower-voltage coil. 73, Steve Wedge, W1ES/4 Live free or die: Death is not the worst of evils. John Stark. All my computers have my signature with various pearls of wisdom appended thereto. -- From: Paul draked...@comcast.net Sent: Sunday, April 01, 2012 5:18 PM To: drakel...@.zerobeat.net drakelist@zerobeat.net Subject: [Drakelist] T-4XC T/R relay I recently acquired a parts unit T4XClooks to good to be a parts rig so I am going to make an attempt at saving it. Somewhere along the line someone hijacked the T/R relay. Is the relay for a TR7 the same relay,or is it a different part number? I have one in the junkbox,but want to make certain before I plug it in possibly smoke something in the T4XC by putting in wrong relay Thanks Paul ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC T/R relay
Hi Paul, Garey must have gone out for a long supper. Here's what he said about 5 yrs ago: GAREY - K4OAH k4...@mindspring.com made an utterance to the drakelist gang -- Check your old relay. If it is a 15k ohm coil, you'll need to add a 1.5k, 1/2W resistor in series with the coil to replace it with the PB R10-E1Y4-V2.5K relay available from Mouser, Digi-Key and others. The 15k relays were unreliable because of the very fine wire required to get the high impedance. The wire broke either at the terminals from corrosion or inside the coil from temperature excursions. The replacement is very reliable. 73, Garey - K4OAH Atlanta Drake 2-B, 4B C Service Supplement CDs www.k4oah.com -- Since you don't have your old relay, maybe you should add a 15k res. see if it works. But maybe with your T-4XC it's late enough that the replacement would have gone in at the factory. Butt -- Garey's old response did have T-4XC in the subject. 73, Al, W8UT www.boatanchors.org www.hammarlund.info There is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats Ratty, to Mole ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC T/R relay
Paul, Al and others - The resistor is a 1.5k, (1W is better). I don't know when Drake specifically changed over, but if your T-4XC doesn't already have the resistor between Pins 6 and 9 of V10, you need to add it. See attached sheet from the CD. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Al Parker wrote: Hi Paul, Garey must have gone out for a long supper. Here's what he said about 5 yrs ago: GAREY - K4OAH k4...@mindspring.com made an utterance to the drakelist gang -- Check your old relay. If it is a 15k ohm coil, you'll need to add a 1.5k, 1/2W resistor in series with the coil to replace it with the PB R10-E1Y4-V2.5K relay available from Mouser, Digi-Key and others. The 15k relays were unreliable because of the very fine wire required to get the high impedance. The wire broke either at the terminals from corrosion or inside the coil from temperature excursions. The replacement is very reliable. 73, Garey - K4OAH Atlanta -- Since you don't have your old relay, maybe you should add a 15k res. see if it works. But maybe with your T-4XC it's late enough that the replacement would have gone in at the factory. Butt -- Garey's old response did have T-4XC in the subject. T-4XC Relay Replacement.pdf Description: acrobat/pdf ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC alignment question
OK, decided today to align my T-4XC. According to the manual, RF Mixer stage trimmer alignment sectionthe T5 T4 need to be de-tuned before peaking the front 2 trimmers. Is this really neccessary? or can I just peak for max drive on all trimmers?? If I remmeber correctly that is what I did before with good success. Thanks, 73, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4Xc alignment...another ?
OK, discovered something else...looks like Drake aligned the tuning rack based on a RED DOT coils form set. The brown glyptol is intact. But, My coils do not have any dots on them...did they go away? Or did Drake change the way they did this? I really don't want to touch them as they are all the same.and with pre-selector far CCW on 0...they are at 39/64 (RED DOT setting??) Thanks, 73, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4Xc alignment...another ?
Lee - I assume you mean 3/64. It's also possible that someone has been 'fixing' the pointer adjustment too!! I would NOT change anything and just go with where they are. I've seen them with 'red' on the top of the core and on the bottom of the core. I don't know what criteria were involved to make them a red dot or ... Possibly core lots? If it tunes up ok I wouldn't worry about it. Only thing I can think of would be an inability to reach the high end of 10M, or the low end of 160M. I have had to fudge a bit on 10m to avoid having the trimmer adjuster screw fall out! Suggest you put a drop of nail polish on the 10M screws, or they might change when you turn the radio on its' side! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com kc9...@aol.com wrote: OK, discovered something else...looks like Drake aligned the tuning rack based on a RED DOT coils form set. The brown glyptol is intact. But, My coils do not have any dots on them...did they go away? Or did Drake change the way they did this? I really don't want to touch them as they are all the same.and with pre-selector far CCW on 0...they are at 39/64 (RED DOT setting??) Thanks, 73, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
Hi Guys, I have good news to report. I have the PTO back in the T-4XC and it is working fine. It turned out to be the hardened grease in the PTO ball bearings causing the chirp and warbling after all. It didn't seem to be a plausible cause to me for the symptoms I was experiencing. But before I started changing parts out, I decided to clean the ball bearings and the drive screw and it did the trick. AS for the PTO not working after I reinstalled it into the transmitter, it turned out to be an intermitant connection on the center tap of the PTO coil. Gary told me to check it. Visually it looked OK, but when I pressed on the connection, the oscillator came alive on the scope screen. Gary is amazing he can repair radios from thousands of miles away. So I cleaned up the connection and reflowed it. It is back in the T-4XC and working great now. In fact, right after I got everything back together I heard ZK2V on 10 meters running split. A perfect opportunity to test the Transmitter PTO. He was calling for just EU for a while, but when he asked for USA I started calling 3kc up. I got him on the 3rd or 4th call. That's a new one for me. Niue, I think it is an island down in the south Pacific somewhere. Not very difficult for me on the west coast but, stil a good test for the PTO. This was only 15 or 20 minutes ago, he is still there on 28011 if your interested. Anyway that's the end of this adventure. You guys will hear from me again next time I break something. 73, Bob K6GGO Hi Guys, Here is an update on my T-4XC PTO adventure. I eventually removed the PTO from the transmitter and put it in a panavise on my bench, powered it up and listened to it on my TR-7 with a sniffer wire. While monitoring the tone, I tapped on the rod that carries the ferrite slug. It would make the frequency change and stay on the new frequency every time I tapped it. As an experiment, I opened up the R-4C and tapped on the end of the slug shaft on it. On the R-4C, the frequency would change but always return to the original freq. To make a long story short, I found hardened grease in the ball bearing races. I cleaned the ball bearings, races and the drive screw with denatured alcohol. The frequency returns to the same tone now every time I tap it and the warbling is gone when I turn the knob. I was and am convinced I fixed the problem. Here is the part where Murphy rears his ugly head. I put the PTO back together and reinstalled it in the T-4XC and presto!!what? dead silence. I used the PTO to control the R-4C still dead silence. I checked power and ground it looks fine but still, nary an oscillation from the PTO. So I unsoldered the wires and hauled it's sorry a?!%#$ back onto the bench. Powered it up and still nothing. Obviously, I hosed it somehow during the re-install. I looked for a solder problem around the output terminal it looked ok, but there were a couple of strands of wire from the old connection that the solder sucker (me) missed, but they weren't touching anything. Maybe they were touching something when it was installed, I don't know. At any rate, its dead now and I suspect a semiconductor. here are my questions: (about time eh?) I have the diodes in stock but not the FET or the buffer transistor. If I have to make a Digikey (or Mouser) order anyway, maybe I should just shot gun the thing and put in all new parts except the coils. I also have a PTO from a parts rig that has issues. I would like to rebuild it as well. Will I get into problems with tolerance stackups? I suspect that is why there are select at test caps in there. Can I replace the coax that goes from the PTO output to the wafer switch with RG-174? (to give myself a small service loop, to make the re-install easier) If it turns out to be a cap, or if I shotgun it, is there a modern replacement for those horseshoe caps? Is there anything special about the temperature compensating caps, like a backwards temp coefficient for bucking freq drift or something? Is there an easy replacement for those? Sorry for the long post about my epic struggle against the evil Murphy. If the 49ers hadn't won, it truly would have been a lost weekend. Thanks as always, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
I sometimes have to remind myself: Occam's Razor is my friend. Steve Wedge, W1ES/4 To be is to do - Socrates To do is to be - Plato Do be do be do. - Sinatra All my computers have my signature with various pearls of wisdom appended thereto. From: Robert Fish Sent: Tuesday, November 01, 2011 3:22 PM To: Drakelist@zerobeat.net Subject: Re: [Drakelist] T-4XC PTO chirps Hi Guys, I have good news to report. I have the PTO back in the T-4XC and it is working fine. It turned out to be the hardened grease in the PTO ball bearings causing the chirp and warbling after all. It didn't seem to be a plausible cause to me for the symptoms I was experiencing. But before I started changing parts out, I decided to clean the ball bearings and the drive screw and it did the trick. AS for the PTO not working after I reinstalled it into the transmitter, it turned out to be an intermitant connection on the center tap of the PTO coil. Gary told me to check it. Visually it looked OK, but when I pressed on the connection, the oscillator came alive on the scope screen. Gary is amazing he can repair radios from thousands of miles away. So I cleaned up the connection and reflowed it. It is back in the T-4XC and working great now. In fact, right after I got everything back together I heard ZK2V on 10 meters running split. A perfect opportunity to test the Transmitter PTO. He was calling for just EU for a while, but when he asked for USA I started calling 3kc up. I got him on the 3rd or 4th call. That's a new one for me. Niue, I think it is an island down in the south Pacific somewhere. Not very difficult for me on the west coast but, stil a good test for the PTO. This was only 15 or 20 minutes ago, he is still there on 28011 if your interested. Anyway that's the end of this adventure. You guys will hear from me again next time I break something. 73, Bob K6GGO Hi Guys, Here is an update on my T-4XC PTO adventure. I eventually removed the PTO from the transmitter and put it in a panavise on my bench, powered it up and listened to it on my TR-7 with a sniffer wire. While monitoring the tone, I tapped on the rod that carries the ferrite slug. It would make the frequency change and stay on the new frequency every time I tapped it. As an experiment, I opened up the R-4C and tapped on the end of the slug shaft on it. On the R-4C, the frequency would change but always return to the original freq. To make a long story short, I found hardened grease in the ball bearing races. I cleaned the ball bearings, races and the drive screw with denatured alcohol. The frequency returns to the same tone now every time I tap it and the warbling is gone when I turn the knob. I was and am convinced I fixed the problem. Here is the part where Murphy rears his ugly head. I put the PTO back together and reinstalled it in the T-4XC and presto!!what? dead silence. I used the PTO to control the R-4C still dead silence. I checked power and ground it looks fine but still, nary an oscillation from the PTO. So I unsoldered the wires and hauled it's sorry a?!%#$ back onto the bench. Powered it up and still nothing. Obviously, I hosed it somehow during the re-install. I looked for a solder problem around the output terminal it looked ok, but there were a couple of strands of wire from the old connection that the solder sucker (me) missed, but they weren't touching anything. Maybe they were touching something when it was installed, I don't know. At any rate, its dead now and I suspect a semiconductor. here are my questions: (about time eh?) I have the diodes in stock but not the FET or the buffer transistor. If I have to make a Digikey (or Mouser) order anyway, maybe I should just shot gun the thing and put in all new parts except the coils. I also have a PTO from a parts rig that has issues. I would like to rebuild it as well. Will I get into problems with tolerance stackups? I suspect that is why there are select at test caps in there. Can I replace the coax that goes from the PTO output to the wafer switch with RG-174? (to give myself a small service loop, to make the re-install easier) If it turns out to be a cap, or if I shotgun it, is there a modern replacement for those horseshoe caps? Is there anything special about the temperature compensating caps, like a backwards temp coefficient for bucking freq drift or something? Is there an easy replacement for those? Sorry for the long post about my epic struggle against the evil Murphy. If the 49ers hadn't won, it truly would have been a lost weekend. Thanks as always, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist
Re: [Drakelist] T-4XC PTO chirps
I meant Dogbone caps, not horseshoe. Sheesh. Hi Guys, Here is an update on my T-4XC PTO adventure. I eventually removed the PTO from the transmitter and put it in a panavise on my bench, powered it up and listened to it on my TR-7 with a sniffer wire. While monitoring the tone, I tapped on the rod that carries the ferrite slug. It would make the frequency change and stay on the new frequency every time I tapped it. As an experiment, I opened up the R-4C and tapped on the end of the slug shaft on it. On the R-4C, the frequency would change but always return to the original freq. To make a long story short, I found hardened grease in the ball bearing races. I cleaned the ball bearings, races and the drive screw with denatured alcohol. The frequency returns to the same tone now every time I tap it and the warbling is gone when I turn the knob. I was and am convinced I fixed the problem. Here is the part where Murphy rears his ugly head. I put the PTO back together and reinstalled it in the T-4XC and presto!!what? dead silence. I used the PTO to control the R-4C still dead silence. I checked power and ground it looks fine but still, nary an oscillation from the PTO. So I unsoldered the wires and hauled it's sorry a?!%#$ back onto the bench. Powered it up and still nothing. Obviously, I hosed it somehow during the re-install. I looked for a solder problem around the output terminal it looked ok, but there were a couple of strands of wire from the old connection that the solder sucker (me) missed, but they weren't touching anything. Maybe they were touching something when it was installed, I don't know. At any rate, its dead now and I suspect a semiconductor. here are my questions: (about time eh?) I have the diodes in stock but not the FET or the buffer transistor. If I have to make a Digikey (or Mouser) order anyway, maybe I should just shot gun the thing and put in all new parts except the coils. I also have a PTO from a parts rig that has issues. I would like to rebuild it as well. Will I get into problems with tolerance stackups? I suspect that is why there are select at test caps in there. Can I replace the coax that goes from the PTO output to the wafer switch with RG-174? (to give myself a small service loop, to make the re-install easier) If it turns out to be a cap, or if I shotgun it, is there a modern replacement for those horseshoe caps? Is there anything special about the temperature compensating caps, like a backwards temp coefficient for bucking freq drift or something? Is there an easy replacement for those? Sorry for the long post about my epic struggle against the evil Murphy. If the 49ers hadn't won, it truly would have been a lost weekend. Thanks as always, Bob K6GGO Garey, Eddy, Paul, Curt and Steve, Thanks for the quick replies guys. This is a great bunch on this list. I am convinced that it is the PTO. If I lightly tap on the PTO can with a pencil tip (and I mean very lightly) it causes the signal to jump around. Maybe just a cold solder joint. I have a parts radio (T-4XC) with a PTO in it. I guess I'll haul it out and test it. If it's stable, I will swap it with the faulty one. Can I then rebuild (shotgun) the bad PTO with all new parts? or is there special parts in there that I have to be careful with? I probably have most of the stuff in stock (NPO caps, metal film resistors etc.). It would be handy to have a nice new spare because I also have a B-Line. Also, A 5Mhz PTO is a nice thing to have around, homebrew QRP rigs etc. I have a HP signal generator, so I think I will try Paul's suggestion on the Lissajous display. Perhaps I can find the faulty component with some freeze spray and make this a quick repair. Maybe learn something in the process (heaven forbid). I wrote this e-mail in three sittings as real life keeps intervening. The bottom line is, thanks for all the help, I will let you know how I proceed and the results thereof. 73, Bob K6GGO On 2011-10-26, at 1:16 PM, Steve Wedge wrote: Removing the PTO - at least with the A's and B's - requires removal of the front panel. This is a good time to clean it as well as the fiducial window. Use only dish soap for the window or you'll take off the red line! */ /* */Hi Guys,/* Well, I can not vouch for the A B series, but in my T-4X transmitter /that/extensive a dis-aasembly is most assuredly */NOT/*required... After removing the three tubes immediately behind the PTO can, the can itself is extricated by first dis-connecting the top grounding spring, then lightly squeezing together the side prongs that hold the can in place, one prong at a time (this is by far the /WORSE/part of the operation, and the most time-consuming). The can is slipped off the assembly, rearward (where the 3 tubes were). Next, with a pair of long needle-nose pliers, each brass spacer that you see at the front of the vertical PTO board is
[Drakelist] T-4XC Unstable PTO (I think)
Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Unstable PTO (I think)
Hi Bob: Not sure you could see a slight frequency shift of a few hertz with a scope. Unless it was accompanied by an amplitude abberation. Does the PTO in question have the ground jumper braid to the shaft slider? See the WB4 HFN site for info on this if not. Curt On 10/26/2011 9:32 AM, Robert Fish wrote: Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Unstable PTO (I think)
Hi Bob, Don't even START me on this topic!!!: ) ~73~ de Eddy VE3CUI - VE3XZ * On 2011-10-26, at 10:32 AM, Robert Fish wrote: Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Unstable PTO (I think)
I know Eddy, I was going to mention your recent adventures in my opening post. Does it sound like the same issue your PTO had? yours was in a R-4 or R-4A as I recall, not that it matters. There was something about a dogbone cap in the PTO. Maybe I should go back and read that thread, eh? Bob K6GGO */Hi Bob,/* Don't even /START/me on this topic!!! * : )* */~73~ de Eddy VE3CUI - VE3XZ/* * On 2011-10-26, at 10:32 AM, Robert Fish wrote: Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net mailto:Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Unstable PTO (I think)
Hi Bob, My PTO is from a T-4X transmitter... My most recent fix to it was the complete replacement of all of the frequency determining capacitors in it (the bad solder joints were all dispatched earlier, one by one). I recently took to monitoring the actual PTO signal on a separate general coverage receiver, as well as the final spot signal on another: in BOTH cases the frequency will jump, indicating that the fault lies within the PTO itself. The latest incantation happens like this: both signals sound great for a long time---but then suddenly they will rise EVER so slowly. And then, pop! It'll go right back to the original frequency. This will go on for upwards of a half hour, or so, and then very suddenly, bang---both frequencies will go (or down) almost 2-KHz. My attention to the thing has been temporarily diverted by other things, but I have the PTO out of its mounting, have ID'ed all of the resistors that are part of the PTO oscillator transistor itself. I am hoping to replace ALL of these resistors with factory fresh new ones, going on the assumption that these rascals are (ONE of them, anyway) is changing under load ever so slightly, enough to affect some critical voltage in the stage, screwing-up the stability... Gosh, I've tried just about everything else...! ~73~ de Eddy VE3CUI - VE3XZ * On 2011-10-26, at 11:48 AM, Robert Fish wrote: I know Eddy, I was going to mention your recent adventures in my opening post. Does it sound like the same issue your PTO had? yours was in a R-4 or R-4A as I recall, not that it matters. There was something about a dogbone cap in the PTO. Maybe I should go back and read that thread, eh? Bob K6GGO Hi Bob, Don't even START me on this topic!!!: ) ~73~ de Eddy VE3CUI - VE3XZ * On 2011-10-26, at 10:32 AM, Robert Fish wrote: Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Unstable PTO (I think)
Bob - You would not be able to see a few tens of Hertz change on a scope. The warbling of the calibrator signal is often a power supply thing, C179 on the Calibrator board. Since it's intermittent, it's more likely a bad ground, I'd suggest 'exercising' the Calibrator plug by moving the board up and down a bit. DeoxIT on the connector pins wouldn't hurt. There are two primary causes for PTO instability. One has been going on for years, which is the intermittent grounding of the PTO slug and drive screw. The grounding path(s) are through the drive follower riding on the chrome rider bar at the top of the gearbox, and the ball bearings in the front plate. Hardened grease forms little 'chunks' that break the path through the ball bearings, causing frequency jitter when tuned. Usually not a problem when tuning is stopped. Drake offered a 'fix' of a small piece of wire braid soldered from the drive follower to the side wall of the gearbox. The field change is on the CD in the MISC directory. The second cause seems to be happening more often lately, and is the breakdown of one or more of the capacitors in the frequency determining circuit of the PTO. There are a couple of 'common' culprits, depending upon which of the 17 versions of PTO that you have. You should be able to see the jitter on a counter, the changes are tens of Hz if you can hear them. Freeze spray can help to isolate the defective cap(s), but not always. In the C-Line PTO C157 and/or C203, which may be either two 45 pF NP0 tubular ceramic caps or a single 90 pF is the most common troublemaker. It's best to measure the value of the existing cap and then choose a replacement as close as possible. C158 and C159 are selected at test to compensate for variations of C157 for linearity, and if you select C157 accurately linearity doesn't seem to be impacted. Less likely causes are a bad FET transistor Q8, or a bad Zener diode CR6. I have seen one case of a leaky C151. The trials and tribulations of PTO repair are in the archives about a month ago on this list and on DrakeRadio. -- 73, Garey - K4OAH St Charles, IL Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Robert Fish wrote: Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Unstable PTO (I think)
You would not be able to see a few tens of Hertz change on a scope. One method of observing small changes in frequency (and phase) is to utilize the X-Y function on a scope to display a Lissajous pattern. I have no doubt Garey has done this in the past. For others, one simply takes a known-stable RF generator and feed it into Channel 1 of the scope. The PTO output is fed into Channel 2. The scope time base is set to X-Y mode. Next, the stable generator amplitude can be set to approximately equal that of the PTO. Amplitude equality does not have to be very precise. As frequency changes, so will phase. Two in phase and on-frequency signals will show on the scope's displays as a straight 45 degree line. As the PTO changes frequency, the line will turn into an oblong loop and continuing further, a perfect circle at 90 degrees of phase difference, then it will show as a straight line again but at the 135 and 315 degree points on the scope's display. With the Lissajous method, even the slightest change in frequency between two sources can be displayed on a scope. Paul, W9AC - Original Message - From: Garey Barrell k4...@mindspring.com To: Robert Fish rwf...@comcast.net Cc: drakelist@zerobeat.net Sent: Wednesday, October 26, 2011 12:21 PM Subject: Re: [Drakelist] T-4XC Unstable PTO (I think) Bob - You would not be able to see a few tens of Hertz change on a scope. The warbling of the calibrator signal is often a power supply thing, C179 on the Calibrator board. Since it's intermittent, it's more likely a bad ground, I'd suggest 'exercising' the Calibrator plug by moving the board up and down a bit. DeoxIT on the connector pins wouldn't hurt. There are two primary causes for PTO instability. One has been going on for years, which is the intermittent grounding of the PTO slug and drive screw. The grounding path(s) are through the drive follower riding on the chrome rider bar at the top of the gearbox, and the ball bearings in the front plate. Hardened grease forms little 'chunks' that break the path through the ball bearings, causing frequency jitter when tuned. Usually not a problem when tuning is stopped. Drake offered a 'fix' of a small piece of wire braid soldered from the drive follower to the side wall of the gearbox. The field change is on the CD in the MISC directory. The second cause seems to be happening more often lately, and is the breakdown of one or more of the capacitors in the frequency determining circuit of the PTO. There are a couple of 'common' culprits, depending upon which of the 17 versions of PTO that you have. You should be able to see the jitter on a counter, the changes are tens of Hz if you can hear them. Freeze spray can help to isolate the defective cap(s), but not always. In the C-Line PTO C157 and/or C203, which may be either two 45 pF NP0 tubular ceramic caps or a single 90 pF is the most common troublemaker. It's best to measure the value of the existing cap and then choose a replacement as close as possible. C158 and C159 are selected at test to compensate for variations of C157 for linearity, and if you select C157 accurately linearity doesn't seem to be impacted. Less likely causes are a bad FET transistor Q8, or a bad Zener diode CR6. I have seen one case of a leaky C151. The trials and tribulations of PTO repair are in the archives about a month ago on this list and on DrakeRadio. -- 73, Garey - K4OAH St Charles, IL Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Robert Fish wrote: Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability
[Drakelist] T-4XC PTO chirps
Bob - Don't be surprised that you don't see anything on the scope trace when viewing a chirpy PTO signal. 10 Hz or even a few tens of Hz will likely not be visible on an oscilloscope as it represents a fraction of a percent of the frequency involved. The usual things to check first are: is the yoke grounded? (I believe there is a strap on the C-Line, IIRC); Is your regulated voltage to the PTO holding solid? IMO, if both of the above are okay, you may be looking at what Garey and I found wrong with my R-4A a while back - a bad silver-mica capacitor in the resonant circuit. The one that went bad in mine wasn't a typical-looking part, but a tubular one with color-coding. In the bipolar PTO, its value was about 92 pF - check your schematic. It will be the one that's in direct parallel with the coil. Removing the PTO - at least with the A's and B's - requires removal of the front panel. This is a good time to clean it as well as the fiducial window. Use only dish soap for the window or you'll take off the red line! Let us know how you make out. 73, Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! Message: 6 Date: Wed, 26 Oct 2011 07:32:16 -0700 From: Robert Fish rwf...@comcast.net To: drakelist@zerobeat.net drakelist@zerobeat.net Subject: [Drakelist] T-4XC Unstable PTO (I think) Message-ID: 4ea819f0.4020...@comcast.net Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hi Guys, I have been ignoring an issue with my T-4XC until recently. When I use the R-4C PTO to control the receiver it seems to work fine. When I use the T-4XC PTO to control the receiver I get sort of a chirpy, jumping around of the cw signal I am trying to copy. Both units work fine in transceive using the R-4C PTO, which is the way I have been using them. But with the recent DX expeditions (T32C, TX7M) running split, I have been having to use the C-line as separates to work them. I have had some success working them, but heaven knows what my signal sounds like. I have been putting off fixing this problem as I felt it was probably the PTO and I haven't been in the mood for performing major surgery lately. I decided to get off my arse and do something about it yesterday. So, I got out the scope and took a look at the T-4XC PTO output while it was controlling the R-4C. It seems stable. So I looked at the Plate of V-8 with the scope, I have a composite signal (PTO, Xtal Osc.) it looks solid as a rock. So then I looked at the injection signal right at the jack on the back of the T-4XC and once again, I can hear a cw signal I tuned in on the R-4C jumping all over the place, while I'm looking at a rock solid injection sig leaving the T-4XC. I switch back to the R-4C PTO and the jumping around stops, the receiver copies the same cw sig with stability. What am I missing here? It is hard to fix something when it seems like the only evidence of a problem is coming out of the speaker. If I could find some evidence of the problem I could follow it to it's source. This could be operator error (probably is) I only put about an hour in to this last night as I got called to dinner and a man has to have priorities. I am going to dig in to it this morning, I will eventually find the problem, but maybe you guys can save me some time. Ohanother clue: When I use the spot function, in CW mode, I get a warbling sound in the R-4C instead of a solid cw tone when tuning in the T-4XC sig with the receiver. It seems sort of intermittant (it switches to a cw tone sometimes and then goes back to warbling like you get in SSB mode with the spot function.) Thanks in advance, I hope this long winded post made sense. Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
On 2011-10-26, at 1:16 PM, Steve Wedge wrote: Removing the PTO - at least with the A's and B's - requires removal of the front panel. This is a good time to clean it as well as the fiducial window. Use only dish soap for the window or you'll take off the red line! Hi Guys, Well, I can not vouch for the A B series, but in my T-4X transmitter that extensive a dis-aasembly is most assuredly NOT required... After removing the three tubes immediately behind the PTO can, the can itself is extricated by first dis-connecting the top grounding spring, then lightly squeezing together the side prongs that hold the can in place, one prong at a time (this is by far the WORSE part of the operation, and the most time-consuming). The can is slipped off the assembly, rearward (where the 3 tubes were). Next, with a pair of long needle-nose pliers, each brass spacer that you see at the front of the vertical PTO board is grasped (so the spacers won't fall get lost), and a slotted screw driver is used to unscrew the 4 screws that go through them. The PTO board coil assembly is now loose, save for the 3 wires that are attached to the front vertical board: draw a simple sketch showing where these are connected so that you'll remember when you re-assemble everything, then touch each point on the board with a soldering iron to release each wire... The entire assembly is then slipped back off of the brass rod with the ferrite slugs on it. Absolutely no need to remove the front panel, no need for anything that complicated, or involved... To re-assemble, simply reverse this procedure! Hi Hi ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
Garey, Eddy, Paul, Curt and Steve, Thanks for the quick replies guys. This is a great bunch on this list. I am convinced that it is the PTO. If I lightly tap on the PTO can with a pencil tip (and I mean very lightly) it causes the signal to jump around. Maybe just a cold solder joint. I have a parts radio (T-4XC) with a PTO in it. I guess I'll haul it out and test it. If it's stable, I will swap it with the faulty one. Can I then rebuild (shotgun) the bad PTO with all new parts? or is there special parts in there that I have to be careful with? I probably have most of the stuff in stock (NPO caps, metal film resistors etc.). It would be handy to have a nice new spare because I also have a B-Line. Also, A 5Mhz PTO is a nice thing to have around, homebrew QRP rigs etc. I have a HP signal generator, so I think I will try Paul's suggestion on the Lissajous display. Perhaps I can find the faulty component with some freeze spray and make this a quick repair. Maybe learn something in the process (heaven forbid). I wrote this e-mail in three sittings as real life keeps intervening. The bottom line is, thanks for all the help, I will let you know how I proceed and the results thereof. 73, Bob K6GGO On 2011-10-26, at 1:16 PM, Steve Wedge wrote: Removing the PTO - at least with the A's and B's - requires removal of the front panel. This is a good time to clean it as well as the fiducial window. Use only dish soap for the window or you'll take off the red line! */ /* */Hi Guys,/* Well, I can not vouch for the A B series, but in my T-4X transmitter /that/extensive a dis-aasembly is most assuredly */NOT/*required... After removing the three tubes immediately behind the PTO can, the can itself is extricated by first dis-connecting the top grounding spring, then lightly squeezing together the side prongs that hold the can in place, one prong at a time (this is by far the /WORSE/part of the operation, and the most time-consuming). The can is slipped off the assembly, rearward (where the 3 tubes were). Next, with a pair of long needle-nose pliers, each brass spacer that you see at the front of the vertical PTO board is grasped (so the spacers won't fall get lost), and a slotted screw driver is used to unscrew the 4 screws that go through them. The PTO board coil assembly is now loose, save for the 3 wires that are attached to the front vertical board: draw a simple sketch showing where these are connected so that you'll remember when you re-assemble everything, then touch each point on the board with a soldering iron to release each wire... The entire assembly is then slipped back off of the brass rod with the ferrite slugs on it. Absolutely /no need/to remove the front panel, no need for /anything/that complicated, or involved... To re-assemble, simply reverse this procedure! Hi Hi */~73~ de Eddy VE3CUI - VE3XZ/* ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
We all enjoy these rigs, Bob. If it was me, I'd try one part at a time and hook it up to a regulated supply and a counter. You can then log the frequency every time you walk by and see, over time, if changing the part fixed the problem. I'd start with just the PTO before replacing anything. Log what the counter is telling you any time you happen to look over at it. Don't destroy any parts in case you find you've made matters worse so you can return to the zero point. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Robert Fish To: Drakelist@zerobeat.net Sent: Wednesday, October 26, 2011 3:28 PM Subject: Re: [Drakelist] T-4XC PTO chirps Garey, Eddy, Paul, Curt and Steve, Thanks for the quick replies guys. This is a great bunch on this list. I am convinced that it is the PTO. If I lightly tap on the PTO can with a pencil tip (and I mean very lightly) it causes the signal to jump around. Maybe just a cold solder joint. I have a parts radio (T-4XC) with a PTO in it. I guess I'll haul it out and test it. If it's stable, I will swap it with the faulty one. Can I then rebuild (shotgun) the bad PTO with all new parts? or is there special parts in there that I have to be careful with? I probably have most of the stuff in stock (NPO caps, metal film resistors etc.). It would be handy to have a nice new spare because I also have a B-Line. Also, A 5Mhz PTO is a nice thing to have around, homebrew QRP rigs etc. I have a HP signal generator, so I think I will try Paul's suggestion on the Lissajous display. Perhaps I can find the faulty component with some freeze spray and make this a quick repair. Maybe learn something in the process (heaven forbid). I wrote this e-mail in three sittings as real life keeps intervening. The bottom line is, thanks for all the help, I will let you know how I proceed and the results thereof. 73, Bob K6GGO On 2011-10-26, at 1:16 PM, Steve Wedge wrote: Removing the PTO - at least with the A's and B's - requires removal of the front panel. This is a good time to clean it as well as the fiducial window. Use only dish soap for the window or you'll take off the red line! Hi Guys, Well, I can not vouch for the A B series, but in my T-4X transmitter that extensive a dis-aasembly is most assuredly NOT required... After removing the three tubes immediately behind the PTO can, the can itself is extricated by first dis-connecting the top grounding spring, then lightly squeezing together the side prongs that hold the can in place, one prong at a time (this is by far the WORSE part of the operation, and the most time-consuming). The can is slipped off the assembly, rearward (where the 3 tubes were). Next, with a pair of long needle-nose pliers, each brass spacer that you see at the front of the vertical PTO board is grasped (so the spacers won't fall get lost), and a slotted screw driver is used to unscrew the 4 screws that go through them. The PTO board coil assembly is now loose, save for the 3 wires that are attached to the front vertical board: draw a simple sketch showing where these are connected so that you'll remember when you re-assemble everything, then touch each point on the board with a soldering iron to release each wire... The entire assembly is then slipped back off of the brass rod with the ferrite slugs on it. Absolutely no need to remove the front panel, no need for anything that complicated, or involved... To re-assemble, simply reverse this procedure! Hi Hi ~73~ de Eddy VE3CUI - VE3XZ -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC PTO chirps
You're right, Eddy. I do prefer to remove the entire subassembly as it makes it much easier to work on. I can RR the front panel in about 10 minutes, I'm so used to it... Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar To: Steve Wedge ; Bob Fish Fish Cc: drakelist@zerobeat.net Sent: Wednesday, October 26, 2011 2:10 PM Subject: Re: [Drakelist] T-4XC PTO chirps On 2011-10-26, at 1:16 PM, Steve Wedge wrote: Removing the PTO - at least with the A's and B's - requires removal of the front panel. This is a good time to clean it as well as the fiducial window. Use only dish soap for the window or you'll take off the red line! Hi Guys, Well, I can not vouch for the A B series, but in my T-4X transmitter that extensive a dis-aasembly is most assuredly NOT required... After removing the three tubes immediately behind the PTO can, the can itself is extricated by first dis-connecting the top grounding spring, then lightly squeezing together the side prongs that hold the can in place, one prong at a time (this is by far the WORSE part of the operation, and the most time-consuming). The can is slipped off the assembly, rearward (where the 3 tubes were). Next, with a pair of long needle-nose pliers, each brass spacer that you see at the front of the vertical PTO board is grasped (so the spacers won't fall get lost), and a slotted screw driver is used to unscrew the 4 screws that go through them. The PTO board coil assembly is now loose, save for the 3 wires that are attached to the front vertical board: draw a simple sketch showing where these are connected so that you'll remember when you re-assemble everything, then touch each point on the board with a soldering iron to release each wire... The entire assembly is then slipped back off of the brass rod with the ferrite slugs on it. Absolutely no need to remove the front panel, no need for anything that complicated, or involved... To re-assemble, simply reverse this procedure! Hi Hi ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC schematic
Can someone tell me where I can get a nice clean full size schematic for a Drake T-4XC that I can actually read? I am willing to pay to have it copied and mailed. Hank___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC schematic
Hank - If you had my CD for the C-Line, you'd have a clean schematic of BOTH T-4XC Schematics, along with a lot of other stuff.. If you send me your s/n, I'll send you the correct schematic via attachment. It will print out a 2' x 4' if you wish at a Kinko's or other large format printer, or any other size down to 8-1/2 x 11 (a little hard to read!) -- 73, Garey - K4OAH St Charles, IL Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Henry Foglesong wrote: Can someone tell me where I can get a nice clean full size schematic for a Drake T-4XC that I can actually read? I am willing to pay to have it copied and mailed. Hank ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Output Varies
I had the same issue with mine. Pout would start at 140 watts at initial key down, and drift down to 90 watts. Rebuilt the AC-4 as the plate caps were leaking (could only see leak after removing tall lytics). Did my own rebuild with two 270 uf, 450 volt caps that I had laying around. Pout is now constant. BTW, the rebuild also fixed a sidetone issue. Look at B+ on AC-4 and see if it drifts down when you key, or just rebuild the psu for peace of mind. Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Varies
I hope you also replaced at least the BIAS supply caps as well.. And preferably the LV supply caps too! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Jim Bo wrote: I had the same issue with mine. Pout would start at 140 watts at initial key down, and drift down to 90 watts. Rebuilt the AC-4 as the plate caps were leaking (could only see leak after removing tall lytics). Did my own rebuild with two 270 uf, 450 volt caps that I had laying around. Pout is now constant. BTW, the rebuild also fixed a sidetone issue. Look at B+ on AC-4 and see if it drifts down when you key, or just rebuild the psu for peace of mind. Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Power Varies...................
Jim, If you are still having output problems w/variation between sep/rcv/xmit, PLEASE try replacing the T4XC's 6EJ7 tube...you might be surprised with the results! I had a problem vy similar to yours. PLEASE let me know if it does the trick! Regards, Ed K3JJG Unionville, PA___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Plate Current
Is it normal for the T-4XC plate current to read 120 mA when: 1. in CW mode 2. Xmitter is keyed using mic line (no mic element connected, just foot switch). I have adjusted the bias per the manual at the mark on the meter. If not normal, any ideas as to what the issue may be? Thanks Jim___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC on 160 Meters
When tuning the T-4XC on 160 meters, into a dummy load, the load control is at zero or maximum capacitance. I clearly do not get a peak in output power when changing the load control, the Pout continue to increase until I hit zero on the dial (max. cap). The plate control clearly has a peak at 3 on the dial. Comments?? Thanks Jim___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Plate Current
Do you have a key plugged, and 'open'? Will the current 'dip' with the PLATE control? Is GAIN control at CCW? 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Jim Bo wrote: Is it normal for the T-4XC plate current to read 120 mA when: 1. in CW mode 2. Xmitter is keyed using mic line (no mic element connected, just foot switch). I have adjusted the bias per the manual at the mark on the meter. If not normal, any ideas as to what the issue may be? Thanks Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC load question
Gang, Well I had a ball this week end with the DX contestI used te Drake C lne most of the time! Just like the old days. I did se the TT OII and Collins some too. On (T-4XC) 80 40, when I tune up. When I advance the load control it is fine... peaks out then just (very slightly) after peak the power output goes to a few watts? I do know you are supposed to stop just before the peak. Seems to be 80/40 and not 20/15/10. Any ideas what's going on? 73, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC load question
Ah HAH! Yes, I think that was it...The load var cap was not shorting but, on the front section of the 3, in the mid range...it was very close. Maybe close enough to arc?? Anyways, I adjusted 3 different platesit to provide more clearance, and so far it is working OK Thanks Garey! I would not have thought of that, it must have been that way a long time. 73, Lee Lee Simmonds Summit DCS LLC 260-799-4077 Office 260-403-6936 Cell -Original Message- From: Garey Barrell k4...@mindspring.com To: drakelist Drakelist@zerobeat.net Sent: Sun, Mar 6, 2011 7:08 pm Subject: Re: [Drakelist] T-4XC load question Lee - Strange. Do you have to advance the LOAD control further CW on 80/40 than you do on 20/15/10? Sounds almost like a bent plate on the LOAD capacitor!??! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com kc9...@aol.com wrote: Gang, Well I had a ball this week end with the DX contestI used te Drake C lne most of the time! Just like the old days. I did se the TT OII and Collins some too. On (T-4XC) 80 40, when I tune up. When I advance the load control it is fine... peaks out then just (very slightly) after peak the power output goes to a few watts? I do know you are supposed to stop just before the peak. Seems to be 80/40 and not 20/15/10. Any ideas what's going on? 73, Lee ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Power Varies...................
Jim - It is normal for there to be a 'small' difference between power output and receiver sensitivity in the various TRANSCEIVE switch positions. First, the INJ cable MUST be a low capacitance coax or mic cable. Cable impedance, loss, shielding, etc. are NOT important, only the 'capacitance per foot'. The original cables were all 38 long, tip to tip. Original Drake INJ and CAR OSC Cables = 19 pF/ft = .160 o.d. (foam poly) RG-62 = 93R = 13.5 pF/ft = 0.240 o.d. RG-59 = 75R = 14.8 pF/ft = 0.242 o.d. RG-6 = 75R = 16.2 pF/ft = 0.270 o.d. RG-174= 50R = 30.8 pF/ft = 0.110 o.d. Mic Cable (Belden 8410) = Hi-Z = 33 pf/ft = 0.160 o.d. (foam poly) Mic Cable (Belden 8421) = Hi-Z = 16 pf/ft = 0.180 o.d. (foam poly) R/S Audio Patch Cable = 28 pF/ft = 0.165 o.d. (poly) The best choice is the Belden 8421 Audio cable from their Brilliance line. It looks just like the other cables, and is very flexible. The RG-62 is OK, but it is 50% larger and far less flexible. RG-62 is also prone to shorting if bent over too small a radius, and is susceptible to heat damage when soldering connectors. The best feature of RG-62 is that it is often FREE, since there have been many miles of it pulled out of old computer networks. Belden 8421 has been available by the foot from someone on the list in the recent past. The CAR OSC cable in the C-Line should be the same cable, although it isn't quite as critical. The proper cables will minimize the difference, however it may still require a touch-up of the RF TUNE and GAIN controls as well as the PRESELECTOR control in the receiver. Especially in CW, the GAIN control must be advanced further. The ALC masks this in TUNE, but the GAIN control is more critical in CW. It also helps to do the PreMixer alignment steps with the two cabled together using the correct cables. It does sound like your GAIN control is on the low side. Typically, on 40M in TUNE, you should get full output (typically 130W, limited by ALC) before 12 o'clock. CW shouldn't require more than about 1 o'clock for full output. These are two different controls on the same shaft. In TUNE one section is an AF gain control adjusting the level of a 1 kHz audio tone into the Balanced Modulator, similar to whistling into the microphone. In CW, the other section controls a DC current applied to the diodes in the Balanced Modulator to un-balance it and allow the Carrier Oscillator to come through to be amplified and mixed to generate the CW signal. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Jim Bo wrote: My T-4XC has different Pout depending on the position of the transceive switch and in the CW Mode. With transceive swith set on separate Gain is at 2:30 Plate current is 300 ma Pout is 100 watts With transceive switch set on rcvr Gain is at 2:30 Plate current is 320 ma Pout is 117 watt When transceive switch is on xmtr Gain is at 2:30 Plate current is 140 ma Pout is 19 watts When transceive switch is on xmtr Gain is at 5:00 (fully clockwise) Palte current is 320 ma Pout is 117 watts What is pecular is that Pout when seperate compared to Pout when xmtr supposedly uses the same oscillator signal for drive. I did not see anything in the manual that looks like there is an alignment step for this. Comments? Thanks Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Power Varies...................
Garey, The cables I use for these 2 connections have a small metal clip on each end.. I think these are the ones Drake sold for that purpose?? 73, Lee -Original Message- From: Garey Barrell k4...@mindspring.com To: drakelist drakelist@zerobeat.net Sent: Tue, Mar 1, 2011 10:32 am Subject: Re: [Drakelist] T-4XC Output Power Varies... Jim - It is normal for there to be a 'small' difference between power output and receiver sensitivity in the various TRANSCEIVE switch positions. First, the INJ cable MUST be a low capacitance coax or mic cable. Cable impedance, loss, shielding, etc. are NOT important, only the 'capacitance per foot'. The original cables were all 38 long, tip to tip. Original Drake INJ and CAR OSC Cables = 19 pF/ft = .160 o.d. (foam poly) RG-62 = 93R = 13.5 pF/ft = 0.240 o.d. RG-59 = 75R = 14.8 pF/ft = 0.242 o.d. RG-6 = 75R = 16.2 pF/ft = 0.270 o.d. RG-174= 50R = 30.8 pF/ft = 0.110 o.d. Mic Cable (Belden 8410) = Hi-Z = 33 pf/ft = 0.160 o.d. (foam poly) Mic Cable (Belden 8421) = Hi-Z = 16 pf/ft = 0.180 o.d. (foam poly) R/S Audio Patch Cable = 28 pF/ft = 0.165 o.d. (poly) The best choice is the Belden 8421 Audio cable from their Brilliance line. It looks just like the other cables, and is very flexible. The RG-62 is OK, but it is 50% larger and far less flexible. RG-62 is also prone to shorting if bent over too small a radius, and is susceptible to heat damage when soldering connectors. The best feature of RG-62 is that it is often FREE, since there have been many miles of it pulled out of old computer networks. Belden 8421 has been available by the foot from someone on the list in the recent past. The CAR OSC cable in the C-Line should be the same cable, although it isn't quite as critical. The proper cables will minimize the difference, however it may still require a touch-up of the RF TUNE and GAIN controls as well as the PRESELECTOR control in the receiver. Especially in CW, the GAIN control must be advanced further. The ALC masks this in TUNE, but the GAIN control is more critical in CW. It also helps to do the PreMixer alignment steps with the two cabled together using the correct cables. It does sound like your GAIN control is on the low side. Typically, on 40M in TUNE, you should get full output (typically 130W, limited by ALC) before 12 o'clock. CW shouldn't require more than about 1 o'clock for full output. These are two different controls on the same shaft. In TUNE one section is an AF gain control adjusting the level of a 1 kHz audio tone into the Balanced Modulator, similar to whistling into the microphone. In CW, the other section controls a DC current applied to the diodes in the Balanced Modulator to un-balance it and allow the Carrier Oscillator to come through to be amplified and mixed to generate the CW signal. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Jim Bo wrote: My T-4XC has different Pout depending on the position of the transceive switch and in the CW Mode. With transceive swith set on separate Gain is at 2:30 Plate current is 300 ma Pout is 100 watts With transceive switch set on rcvr Gain is at 2:30 Plate current is 320 ma Pout is 117 watt When transceive switch is on xmtr Gain is at 2:30 Plate current is 140 ma Pout is 19 watts When transceive switch is on xmtr Gain is at 5:00 (fully clockwise) Palte current is 320 ma Pout is 117 watts What is pecular is that Pout when seperate compared to Pout when xmtr supposedly uses the same oscillator signal for drive. I did not see anything in the manual that looks like there is an alignment step for this. Comments? Thanks Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Power Varies...................
Lee - Yes, some had a small tag, others just had a metal ring or clip. Regular cables usually had phenolic insulators in the connectors, while the low-C cables had clear or white insulators. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com kc9...@aol.com wrote: Garey, The cables I use for these 2 connections have a small metal clip on each end.. I think these are the ones Drake sold for that purpose?? 73, Lee -Original Message- From: Garey Barrell k4...@mindspring.com To: drakelist drakelist@zerobeat.net Sent: Tue, Mar 1, 2011 10:32 am Subject: Re: [Drakelist] T-4XC Output Power Varies... Jim - It is normal for there to be a 'small' difference between power output and receiver sensitivity in the various TRANSCEIVE switch positions. First, the INJ cable MUST be a low capacitance coax or mic cable. Cable impedance, loss, shielding, etc. are NOT important, only the 'capacitance per foot'. The original cables were all 38 long, tip to tip. Original Drake INJ and CAR OSC Cables = 19 pF/ft = .160 o.d. (foam poly) RG-62 = 93R = 13.5 pF/ft = 0.240 o.d. RG-59 = 75R = 14.8 pF/ft = 0.242 o.d. RG-6 = 75R = 16.2 pF/ft = 0.270 o.d. RG-174= 50R = 30.8 pF/ft = 0.110 o.d. Mic Cable (Belden 8410) = Hi-Z = 33 pf/ft = 0.160 o.d. (foam poly) Mic Cable (Belden 8421) = Hi-Z = 16 pf/ft = 0.180 o.d. (foam poly) R/S Audio Patch Cable = 28 pF/ft = 0.165 o.d. (poly) The best choice is the Belden 8421 Audio cable from their Brilliance line. It looks just like the other cables, and is very flexible. The RG-62 is OK, but it is 50% larger and far less flexible. RG-62 is also prone to shorting if bent over too small a radius, and is susceptible to heat damage when soldering connectors. The best feature of RG-62 is that it is often FREE, since there have been many miles of it pulled out of old computer networks. Belden 8421 has been available by the foot from someone on the list in the recent past. The CAR OSC cable in the C-Line should be the same cable, although it isn't quite as critical. The proper cables will minimize the difference, however it may still require a touch-up of the RF TUNE and GAIN controls as well as the PRESELECTOR control in the receiver. Especially in CW, the GAIN control must be advanced further. The ALC masks this in TUNE, but the GAIN control is more critical in CW. It also helps to do the PreMixer alignment steps with the two cabled together using the correct cables. It does sound like your GAIN control is on the low side. Typically, on 40M in TUNE, you should get full output (typically 130W, limited by ALC) before 12 o'clock. CW shouldn't require more than about 1 o'clock for full output. These are two different controls on the same shaft. In TUNE one section is an AF gain control adjusting the level of a 1 kHz audio tone into the Balanced Modulator, similar to whistling into the microphone. In CW, the other section controls a DC current applied to the diodes in the Balanced Modulator to un-balance it and allow the Carrier Oscillator to come through to be amplified and mixed to generate the CW signal. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Jim Bo wrote: My T-4XC has different Pout depending on the position of the transceive switch and in the CW Mode. With transceive swith set on separate Gain is at 2:30 Plate current is 300 ma Pout is 100 watts With transceive switch set on rcvr Gain is at 2:30 Plate current is 320 ma Pout is 117 watt When transceive switch is on xmtr Gain is at 2:30 Plate current is 140 ma Pout is 19 watts When transceive switch is on xmtr Gain is at 5:00 (fully clockwise) Palte current is 320 ma Pout is 117 watts What is pecular is that Pout when seperate compared to Pout when xmtr supposedly uses the same oscillator signal for drive. I did not see anything in the manual that looks like there is an alignment step for this. Comments? Thanks Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Power Varies...................
Garey, Thanks for the response. I am using Belden RG-59U for the injection cable. Spec is 16.3 pf/foot and I have one foot length, so the capacitance of the cable is less than what Drake specifies. I do not have the Carrier Osc cable connected between the rigs as I understand that is for SSB only and dows not play a role in CW, but will try connecting with a 1 foot piece of Belden RG-59U (again will result in less capacitance than what Drake spec'ed). I am not sure what you mean by a touch-up of the RF TUNE and GAIN controls as well as the PRESELECTOR control in the receiver. I re-peaked both preselectors on the rcvr and xmitter and still have a big difference betweenxmtr and separate switch positions. Am I correct in saying the source of the drive for the final amplifier is same for the xmtr and separate position of the transceive switch?? Big difference between 19 watts and 100 watts. Also, what causes the need to advance the gain control so far for CW, or should I even worry about that? Is there an adjustment for that? I do not see anything in the manual that says to adjust this. Tnx Jim Message: 5 Date: Tue, 01 Mar 2011 10:30:42 -0500 From: Garey Barrell k4...@mindspring.com To: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4XC Output Power Varies... Message-ID: 4d6d1122.4020...@mindspring.com Content-Type: text/plain; charset=windows-1252; format=flowed Jim - It is normal for there to be a 'small' difference between power output and receiver sensitivity in the various TRANSCEIVE switch positions. First, the INJ cable MUST be a low capacitance coax or mic cable. Cable impedance, loss, shielding, etc. are NOT important, only the 'capacitance per foot'. The original cables were all 38 long, tip to tip. Original Drake INJ and CAR OSC Cables = 19 pF/ft = .160 o.d. (foam poly) RG-62 = 93R = 13.5 pF/ft = 0.240 o.d. RG-59 = 75R = 14.8 pF/ft = 0.242 o.d. RG-6 = 75R = 16.2 pF/ft = 0.270 o.d. RG-174= 50R = 30.8 pF/ft = 0.110 o.d. Mic Cable (Belden 8410) = Hi-Z = 33 pf/ft = 0.160 o.d. (foam poly) Mic Cable (Belden 8421) = Hi-Z = 16 pf/ft = 0.180 o.d. (foam poly) R/S Audio Patch Cable = 28 pF/ft = 0.165 o.d. (poly) The best choice is the Belden 8421 Audio cable from their Brilliance line. It looks just like the other cables, and is very flexible. The RG-62 is OK, but it is 50% larger and far less flexible. RG-62 is also prone to shorting if bent over too small a radius, and is susceptible to heat damage when soldering connectors. The best feature of RG-62 is that it is often FREE, since there have been many miles of it pulled out of old computer networks. Belden 8421 has been available by the foot from someone on the list in the recent past. The CAR OSC cable in the C-Line should be the same cable, although it isn't quite as critical. The proper cables will minimize the difference, however it may still require a touch-up of the RF TUNE and GAIN controls as well as the PRESELECTOR control in the receiver. Especially in CW, the GAIN control must be advanced further. The ALC masks this in TUNE, but the GAIN control is more critical in CW. It also helps to do the PreMixer alignment steps with the two cabled together using the correct cables. It does sound like your GAIN control is on the low side. Typically, on 40M in TUNE, you should get full output (typically 130W, limited by ALC) before 12 o'clock. CW shouldn't require more than about 1 o'clock for full output. These are two different controls on the same shaft. In TUNE one section is an AF gain control adjusting the level of a 1 kHz audio tone into the Balanced Modulator, similar to whistling into the microphone. In CW, the other section controls a DC current applied to the diodes in the Balanced Modulator to un-balance it and allow the Carrier Oscillator to come through to be amplified and mixed to generate the CW signal. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Output Power Varies...................
My T-4XC has different Pout depending on the position of the transceive switch and in the CW Mode. With transceive swith set on separate Gain is at 2:30 Plate current is 300 ma Pout is 100 watts With transceive switch set on rcvr Gain is at 2:30 Plate current is 320 ma Pout is 117 watt When transceive switch is on xmtr Gain is at 2:30 Plate current is 140 ma Pout is 19 watts When transceive switch is on xmtr Gain is at 5:00 (fully clockwise) Palte current is 320 ma Pout is 117 watts What is pecular is that Pout when seperate compared to Pout when xmtr supposedly uses the same oscillator signal for drive. I did not see anything in the manual that looks like there is an alignment step for this. Comments? Thanks Jim___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Output Power Varies...
Two tips, First hit the switch with Deoxite. Second double check the cables you are using. I believe the INJ, CARRIER, and one other cable need to be a special low loss double shielded cable. Some of the resident experts will chime in I hope and correct any miss-information I might be spreading. Don Jones KO7i Arlington, WA Message: 8 Date: Mon, 28 Feb 2011 21:48:01 -0800 From: Jim Bo jbol...@verizon.net To: drakelist@zerobeat.net Subject: [Drakelist] T-4XC Output Power Varies... Message-ID: 689C305DD4144A1F8096AFDD0907740A@JDESK Content-Type: text/plain; charset=windows-1252 My T-4XC has different Pout depending on the position of the transceive switch and in the CW Mode. With transceive swith set on separate Gain is at 2:30 Plate current is 300 ma Pout is 100 watts With transceive switch set on rcvr Gain is at 2:30 Plate current is 320 ma Pout is 117 watt When transceive switch is on xmtr Gain is at 2:30 Plate current is 140 ma Pout is 19 watts When transceive switch is on xmtr Gain is at 5:00 (fully clockwise) Palte current is 320 ma Pout is 117 watts What is pecular is that Pout when seperate compared to Pout when xmtr supposedly uses the same oscillator signal for drive. I did not see anything in the manual that looks like there is an alignment step for this. Comments? Thanks Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Problem has come back............................
Well, a few hours into CQWW CWDX contest, the xmitter started to act up again. Seems to be temp related also. I lose the sidetone and the xmitter will not go into xmit when I hit the CW key. I also found that the spot function does not work. If I key the xmitter with an external foot switch, the spot function works, but the xmitter will not go into the transmit mode and the side tone does not. I was working the contest with the receiver in the ON position so I could get sidetone, as the keyer I have does not have a sidetone on it. Any other ideas on where to look? Garey, I need to re-read yours, but no longer have it, can you re-send? Thanks to all Jim (just recovering from a turkey coma) WA9ZBV ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Oscillation and tone problem solved.
I dont have a c version schematic but... In my fan rectifier adventures, I found that the drakes use a 12V CT filament winding..the CT is grounded ..the 12V tubes are across the whole winding...So you cannot ground one side of the rectifier/fan voltage. If you go from ground to one side of the winding, you only get 6.3V. I let the 12V fan and rectifier float..ie niether side is connected to ground. Works fine. What is different in the c version? Curt KU8L Jim Bo wrote: Guys, Thanks for eveyones help with the subject matter. The culprit for both of the problems was due to a circuit I added for a external fan supply. I went across the heater of V7 (Pin 3 and Pin 4) with a simple half wave rectifier circuit with 150 uF of cap for a filter. Pin 4 is at ground potential, so the diode was hanging off Pin 3. I ran this supply voltage to a 12 volt dc fan that was used to cool the final cage. For reasons unknown, the 'oscillation problem AND the poor receive tone when just the injection cable connected was due to this half wave rectifier circuit. After removal of the circuit, all is back to normal, sidetone is back and solid, no oscillation and no funny T6 (Tone 6) when the injection cable was connected. Now, tomorrow morning, I will kick around 15M and 20M on CQWW DX test CW with the new rig. Thanks for eveyones help! Jim WA9ZBV ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Oscillation and tone problem solved.
Curt, I want something around 6 volts or so DC so the fan will run slower and quite. Pin 3 and 4 is the filament for a 6AU6A tube, with pin 4 grounded at the tube socket. As soon as I disconneted the circuit, the oscillation went away, the raspy tone on received signals on the R-4C with the injection cable connnected went away and the sidetone came up in voulme. The fan draws less than 300 mils of current. Jim - Original Message - From: Curt Nixon cptc...@flash.net To: Jim Bo jbol...@verizon.net Cc: drakelist@zerobeat.net Sent: Saturday, November 27, 2010 7:20 AM Subject: Re: [Drakelist] T-4XC Oscillation and tone problem solved. I dont have a c version schematic but... In my fan rectifier adventures, I found that the drakes use a 12V CT filament winding..the CT is grounded ..the 12V tubes are across the whole winding...So you cannot ground one side of the rectifier/fan voltage. If you go from ground to one side of the winding, you only get 6.3V. I let the 12V fan and rectifier float..ie niether side is connected to ground. Works fine. What is different in the c version? Curt KU8L Jim Bo wrote: Guys, Thanks for eveyones help with the subject matter. The culprit for both of the problems was due to a circuit I added for a external fan supply. I went across the heater of V7 (Pin 3 and Pin 4) with a simple half wave rectifier circuit with 150 uF of cap for a filter. Pin 4 is at ground potential, so the diode was hanging off Pin 3. I ran this supply voltage to a 12 volt dc fan that was used to cool the final cage. For reasons unknown, the 'oscillation problem AND the poor receive tone when just the injection cable connected was due to this half wave rectifier circuit. After removal of the circuit, all is back to normal, sidetone is back and solid, no oscillation and no funny T6 (Tone 6) when the injection cable was connected. Now, tomorrow morning, I will kick around 15M and 20M on CQWW DX test CW with the new rig. Thanks for eveyones help! Jim WA9ZBV ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Oscillation and tone problem solved.
OK, I get it. You might want to try the Silenx fans..they are nearly silent. REALLY..can't hear them run. I was very impressed. New computer optimized blade designs. They are available on the online auction-site and from PC retailers. No need to slow them down. They also have a temp sensor controlled version that is only a couple of bucks more..but I still opted for the fixed speed ones even after testing the controlled versions..can't hear either one. T4 and R4 stay cool enough so that the PA cage is the cooles part of the top case and the rx pwr transformer and audio area is room temp on the top of the case. Pix: http://picasaweb.google.com/captcurt08/DrakeFanInstall# Also use them on the AC4 Glad you got it figured out but hard to guess what was going on.. normal rectifiers should make no noise that a rx can pick up. I pick up the 12V on the terminal strip where the fuse is mounted on the A and B versions. Curt Jim Bo wrote: Curt, I want something around 6 volts or so DC so the fan will run slower and quite. Pin 3 and 4 is the filament for a 6AU6A tube, with pin 4 grounded at the tube socket. As soon as I disconneted the circuit, the oscillation went away, the raspy tone on received signals on the R-4C with the injection cable connnected went away and the sidetone came up in voulme. The fan draws less than 300 mils of current. Jim - Original Message - From: Curt Nixon cptc...@flash.net To: Jim Bo jbol...@verizon.net Cc: drakelist@zerobeat.net Sent: Saturday, November 27, 2010 7:20 AM Subject: Re: [Drakelist] T-4XC Oscillation and tone problem solved. I dont have a c version schematic but... In my fan rectifier adventures, I found that the drakes use a 12V CT filament winding..the CT is grounded ..the 12V tubes are across the whole winding...So you cannot ground one side of the rectifier/fan voltage. If you go from ground to one side of the winding, you only get 6.3V. I let the 12V fan and rectifier float..ie niether side is connected to ground. Works fine. What is different in the c version? Curt KU8L Jim Bo wrote: Guys, Thanks for eveyones help with the subject matter. The culprit for both of the problems was due to a circuit I added for a external fan supply. I went across the heater of V7 (Pin 3 and Pin 4) with a simple half wave rectifier circuit with 150 uF of cap for a filter. Pin 4 is at ground potential, so the diode was hanging off Pin 3. I ran this supply voltage to a 12 volt dc fan that was used to cool the final cage. For reasons unknown, the 'oscillation problem AND the poor receive tone when just the injection cable connected was due to this half wave rectifier circuit. After removal of the circuit, all is back to normal, sidetone is back and solid, no oscillation and no funny T6 (Tone 6) when the injection cable was connected. Now, tomorrow morning, I will kick around 15M and 20M on CQWW DX test CW with the new rig. Thanks for eveyones help! Jim WA9ZBV ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Oscillation and tone problem solved.
Guys, Thanks for eveyones help with the subject matter. The culprit for both of the problems was due to a circuit I added for a external fan supply. I went across the heater of V7 (Pin 3 and Pin 4) with a simple half wave rectifier circuit with 150 uF of cap for a filter. Pin 4 is at ground potential, so the diode was hanging off Pin 3. I ran this supply voltage to a 12 volt dc fan that was used to cool the final cage. For reasons unknown, the 'oscillation problem AND the poor receive tone when just the injection cable connected was due to this half wave rectifier circuit. After removal of the circuit, all is back to normal, sidetone is back and solid, no oscillation and no funny T6 (Tone 6) when the injection cable was connected. Now, tomorrow morning, I will kick around 15M and 20M on CQWW DX test CW with the new rig. Thanks for eveyones help! Jim WA9ZBV ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Oscillation and tone problem solved.
On Fri, 26 Nov 2010 21:54:06 -0800, Jim Bo wrote: For reasons unknown, the 'oscillation problem AND the poor receive tone when just the injection cable connected was due to this half wave rectifier circuit. DC fans can put a considerable amount of electrical noise on the line. I've seen them tear up video in outdoor security cameras so equiped. Higher quality fans are less prone to this, but it's probably still a good idea to use some L/C filtering and RF bypassing on the DC line. The 150 uF by itself was probably not adeqate for high frequency noise. DC brushless fans have internal DC-to-AC converters (oscillators) that can generate nice square waves. Good catch, I'll have to check my T-4XC fan supply for noise. Someday sigh 73 -Jim (so much to do, so little time) -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Plot Thickens
Hooked up the rcvr to the xmitter with all the patch cords and something really weird is going on. When connected together the cw signals in the R-4C become REAL raspy, about a T6 on the RST scale! Very poor. Now if I remove only the inj cable, the tone goes back to normal. I have also noted that the receiver takes MUCH longer to come back on line after you release the xmit button. It is not the relay, but rather it sounds like something is discharging with a RC time constant as the receiver gets its ears back. Comments? Tnx Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC problem
Fixed the power fade (went from 120 watts to 80 watts within 5 seconds) by rebuilding the AC-4. All is well with the power supply, voltages are correct and ripple is good. What started the project was the fact the the xmitter, when in CW, with key down, I would get output power for two seconds. Then the transmitter would quit xmitting (heard relay click) for 1 second, then xmit for 2 seconds, then stop xmitting for 1 second. Just sat there and oscillated from output power to no output power (relay clicking every time). The frequency of this can be changed by cranking on the anti vox pot. I cleaned relay contacts, and rotary switch contacts to no avail. I searched the web and saw someone else with a similar problem, but the thread never did reach a conclusion that the problem was fixed. Comments from the gang?? Tnx Jim WA9ZBV ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Low Power Output on 160M
I have noticed that when loading up my T-4XC up on 160M I am only able to get 45 - 50W out of my transmitter. Seems as though the loading cap has insufficient range for proper tuning. The load control is fully CCW. Is there a problem with the transmitter or does it just need alignment? Thanks 73, Don Jones KO7i Arlington, WA ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Low Power Output on 160M
- Original Message - From: Don Jones k...@comcast.net To: drakelist@zerobeat.net Sent: Friday, November 19, 2010 11:21 AM Subject: [Drakelist] T-4XC Low Power Output on 160M I have noticed that when loading up my T-4XC up on 160M I am only able to get 45 - 50W out of my transmitter. Seems as though the loading cap has insufficient range for proper tuning. The load control is fully CCW. Is there a problem with the transmitter or does it just need alignment? Thanks 73, Don Jones KO7i Arlington, WA What are you testing into, a dummy load or something else? -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Low Power Output on 160M
There was a mod, I think in Ham Radio magazine, about adding a cap to the pi network on 160M to allow for proper tuning. Anyone know if this might be Don's issue? 73, Ron WD8SBB - Original Message - From: Don Jones k...@comcast.net To: drakelist@zerobeat.net Sent: Friday, November 19, 2010 11:21 AM Subject: [Drakelist] T-4XC Low Power Output on 160M I have noticed that when loading up my T-4XC up on 160M I am only able to get 45 - 50W out of my transmitter. Seems as though the loading cap has insufficient range for proper tuning. The load control is fully CCW. Is there a problem with the transmitter or does it just need alignment? Thanks 73, Don Jones KO7i Arlington, WA ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC VFO Transceive Mode Problem Solved
Thanks for all who responded to my request for info. I have resolved the problem it was the INJ cable and I am good to go. 73, Don Jones Arlington, WA -- Message: 1 Date: Sun, 14 Nov 2010 17:15:43 -0800 From: Don Jones k...@comcast.net To: drakelist@zerobeat.net Subject: [Drakelist] C-line will not go into transceive mode... Strange Message-ID: 002d01cb8462$a0ccf840$e266e8...@net Content-Type: text/plain; charset=us-ascii OK, I have something strange going on. The transceive vfo select on my T-4XC will not switch to one vfo or the other. Running separate is fine. The spot function works good too. The vfo lights on the R-4C and T-4XC switch on off following the vfo select switch position on the T-4XC. A little history, yesterday evening the R-4C was not hearing anything but the calibrator was loud and clear. So today I broke out the Deoxite and cleaned the contacts of the TR relay inside the T-4XC - receive problem solved. I put the T-4XC back together and now I have this new issue with transceive vfo select. I am hoping I did something stupid and easy to fix. 73, Don Jones KO7i -- next part -- An HTML attachment was scrubbed... URL: http://mailman.zerobeat.net/pipermail/drakelist/attachments/20101114/d6160e b0/attachment-0001.html -- Message: 2 Date: Sun, 14 Nov 2010 17:38:28 -0800 (PST) From: Robert Ladden rmlad...@yahoo.com To: drakelist@zerobeat.net Subject: Re: [Drakelist] C-line will not go into transceive mode... Strange Message-ID: 303165.42452...@web43131.mail.sp1.yahoo.com Content-Type: text/plain; charset=utf-8 Let's start with the obvious. ?Is the INJ cable connected well at both ends?Did you put Deox-it on more than the T/R relay? 73,Bob WW3QB --- On Sun, 11/14/10, Don Jones k...@comcast.net wrote: From: Don Jones k...@comcast.net Subject: [Drakelist] C-line will not go into transceive mode... Strange To: drakelist@zerobeat.net Date: Sunday, November 14, 2010, 8:15 PM C-line will not go into transceive mode... Strange OK, I have something strange going on. The transceive vfo select on my T-4XC will not switch to one vfo or the other. Running separate is fine. The spot function works good too. The vfo lights on the R-4C and T-4XC switch on off following the vfo select switch position on the T-4XC. A little history, yesterday evening the R-4C was not hearing anything but the calibrator was loud and clear. So today I broke out the Deoxite and cleaned the contacts of the TR relay inside the T-4XC ? receive problem solved. I put the T-4XC back together and now I have this new issue with transceive vfo select. I am hoping I did something stupid and easy to fix. 73, Don Jones? KO7i -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist -- next part -- An HTML attachment was scrubbed... URL: http://mailman.zerobeat.net/pipermail/drakelist/attachments/20101114/031d09 02/attachment-0001.html -- Message: 3 Date: Sun, 14 Nov 2010 17:42:36 -0800 (PST) From: Bob Loving bob.lov...@sbcglobal.net To: drakelist@zerobeat.net Subject: [Drakelist] Sudden loss of T-4XC ouptut power Message-ID: 744880.82433...@web81103.mail.mud.yahoo.com Content-Type: text/plain; charset=us-ascii I've mentioned this before, rather recently, but check CR19 in the cathode circuit of the driver, V4 (12BY7). I have 2 T-4XC transmitters that exhibited sudden drop (to nothing in both cases) in power output. Both had CR19 with cracks in the cases. The diodes would appear OK with a DMM (diode mode) but with the application of heat would open up. Maybe there's some intermediate mode that would allow moderate output power but that doesn't seem to make too much sense. Most semiconductors work or they don't work, in my experience! A 1N4003 and up is good substitute for the B5G5 diode used by Drake. Bob K9JU -- next part -- An HTML attachment was scrubbed... URL: http://mailman.zerobeat.net/pipermail/drakelist/attachments/20101114/ead943 6e/attachment-0001.html -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist End of Drakelist Digest, Vol 29, Issue 21 * ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output?
Garey, I'm not sure I mentioned this to you or not. When I first realized I was having this trouble with the low output on the TX I heard some kind of a sound when I was tuning up. This was right at the onset of the trouble. After hearing that sound is when I noticed my plate and RF out was way low. Its been like this ever since I heard the sound. I can't really accurately describe it other than a flash or a sizzle. Not sure if it was an arc or what. I don't see anything on the variable capacitors that indicate that an arc occurred. I was not using an amp at the time. Just tuning up barefoot into my DL and at a fairly low power level. Could a component have failed? I'm a little hesitant to attempt an alignment myself. I don't consider myself much of a technician. I will read up on that procedure some more before I give it a go. Also, I am getting the exact same results whether I'm using the RCVR, XMTR, or in separate to tune up. 73 and thanks! -Joe WS8X ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output?
GE Group: Joe: Just my 2 cents here...sudden failures of output are not caused by alignment. It really sounds like a component failure of some sort. The only thing messing with alignment will do for you at this point is mask the solution to real problem. You will get good advice here regarding sorting thru the possible causes and isolating the fault. Don't mess with the alignment. FWIW Curt KU8L 4 Line A and B, TR3 TR4 TR7 and much non-Drake classic equipment. joe loverti wrote: Garey, I'm not sure I mentioned this to you or not. When I first realized I was having this trouble with the low output on the TX I heard some kind of a sound when I was tuning up. This was right at the onset of the trouble. After hearing that sound is when I noticed my plate and RF out was way low. Its been like this ever since I heard the sound. I can't really accurately describe it other than a flash or a sizzle. Not sure if it was an arc or what. I don't see anything on the variable capacitors that indicate that an arc occurred. I was not using an amp at the time. Just tuning up barefoot into my DL and at a fairly low power level. Could a component have failed? I'm a little hesitant to attempt an alignment myself. I don't consider myself much of a technician. I will read up on that procedure some more before I give it a go. Also, I am getting the exact same results whether I'm using the RCVR, XMTR, or in separate to tune up. 73 and thanks! -Joe WS8X ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output?
The first thing that came to my mind was your power supply. Now you have .04 cents. On Sat, Nov 13, 2010 at 6:38 PM, Curt Nixon cptc...@flash.net wrote: GE Group: Joe: Just my 2 cents here...sudden failures of output are not caused by alignment. It really sounds like a component failure of some sort. The only thing messing with alignment will do for you at this point is mask the solution to real problem. You will get good advice here regarding sorting thru the possible causes and isolating the fault. Don't mess with the alignment. FWIW Curt KU8L 4 Line A and B, TR3 TR4 TR7 and much non-Drake classic equipment. joe loverti wrote: Garey, I'm not sure I mentioned this to you or not. When I first realized I was having this trouble with the low output on the TX I heard some kind of a sound when I was tuning up. This was right at the onset of the trouble. After hearing that sound is when I noticed my plate and RF out was way low. Its been like this ever since I heard the sound. I can't really accurately describe it other than a flash or a sizzle. Not sure if it was an arc or what. I don't see anything on the variable capacitors that indicate that an arc occurred. I was not using an amp at the time. Just tuning up barefoot into my DL and at a fairly low power level. Could a component have failed? I'm a little hesitant to attempt an alignment myself. I don't consider myself much of a technician. I will read up on that procedure some more before I give it a go. Also, I am getting the exact same results whether I'm using the RCVR, XMTR, or in separate to tune up. 73 and thanks! -Joe WS8X ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output?
True We're NOT talking about a full alignment here. I merely suggested to Joe that he check the RF and Driver trimmers to be sure they are at least near peak. Information gathered so far, over several days, indicates that there is most likely an RF coupling problem in the Driver and/or PA. The DC voltages on the Driver are good, and the PA idle current is good. It's not yet clear if this is a multi-band problem or not. This last bit of information says that the problem lies in either the Driver or PA stages, and that the DC voltages are correct. This is the first we have heard of the 'sizzle', which often indicates a very high swr, causing 'something' to arc over from the very high peak voltages generated. Possible problems include an RF choke with a shorted turn(s), a capacitor that has broken down, or a simple flash-over from a wire. It seems that the most likely problem area is the coupling into and out of the Driver stage. Again, the PA idle current is ok, just no drive. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: GE Group: Joe: Just my 2 cents here...sudden failures of output are not caused by alignment. It really sounds like a component failure of some sort. The only thing messing with alignment will do for you at this point is mask the solution to real problem. You will get good advice here regarding sorting thru the possible causes and isolating the fault. Don't mess with the alignment. FWIW Curt KU8L 4 Line A and B, TR3 TR4 TR7 and much non-Drake classic equipment. joe loverti wrote: Garey, I'm not sure I mentioned this to you or not. When I first realized I was having this trouble with the low output on the TX I heard some kind of a sound when I was tuning up. This was right at the onset of the trouble. After hearing that sound is when I noticed my plate and RF out was way low. Its been like this ever since I heard the sound. I can't really accurately describe it other than a flash or a sizzle. Not sure if it was an arc or what. I don't see anything on the variable capacitors that indicate that an arc occurred. I was not using an amp at the time. Just tuning up barefoot into my DL and at a fairly low power level. Could a component have failed? I'm a little hesitant to attempt an alignment myself. I don't consider myself much of a technician. I will read up on that procedure some more before I give it a go. Also, I am getting the exact same results whether I'm using the RCVR, XMTR, or in separate to tune up. 73 and thanks! -Joe WS8X ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output?
Joe - More info please Plate current? RF TUNE peak? Other bands? 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com joe loverti wrote: Hello, I'm hoping someone could get me pointed in the right direction with regard to my T-4XC. I've been achieving 100W or above (depending on the band) from the radio consistently in the past. In fact, as recent as a day ago. This afternoon I was tuning up to operate on 80M and now I'm only getting 10W max into a known DL. What would be the cause of this sudden loss of output? Thank you advance! -Joe WS8X St. Louis, MO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output
Thanks to all that have replied in with regard to my T-4XC. All connections have been checked and double checked with no joy. Garey... A little more background and specifics... All was working perfectly fine until I had the bright idea to employ the use of an el cheapo antenna A/B switch to change from my Drakes to my modern rig. I went to tune up w/ the antenna switch in-line and this is when I noticed that my plate current was WAY lower than it normally is. Normally, a the beginning of the tune up sequence (with the XTR gain at 9 o'clock) I get a reading of .2 amperes of plate. After the tune up is complete I usually see the plate at .3 or a little more. Now the most I can muster is .2 amperes. The RF tune has little or no effect. Max out is a little over 10 watts. I was getting over 100 watts easily on all bands before. Could my finals have failed? I am no technician but, it seems like this would have happened more gradually. I am getting plate current, just way down from where it was at. RF tune does peak but, it's way down from where it was. Only about .2 amperes. I've gotten the same results on all the bands that I've tried, 80, 40, and 20. Thanks for the help! -Joe Loverti Jr (WS8X) St. Louis, MO, not Miamisburg, OH A lot of folks get my Dad (WW8X) and I confused ;D ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC sudden loss of RF output
Joe - Perhaps this is too simplistic, but have you removed the switch and gone straight to the dummy load? If you increase the RF GAIN does the plate current / output power increase? 73, Garey - K4OAH Glen Allen, VA joe loverti wrote: Thanks to all that have replied in with regard to my T-4XC. All connections have been checked and double checked with no joy. Garey... A little more background and specifics... All was working perfectly fine until I had the bright idea to employ the use of an el cheapo antenna A/B switch to change from my Drakes to my modern rig. I went to tune up w/ the antenna switch in-line and this is when I noticed that my plate current was WAY lower than it normally is. Normally, a the beginning of the tune up sequence (with the XTR gain at 9 o'clock) I get a reading of .2 amperes of plate. After the tune up is complete I usually see the plate at .3 or a little more. Now the most I can muster is .2 amperes. The RF tune has little or no effect. Max out is a little over 10 watts. I was getting over 100 watts easily on all bands before. Could my finals have failed? I am no technician but, it seems like this would have happened more gradually. I am getting plate current, just way down from where it was at. RF tune does peak but, it's way down from where it was. Only about .2 amperes. I've gotten the same results on all the bands that I've tried, 80, 40, and 20. Thanks for the help! -Joe Loverti Jr (WS8X) St. Louis, MO, not Miamisburg, OH A lot of folks get my Dad (WW8X) and I confused ;D ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC sudden loss of RF output?
Hello, I'm hoping someone could get me pointed in the right direction with regard to my T-4XC. I've been achieving 100W or above (depending on the band) from the radio consistently in the past. In fact, as recent as a day ago. This afternoon I was tuning up to operate on 80M and now I'm only getting 10W max into a known DL. What would be the cause of this sudden loss of output? Thank you advance! -Joe WS8X St. Louis, MO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Mystery
Bob - Cool! Hopefully it had just gone up in value, as carbon comps are wont to do, resulting in t much power. I replace them with a 1W Flameproof or wirewound or ceramic composition. Don't replace with a carbon film or metal film. They don't do well with heavy currents. Glad you found the CD useful. I just wish I had done it 30 years ago. It's depressing to think how many hours of my life I could have saved with it! :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Robert Fish wrote: Hi Gary, Thanks! That was it. R59 fried and in two pieces. I just couldn't see it because it was still in position and appeared to be one piece. No 3.3 ohm resistors in the junk box so I will place an order in the AM. Maybe I will put a 1 watter in there just to increase the margin. Your service CD just paid for itself by saving me time searching for R59. Thanks Again Garey, Bob K6GGO Bob - First thing to check is R59. It has probably gone up in value, causing your meter to read high, and may even be the source of your smoke. Possible heater-cathode short in one of the Final tubes. Also check R132 and R133. You may have had a momentary short from one of the panel lamp socket lugs to chassis. They turn on the socket and can touch the chassis. Beyond that would take a little more investigation. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Robert Fish wrote: Hi Guys, About a month ago I was in a CW QSO using my C-line twins. While transmitting I was getting a little long winded, nothing outrageous, my transmission lasted maybe 1.5 minutes at the most when a quite visible puff of smoke arose from the T-4XC and the panel lights went out. Every thing was dead. I have been fairly busy lately and only now have I had a chance to try and figure out what happened. I opened up the T-4XC and did a visual check top and bottom and could find no discolored or burnt components. I checked the AC-4 and the main fuse (5 amp slo blo) was blown. I replaced the fuse and checked the power supply voltages everything was fine. I put the transmitter on a dummy load and it loads up fine. The power out seems a little light. It seems like I need an awful lot of plate current (nearly 400ma) to get over 100 watts on 40 meters. I didn't keep it at that plate current for very long. I did notice that the neutralization is off a bit. I guess I should do a voltage check and a complete alignment as it hasn't been done in a while. But I am not sure where to start looking for the origin of the smoke. Any ideas as to where I should start looking? Thanks in advance, Bob K6GGO P.S. the 15 ohm cathode resistors are fine ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Mystery
Hi Guys, About a month ago I was in a CW QSO using my C-line twins. While transmitting I was getting a little long winded, nothing outrageous, my transmission lasted maybe 1.5 minutes at the most when a quite visible puff of smoke arose from the T-4XC and the panel lights went out. Every thing was dead. I have been fairly busy lately and only now have I had a chance to try and figure out what happened. I opened up the T-4XC and did a visual check top and bottom and could find no discolored or burnt components. I checked the AC-4 and the main fuse (5 amp slo blo) was blown. I replaced the fuse and checked the power supply voltages everything was fine. I put the transmitter on a dummy load and it loads up fine. The power out seems a little light. It seems like I need an awful lot of plate current (nearly 400ma) to get over 100 watts on 40 meters. I didn't keep it at that plate current for very long. I did notice that the neutralization is off a bit. I guess I should do a voltage check and a complete alignment as it hasn't been done in a while. But I am not sure where to start looking for the origin of the smoke. Any ideas as to where I should start looking? Thanks in advance, Bob K6GGO P.S. the 15 ohm cathode resistors are fine ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Mystery
Bob - First thing to check is R59. It has probably gone up in value, causing your meter to read high, and may even be the source of your smoke. Possible heater-cathode short in one of the Final tubes. Also check R132 and R133. You may have had a momentary short from one of the panel lamp socket lugs to chassis. They turn on the socket and can touch the chassis. Beyond that would take a little more investigation. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Robert Fish wrote: Hi Guys, About a month ago I was in a CW QSO using my C-line twins. While transmitting I was getting a little long winded, nothing outrageous, my transmission lasted maybe 1.5 minutes at the most when a quite visible puff of smoke arose from the T-4XC and the panel lights went out. Every thing was dead. I have been fairly busy lately and only now have I had a chance to try and figure out what happened. I opened up the T-4XC and did a visual check top and bottom and could find no discolored or burnt components. I checked the AC-4 and the main fuse (5 amp slo blo) was blown. I replaced the fuse and checked the power supply voltages everything was fine. I put the transmitter on a dummy load and it loads up fine. The power out seems a little light. It seems like I need an awful lot of plate current (nearly 400ma) to get over 100 watts on 40 meters. I didn't keep it at that plate current for very long. I did notice that the neutralization is off a bit. I guess I should do a voltage check and a complete alignment as it hasn't been done in a while. But I am not sure where to start looking for the origin of the smoke. Any ideas as to where I should start looking? Thanks in advance, Bob K6GGO P.S. the 15 ohm cathode resistors are fine ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Mystery
Hi Gary, Thanks! That was it. R59 fried and in two pieces. I just couldn't see it because it was still in position and appeared to be one piece. No 3.3 ohm resistors in the junk box so I will place an order in the AM. Maybe I will put a 1 watter in there just to increase the margin. Your service CD just paid for itself by saving me time searching for R59. Thanks Again Garey, Bob K6GGO Bob - First thing to check is R59. It has probably gone up in value, causing your meter to read high, and may even be the source of your smoke. Possible heater-cathode short in one of the Final tubes. Also check R132 and R133. You may have had a momentary short from one of the panel lamp socket lugs to chassis. They turn on the socket and can touch the chassis. Beyond that would take a little more investigation. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Robert Fish wrote: Hi Guys, About a month ago I was in a CW QSO using my C-line twins. While transmitting I was getting a little long winded, nothing outrageous, my transmission lasted maybe 1.5 minutes at the most when a quite visible puff of smoke arose from the T-4XC and the panel lights went out. Every thing was dead. I have been fairly busy lately and only now have I had a chance to try and figure out what happened. I opened up the T-4XC and did a visual check top and bottom and could find no discolored or burnt components. I checked the AC-4 and the main fuse (5 amp slo blo) was blown. I replaced the fuse and checked the power supply voltages everything was fine. I put the transmitter on a dummy load and it loads up fine. The power out seems a little light. It seems like I need an awful lot of plate current (nearly 400ma) to get over 100 watts on 40 meters. I didn't keep it at that plate current for very long. I did notice that the neutralization is off a bit. I guess I should do a voltage check and a complete alignment as it hasn't been done in a while. But I am not sure where to start looking for the origin of the smoke. Any ideas as to where I should start looking? Thanks in advance, Bob K6GGO P.S. the 15 ohm cathode resistors are fine ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC issues
Hey everyone, still trying to sort out the new to me Drake twins. Replaced caps in RX/TX, installed new finals in TX. PS rebuilt using Heathkit Shop's kit. Final tubes test 100% ouput. Having trouble loading up transmit. On 80 meters, only getting about 20 watts out. 10 meters, the output goes up to about 150 watts out, and is in oscillation. Output goes up from the low bands to the oscillation/high output state on the high bands. Power will hold at normal on 20 meters, but then bam! goes into oscillation. Testing is being done into a dummy load. Can someone point me in the right direction as to what is wrong? Tnx and 73, Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC issues
Brett - Are the Final tubes the same brand? What brand are they? Have you done the Final neutralization? Section 5-10 in the manual. Does the RF TUNE peak in the right areas of the scale? 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Brett Forehand wrote: Hey everyone, still trying to sort out the new to me Drake twins. Replaced caps in RX/TX, installed new finals in TX. PS rebuilt using Heathkit Shop's kit. Final tubes test 100% ouput. Having trouble loading up transmit. On 80 meters, only getting about 20 watts out. 10 meters, the output goes up to about 150 watts out, and is in oscillation. Output goes up from the low bands to the oscillation/high output state on the high bands. Power will hold at normal on 20 meters, but then bam! goes into oscillation. Testing is being done into a dummy load. Can someone point me in the right direction as to what is wrong? Tnx and 73, Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Bias
Have good bias (-55 adjustable up - or down - to -75V) at rear plug - and on PS sub board, but nothing getting to finals - any good ideas where to look first? Michael W7HUT ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Bias
Michael - Shorted V1, shorted C63. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Michael Ditmore wrote: Have good bias (-55 adjustable up - or down - to -75V) at rear plug - and on PS sub board, but nothing getting to finals - any good ideas where to look first? Michael W7HUT ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC carrier in the R-4C receiver
I recently acquired a R-4C receiver and T-4XC and the transmitter has a problem. With power applied to it after warm up the meter on transmitter will go negative to the left of zero and i get a carrier in the receiver at about 60 db on the same frequency on both VFO's. checked all tubes and they seem to be OK. The carrier will change in amplitude with tuning of the final tank for max output. Could someone give me an idea on what to do to trouble shoot it. Rex Meier KQ0Z Love Spell Click here to light up your life with a love spell! http://thirdpartyoffers.juno.com/TGL2131/c?cp=CH0uhEhY-Fy2WuECIAwM2gAAJz0UFYKTAyySMiC3nbWXP64QAAYAAADNRwA= ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC carrier in the R-4C receiver
Sounds like the Bias supply may have failed, or be failing. Have you been able to set the transmitter idle current per the manual?. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com k...@juno.com wrote: I recently acquired a R-4C receiver and T-4XC and the transmitter has a problem. With power applied to it after warm up the meter on transmitter will go negative to the left of zero and i get a carrier in the receiver at about 60 db on the same frequency on both VFO's. checked all tubes and they seem to be OK. The carrier will change in amplitude with tuning of the final tank for max output. Could someone give me an idea on what to do to trouble shoot it. Rex Meier KQ0Z ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC carrier in the R-4C receiver
If the bias is ok, then Check the screen resistors on the final tubes. These resistors occasionally fail. Note: most tube checkers do not have the current to check a 6jb6 accurately. Good luck. David Assaf, III From W5XU Desktop -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Garey Barrell Sent: Saturday, January 23, 2010 12:04 PM To: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4XC carrier in the R-4C receiver Sounds like the Bias supply may have failed, or be failing. Have you been able to set the transmitter idle current per the manual?. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com k...@juno.com wrote: I recently acquired a R-4C receiver and T-4XC and the transmitter has a problem. With power applied to it after warm up the meter on transmitter will go negative to the left of zero and i get a carrier in the receiver at about 60 db on the same frequency on both VFO's. checked all tubes and they seem to be OK. The carrier will change in amplitude with tuning of the final tank for max output. Could someone give me an idea on what to do to trouble shoot it. Rex Meier KQ0Z ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.730 / Virus Database: 271.1.1/2640 - Release Date: 01/23/10 01:33:00 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC slugs
I am in the process of rebuilding a T-4XC transmitter, before I test this, I noticed that the slug on T6 grid coil has been wound in somewhat, now I assume this has been done by some misguided person as I am thinking all of these should be the same height? I refered to the manual and it says about various dot colours, cannot see any coloured dots so maybe mine are no dot? Also resistor r90 47k and the diode cr19 on V4 driver were both fried, any ideas why these should pop? might give me an idea what to look for on switch on. 73 Max M0GHQ/KJ4ISS -- I am using the free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 2322 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len The Professional version does not have this message ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC slugs +
I can also see that T1 has been damaged at some point maybe this is having an influence on T6? I am in the process of rebuilding a T-4XC transmitter, before I test this, I noticed that the slug on T6 grid coil has been wound in somewhat, now I assume this has been done by some misguided person as I am thinking all of these should be the same height? I refered to the manual and it says about various dot colours, cannot see any coloured dots so maybe mine are no dot? Also resistor r90 47k and the diode cr19 on V4 driver were both fried, any ideas why these should pop? might give me an idea what to look for on switch on. 73 Max M0GHQ/KJ4ISS -- I am using the Free version of SPAMfighter. We are a community of 6 million users fighting spam. SPAMfighter has removed 2322 of my spam emails to date. The Professional version does not have this message. -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.730 / Virus Database: 270.14.149/2630 - Release Date: 01/18/10 07:35:00 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R4-C Serial numbers
Hi, Brett. And thanks, Don. Yes, we stock individual can-caps and complete re-cap kits for most Drake units, including your transmitter and receiver. You can order them online at www.hayseedhamfest.com/capkit.htm . For the AC-3 and AC-4, definitely check out Mike Bryce's p.s. rebuild/upgrade units at www.theheathkitshop.com. They are superb. 73, Tom NØJMY . . Hayseed Hamfest Co. - Multi-section Can Capacitors for vintage Heathkit, Drake, Halli, Hammy, more... www.hayseedhamfest.com Don Cunningham wrote: Brett, I can't answer your serial number questions, but can recommend very good sources for the cap kits. For the transmitter/receiver try www.hayseedhamfest.com http://www.hayseedhamfest.com . Tom has the multisection caps and a reasonable price on the total cap kits. For the power supply, see www.theheathkitshop.com http://www.theheathkitshop.com and look at Mike's AC4R kit. That should put the rigs in fine shape. Maybe Garey can chime in with the serial number answer, hi. 73, Don, WB5HAK - Original Message - *From:* Brett Forehand mailto:brett_foreh...@yahoo.com *To:* drakelist@zerobeat.net mailto:drakelist@zerobeat.net *Sent:* Sunday, October 11, 2009 7:57 PM *Subject:* [Drakelist] T-4XC/R4-C Serial numbers Hey folks... just looking at serial numbers and wondering about what differences there are in models/years made. My receiver's serial number is 25743, and the transmitter is 28390. Interested in buying cap kits for both the tx and rx. Power supply too! Thanks, Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.421 / Virus Database: 270.14.10/2429 - Release Date: 10/11/09 18:34:00 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC/R4-C Serial numbers
Hey folks... just looking at serial numbers and wondering about what differences there are in models/years made. My receiver's serial number is 25743, and the transmitter is 28390. Interested in buying cap kits for both the tx and rx. Power supply too! Thanks,Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
Wow! Not sure how to respond to everyone... had no idea this list was THIS active. Thanks to all who answered. My apologies to everyone for not getting in here sooner... I work 12 hour shifts, and also had a plumbing problem at my house. With that being said, I have read and re-read the manual regarding tune-up. Tuning per the manual, I am getting max 20 watts on 20 and 40 (maximum gain on the transmitter). Running at the recommended 11 o'clock setting on the gain, I only see about 5-10 watts out. I am not sure if my Kenwood tuner/watt meter is PEP or not, but that's the power it shows. The lights on the transmitter do not dim whatsoever, which I think I could expect if the PS was weak. I am going to look at the final tubes (I can get a matched NOS pair pretty cheap) and see if that might be it. 12BY7 (I think?) was replaced with no change in output. Supposedly, this rig was run almost daily until about 4 months ago. Sadly, the previous owner is now a silent key. I'm not going to fiddle with tuning pots and such until I can sort out the simple stuff. And even then, it will probably be shipped off to a competent tech. Thanks to all who answered and provided guidance. I really appreciate it! I'll keep everyone posted as I make any progress. 73,Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
okay only did a reply instead of reply all. Please read before twiddling with the rack trimmers. --- On Wed, 8/26/09, Ron wd8...@yahoo.com wrote: From: Ron wd8...@yahoo.com Subject: Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: Brett Forehand brett_foreh...@yahoo.com Date: Wednesday, August 26, 2009, 8:08 PM OMG! DON'T be screwing with the trimmers on the side of the rack for a reading like this! First question is; is the power meter reading average or peak power? If average, this is actually normal. This rig does not have compression built in, so you will only see a very low average power. A peak reading power meter should show about 100 or so watts. Try this first. In TUNE, what can you get on power output. That should be about 90-100 watts on most bands. CW will drive a bit more, for what reason I am not sure. If this power is not obtained, first check voltages on the power supply. Next most likely thing is tubes. At least this is my opinion. 73, Ron WD8SBB --- On Tue, 8/25/09, Brett Forehand brett_foreh...@yahoo.com wrote: From: Brett Forehand brett_foreh...@yahoo.com Subject: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: drakelist@zerobeat.net Date: Tuesday, August 25, 2009, 5:21 PM Hello folks, I'm new to the group and new to a Drake twins set. Receive seems to be working well after using a LOT of deoxit. Knocked all the crispy/scratchiness out of all the controls. BTO is working smoothly. The noise blanker is phenomenal. Getting the nicotine off of the front panel revealed a real nice face on both the transmitter and the receiver. Using a hand me down G5RV, which I know is not the best, but seems to pull in signals very well. I am not getting much output (5-10 watts on SSB) on 20 and 40. I have VERY little output according to the transmitter meter, the watt meter I'm using is an outboard Kenwood. I could just leave it alone and call it a QRP rig, I guess! ;) I was wondering if the bias setting on the PS could be set wrong? Or am I to assume since there is not much output when tuning/loading, (below .1 ma, actually at the little notch on the top side of the meter) that the power supply is soft? I have seen the cap replacement/upgrade board for these supplies, and am considering getting one. Any suggestions to point me the right direction are greatly appreciated. I am a total newbie at this, and can use all the help I can get. Thanks and 73,Brett -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC/R-4C/AC-4 low power questions
Hello folks, I'm new to the group and new to a Drake twins set. Receive seems to be working well after using a LOT of deoxit. Knocked all the crispy/scratchiness out of all the controls. BTO is working smoothly. The noise blanker is phenomenal. Getting the nicotine off of the front panel revealed a real nice face on both the transmitter and the receiver. Using a hand me down G5RV, which I know is not the best, but seems to pull in signals very well. I am not getting much output (5-10 watts on SSB) on 20 and 40. I have VERY little output according to the transmitter meter, the watt meter I'm using is an outboard Kenwood. I could just leave it alone and call it a QRP rig, I guess! ;) I was wondering if the bias setting on the PS could be set wrong? Or am I to assume since there is not much output when tuning/loading, (below .1 ma, actually at the little notch on the top side of the meter) that the power supply is soft? I have seen the cap replacement/upgrade board for these supplies, and am considering getting one. Any suggestions to point me the right direction are greatly appreciated. I am a total newbie at this, and can use all the help I can get. Thanks and 73,Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
There are small tuning caps on the T4XC and R4C as I recall on the side of each one, to tweak output on each band using each independent PTO. I believe there are three for each band. With a watt meter and dummy load.. incrementally adjust these for about 100 watts output... not more..if you can only get 80 to 90 watts out on a band particularly 15 or 10 meters that's fine. You must remove as I recall both the top and bottom covers of each, the T4XC and R4C...to get to this small tinning caps on the side of the rigs. 73 Tim wb8uhz --- On Tue, 8/25/09, Brett Forehand brett_foreh...@yahoo.com wrote: From: Brett Forehand brett_foreh...@yahoo.com Subject: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: drakelist@zerobeat.net Date: Tuesday, August 25, 2009, 5:21 PM Hello folks, I'm new to the group and new to a Drake twins set. Receive seems to be working well after using a LOT of deoxit. Knocked all the crispy/scratchiness out of all the controls. BTO is working smoothly. The noise blanker is phenomenal. Getting the nicotine off of the front panel revealed a real nice face on both the transmitter and the receiver. Using a hand me down G5RV, which I know is not the best, but seems to pull in signals very well. I am not getting much output (5-10 watts on SSB) on 20 and 40. I have VERY little output according to the transmitter meter, the watt meter I'm using is an outboard Kenwood. I could just leave it alone and call it a QRP rig, I guess! ;) I was wondering if the bias setting on the PS could be set wrong? Or am I to assume since there is not much output when tuning/loading, (below .1 ma, actually at the little notch on the top side of the meter) that the power supply is soft? I have seen the cap replacement/upgrade board for these supplies, and am considering getting one. Any suggestions to point me the right direction are greatly appreciated. I am a total newbie at this, and can use all the help I can get. Thanks and 73,Brett -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
also, use an INSULATED screwdriver for these on the left side of the chassis. If you use a metal one and it touches the chassis while you are making adjustments, it can short stuff out. Chuck, K1OM On Tue, Aug 25, 2009 at 6:12 PM, amfone amfone20...@yahoo.com wrote: There are small tuning caps on the T4XC and R4C as I recall on the side of each one, to tweak output on each band using each independent PTO. I believe there are three for each band. With a watt meter and dummy load.. incrementally adjust these for about 100 watts output... not more..if you can only get 80 to 90 watts out on a band particularly 15 or 10 meters that's fine. You must remove as I recall both the top and bottom covers of each, the T4XC and R4C...to get to this small tinning caps on the side of the rigs. 73 Tim wb8uhz --- On *Tue, 8/25/09, Brett Forehand brett_foreh...@yahoo.com* wrote: From: Brett Forehand brett_foreh...@yahoo.com Subject: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: drakelist@zerobeat.net Date: Tuesday, August 25, 2009, 5:21 PM Hello folks, I'm new to the group and new to a Drake twins set. Receive seems to be working well after using a LOT of deoxit. Knocked all the crispy/scratchiness out of all the controls. BTO is working smoothly. The noise blanker is phenomenal. Getting the nicotine off of the front panel revealed a real nice face on both the transmitter and the receiver. Using a hand me down G5RV, which I know is not the best, but seems to pull in signals very well. I am not getting much output (5-10 watts on SSB) on 20 and 40. I have VERY little output according to the transmitter meter, the watt meter I'm using is an outboard Kenwood. I could just leave it alone and call it a QRP rig, I guess! ;) I was wondering if the bias setting on the PS could be set wrong? Or am I to assume since there is not much output when tuning/loading, (below .1 ma, actually at the little notch on the top side of the meter) that the power supply is soft? I have seen the cap replacement/upgrade board for these supplies, and am considering getting one. Any suggestions to point me the right direction are greatly appreciated. I am a total newbie at this, and can use all the help I can get. Thanks and 73, Brett -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mc/compose?to=drakel...@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
Yes on the insulated screwdriver Chuck.. 73 tim wb8uhz --- On Tue, 8/25/09, Chuck Grandgent ch...@chuckg.com wrote: From: Chuck Grandgent ch...@chuckg.com Subject: Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: amfone amfone20...@yahoo.com Cc: drakelist@zerobeat.net, Brett Forehand brett_foreh...@yahoo.com Date: Tuesday, August 25, 2009, 6:48 PM also, use an INSULATED screwdriver for these on the left side of the chassis. If you use a metal one and it touches the chassis while you are making adjustments, it can short stuff out. Chuck, K1OM On Tue, Aug 25, 2009 at 6:12 PM, amfone amfone20...@yahoo.com wrote: There are small tuning caps on the T4XC and R4C as I recall on the side of each one, to tweak output on each band using each independent PTO. I believe there are three for each band. With a watt meter and dummy load.. incrementally adjust these for about 100 watts output... not more..if you can only get 80 to 90 watts out on a band particularly 15 or 10 meters that's fine. You must remove as I recall both the top and bottom covers of each, the T4XC and R4C...to get to this small tinning caps on the side of the rigs. 73 Tim wb8uhz --- On Tue, 8/25/09, Brett Forehand brett_foreh...@yahoo.com wrote: From: Brett Forehand brett_foreh...@yahoo.com Subject: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: drakelist@zerobeat.net Date: Tuesday, August 25, 2009, 5:21 PM Hello folks, I'm new to the group and new to a Drake twins set. Receive seems to be working well after using a LOT of deoxit. Knocked all the crispy/scratchiness out of all the controls. BTO is working smoothly. The noise blanker is phenomenal. Getting the nicotine off of the front panel revealed a real nice face on both the transmitter and the receiver. Using a hand me down G5RV, which I know is not the best, but seems to pull in signals very well. I am not getting much output (5-10 watts on SSB) on 20 and 40. I have VERY little output according to the transmitter meter, the watt meter I'm using is an outboard Kenwood. I could just leave it alone and call it a QRP rig, I guess! ;) I was wondering if the bias setting on the PS could be set wrong? Or am I to assume since there is not much output when tuning/loading, (below .1 ma, actually at the little notch on the top side of the meter) that the power supply is soft? I have seen the cap replacement/upgrade board for these supplies, and am considering getting one. Any suggestions to point me the right direction are greatly appreciated. I am a total newbie at this, and can use all the help I can get. Thanks and 73,Brett -Inline Attachment Follows- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
Hi Brett, You may have lost one of the diodes in a voltage doubler section in the power supply, thus getting about half voltage. What does your wattmeter show in tune position, or on CW? If it's low, suspect the p.s., or possibly the plate dropping resistor in the buffer (12BY7) in the T-4XC. Also check the cathode screen resistors for both of the final tubes. They should be within 10% of nominal. Don't mess with adjustments until you've checked those things. Can you set idle current properly at 70 ma.? If not, change the electrolytic filter caps in the bias section of the supply. They are the gotchas in the whole thing, if they go, your transmitter can go on and fry the fnals, when you're not even there, if it's powered up. The VOX triggers and a ripple in the bias supply drives the finals full tilt to destruction. It happens in seconds. 73, Al, W8UT New Bern, NC www.boatanchors.org www.hammarlund.info there is nothing -absolutely nothing- half as much worth doing as simply messing about in boats. Ratty, to Mole - Original Message - From: Brett Forehand brett_foreh...@yahoo.com To: drakelist@zerobeat.net Sent: Tuesday, August 25, 2009 5:21 PM Subject: [Drakelist] T-4XC/R-4C/AC-4 low power questions Hello folks, I'm new to the group and new to a Drake twins set. Receive seems to be working well after using a LOT of deoxit. Knocked all the crispy/scratchiness out of all the controls. BTO is working smoothly. The noise blanker is phenomenal. Getting the nicotine off of the front panel revealed a real nice face on both the transmitter and the receiver. Using a hand me down G5RV, which I know is not the best, but seems to pull in signals very well. I am not getting much output (5-10 watts on SSB) on 20 and 40. I have VERY little output according to the transmitter meter, the watt meter I'm using is an outboard Kenwood. I could just leave it alone and call it a QRP rig, I guess! ;) I was wondering if the bias setting on the PS could be set wrong? Or am I to assume since there is not much output when tuning/loading, (below .1 ma, actually at the little notch on the top side of the meter) that the power supply is soft? I have seen the cap replacement/upgrade board for these supplies, and am considering getting one. Any suggestions to point me the right direction are greatly appreciated. I am a total newbie at this, and can use all the help I can get. Thanks and 73,Brett ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions
Yes, and do not tighten any of them too tight, the mica can fracture and they'll short out just like with a screwdriver. (if they need to be tight, something else is wrong.) Al, W8UT - Original Message - From: amfone amfone20...@yahoo.com To: Chuck Grandgent ch...@chuckg.com Cc: Brett Forehand brett_foreh...@yahoo.com; drakelist@zerobeat.net Sent: Tuesday, August 25, 2009 7:05 PM Subject: Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions Yes on the insulated screwdriver Chuck.. 73 tim wb8uhz --- On Tue, 8/25/09, Chuck Grandgent ch...@chuckg.com wrote: From: Chuck Grandgent ch...@chuckg.com Subject: Re: [Drakelist] T-4XC/R-4C/AC-4 low power questions To: amfone amfone20...@yahoo.com Cc: drakelist@zerobeat.net, Brett Forehand brett_foreh...@yahoo.com Date: Tuesday, August 25, 2009, 6:48 PM also, use an INSULATED screwdriver for these on the left side of the chassis. If you use a metal one and it touches the chassis while you are making adjustments, it can short stuff out. Chuck, K1OM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Housing Paint
Hello, all. I am new to the Drakelist but have been an owner of one or more pieces of RL Drake equipment since 1963. My R-4 is serial number 0065 but I redesigned and solid stated it over the course of many years. My question pertains to a T-4XC (s/n 25745) and MS-4 (w/AC-4) that purchased at a recent hamfest (for a very good price): Did RL Drake ever ship any radios or accessories in the 4-line with a semiflat black crinkle-like finish? That is the finish on the cabinets of the T-4XC and MS-4, not the splotchy semiflat black of my other T-4XC and R-4C. The finish looks very professional if it was done aftermarket. Thank you to all who post to the Drakelist the myriad of suggestions for repairing and maintaining these wonderful pieces of equipment. This particular T-4XC had low power output, ~50 W, and a different setof 6JB6s brought it up to specification. 73, Bob K9JU Streamwood, IL ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC Problem
Hi Guys, My T-4XC has stopped transmitting. I have normal idle current. But not much more. If I turn the gain way up I can get a barely perceptible dip in plate current.90 or 100 ma. So I turned the bias voltage all the way down and put it in tune very briefly to see if the finals were at least functional. I get about 260ma when I do that. I presume this means they still work? It looks like I have lost drive somewhere. I checked the carrier oscillator and it is up and running, I can see it with a scope and a freq counter. However, I don't see my 5.645 Mhz at the plate of V2 (IF amp). I did a voltage check and all of the voltages on V2 look normal. Then I did a resistance check on V2. I found everything normal except the cathode measures 5.5k to ground. The book says it should measure infinite. Is this potentially my problem or is this non critical. I thought I would see if you guys think I am on the right track before I start lifting one leg of every cap in that circuit. Thanks, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Problem
My guess is the bias supply caps are probably bad and you are getting AC on the bias which does not show up on the meter. (The peak AC volts are masking your DC set point). At least replace the bias electrolytics, but why not just put in an AC-4R board with all new parts including all the electrolytics. Lee, w0vt - Original Message - From: Bob Fish rwf...@comcast.net To: drakelist@zerobeat.net Sent: Thursday, May 07, 2009 2:02 PM Subject: [Drakelist] T-4XC Problem Hi Guys, My T-4XC has stopped transmitting. I have normal idle current. But not much more. If I turn the gain way up I can get a barely perceptible dip in plate current.90 or 100 ma. So I turned the bias voltage all the way down and put it in tune very briefly to see if the finals were at least functional. I get about 260ma when I do that. I presume this means they still work? It looks like I have lost drive somewhere. I checked the carrier oscillator and it is up and running, I can see it with a scope and a freq counter. However, I don't see my 5.645 Mhz at the plate of V2 (IF amp). I did a voltage check and all of the voltages on V2 look normal. Then I did a resistance check on V2. I found everything normal except the cathode measures 5.5k to ground. The book says it should measure infinite. Is this potentially my problem or is this non critical. I thought I would see if you guys think I am on the right track before I start lifting one leg of every cap in that circuit. Thanks, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC Problem
Sorry, didn't read your second paragraph. Lee, w0vt - Original Message - From: Bob Fish rwf...@comcast.net To: drakelist@zerobeat.net Sent: Thursday, May 07, 2009 2:02 PM Subject: [Drakelist] T-4XC Problem Hi Guys, My T-4XC has stopped transmitting. I have normal idle current. But not much more. If I turn the gain way up I can get a barely perceptible dip in plate current.90 or 100 ma. So I turned the bias voltage all the way down and put it in tune very briefly to see if the finals were at least functional. I get about 260ma when I do that. I presume this means they still work? It looks like I have lost drive somewhere. I checked the carrier oscillator and it is up and running, I can see it with a scope and a freq counter. However, I don't see my 5.645 Mhz at the plate of V2 (IF amp). I did a voltage check and all of the voltages on V2 look normal. Then I did a resistance check on V2. I found everything normal except the cathode measures 5.5k to ground. The book says it should measure infinite. Is this potentially my problem or is this non critical. I thought I would see if you guys think I am on the right track before I start lifting one leg of every cap in that circuit. Thanks, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4XC relay won't go to transmit
Hello everyone, I just got a C line to add to my B line. Love this stuff. The problem: The relay in the T-4XC will not switch to transmit. Background: The T-4XC was working when I got it, althought the switches needed to be cleaned; I could tell by the meter bouncing around and by noise made in the receiver when switching. I cleaned the switches and checked the tubes while I was at it. I put it back in line and things were fine for a while. Then, without smoke, sparks, or any other fanfare, the relay stopped doing its job. This was shortly after I plugged in a mic. To eliminate any possible suspicion of the power supply, I tried the AC-4 from the B line. No chnage (still not working). If it makes any difference, the serial number is 21,000+ (forgot the last 3 digits). Question: Would the relay just up and fail like that? I looked through the archives and note that relays do need replacing at times. But, before I order one (and thank for having the Mouser number there in a 1/2007 post), could the cause be elsewhere? Thanks, Jim ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4XC relay won't go to transmit
Do you have the schematic for the T-4XC? If so you can trace through the keying circuit to see if the relay is getting the proper voltage to pull it in. Also you can measure its resistance to see if it is open first before you start doing some circuit troubleshooting. Jim - Original Message - From: J G To: drakelist@zerobeat.net Sent: Thursday, March 19, 2009 4:00 PM Subject: [Drakelist] T-4XC relay won't go to transmit Hello everyone, I just got a C line to add to my B line. Love this stuff. The problem: The relay in the T-4XC will not switch to transmit. Background: The T-4XC was working when I got it, althought the switches needed to be cleaned; I could tell by the meter bouncing around and by noise made in the receiver when switching. I cleaned the switches and checked the tubes while I was at it. I put it back in line and things were fine for a while. Then, without smoke, sparks, or any other fanfare, the relay stopped doing its job. This was shortly after I plugged in a mic. To eliminate any possible suspicion of the power supply, I tried the AC-4 from the B line. No chnage (still not working). If it makes any difference, the serial number is 21,000+ (forgot the last 3 digits). Question: Would the relay just up and fail like that? I looked through the archives and note that relays do need replacing at times. But, before I order one (and thank for having the Mouser number there in a 1/2007 post), could the cause be elsewhere? Thanks, Jim -- ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
