Re: [Drakelist] R-4C IC Product Detector
Byron: we;lcome to the adventure! The 8 KC front end filter is very broad. The previous owner must have been an AM SWL? Please read Sherwood's and Inrad's info on the roofing filter for the radio. The r4c is the radio where the concept of the roofing filter was made back in the 1970's. It transforms a so so radio to a great one. Drake's r4c, stock, was actually a step backwards in performance. Many still claim the B line superior. Modified, as you are doing will erase that doubt. The power supply is a necessary mod. drake simply had one big power supply and when they needed a different voltage they used large resistors. With age, these resistors change and you end up not knowing the actual voltage. The audio and product detectors are a small increment in the performance of the radio. Please consider Sherwood's third mixer mod. I chased the noise in mine till I read his article and it was the second best thing I did for mine (the roofing filters were the first). Cannot tell you the number of third mixer tubes I tried to make the receiver quiet,. Drake had three or four third mixers in the radio. They were aware of the noise, technology was not there to fix it. It is now. I would not pull off the 10 volts on the Balanced modulator. I would do the 12 volts you need from a separate regulator at the power supply. Look at Sherwood's power supply mod. It is all you need for any mod in the radio. The solid state mixer noted above will need that 12 volts as well. One last thing if you do CW. Look into the AGC mod offered by Sherwood. It is well worth the considerable trouble to do. Good Luck! David Assaf, III W5XU On Sun, Mar 31, 2013 at 8:53 PM, Byron Tatum wrote: > Hello- > I am in the process of installing some upgrades in my R-4C, an early > one (18K SN range) that has the 6HS6's. The INRAD 8 KC 5645 KC first > IF filter was in when I bought it, so at least I have a little bit of > protection for that second mixer. > I upgraded the power supply with the 7812 regulator and better > electrolytic caps all around, per WB4HFN info combined with Sherwood info. > Today I built the IC product detector using a TL442CN, installed it > and appears all is well. I thought I would post this as I believe the > TL442CN is an obsolete device. The TI SN76514 is an identical chip, it was > used in the Mihuzo 9 Mhz SSB boards as the balanced modulator. One thing, I > am powering mine fom the +10 VDC that is provided for BFO, as that terminal > was very near the module. Is itnecessary to have the full 12 VDC on the > chip? > I wish to do the sudio amp upgrade, mostly to get rid of the heat, but > also to have a little better audio. I am thinking of going with the LM383T > as done by Sherwood, but saw a video of an R-4C sporting a "D-Labs" audio > upgrade. I cannot find any additional info on this. Thought I would ask for > advice before I proceeded with the audio changes. > Thanks, Byron WA5THJ > > ___ > 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] Returning to ham radio and considering a TR-7. Recommendations?
agree with the comments. At hamfests a great one goes for 650 to 750 with all the filters. Ebay is all over the place. Might want to also try eham. Good luck and welcome back! David Assaf, III W5XU On Fri, Mar 22, 2013 at 4:57 PM, Mark Nace wrote: > Good for you Tom ! > I would look for a later serial number TR-7, with the "A" type features. > It may > even be labeled a TR-7A. Anyway, it is a great rig. I started with a > used one > about 26 years ago, and mine is still going strong (a little TLC over the > years > has kept it that way!). the serial number is in the 8600's, and had the > "A" > items already in it. The ones on ebay right now are pretty neat, but one > looks > like it is a lower serial number. They are VERY functional rigs actually, > and > don't have all the bells and whistles of todays rigs, but most of that > stuff > doesn't have much to do with catching the rare DX, or doing a great job of > constesting !!! > > Best 73 > Mark > N5KAE > > > > - Original Message > > From: Tom Branton > > To: "drakelist@zerobeat.net" > > Sent: Fri, March 22, 2013 4:43:25 PM > > Subject: [Drakelist] Returning to ham radio and considering a TR-7. > >Recommendations? > > > > > > > > Good afternoon everyone, > > > > After a long absence from ham radio I am excited about re-entering the > hobby > >and I am interested in acquiring a TR-7. It was my dream radio when > career took > >me away from the hobby. > > > > Any words of wisdom you may have about the TR-7 would be most welcome. > > Is there anything I should particularly look for in a potential > purchase? Any > >thoughts > > on what a TR-7 and power supply in good condition would cost? There is > what > >appears to be a very nice one listed on EBay at > > the moment. > > > > Thanks and 73's > > > > Tom > > Ex WD5DFE > > > > > > > > > > ___ > > 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] Questioin re: Drake 2NT final Tube replacement
Many forget the sweep tubes were used as the horizontal output tubes in TV sets. They ran hours at max conditions. Unfortunately when they are used in ham sets, the ability to exceed the grid and plate currents when tuning gave these fine devices a bad wrap. If you follow the book and tune as asked, they will last a long time. As to your question, the bias for the tubes are manufacturer sensitive. As Drake used mostly Sylvania tubes, they suggest to reuse the same. David Assaf, III W5XU On Thu, Mar 21, 2013 at 1:40 PM, Charles Ring wrote: > I've always questioned Drake's decision to use the 6HF5 in that > transmitter. Sweep tubes made some sense for SSB at the time, but a CW > transmitter meant for beginners? A 6146 would have been so much more > forgiving and reliable. > > 73 de W3NU > > > > On 3/21/2013 1341, Curt Gidding wrote: > > The manual suggests that the final 6HF5 be replaced with the same > manufacturer tube as > is in the xmtr. How critical is this? Is there one manufacturer that is > better? Tnx for your > reply. > > Curt Gidding KC9UNL > > > > ___ > 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] Drakelist Digest, Vol 54, Issue 10 TR 3
Incidentially and as you may wish, there is an old circuit that is simple and effective to add CW break in for a tr3. Did it 3 times and worked very well. I beleive it is an old article in CQ mag. On Tue, Dec 11, 2012 at 9:34 PM, Bill skidmore wrote: > The comment about the sideband filter in the TR 3 is not to be passed over > lightly. If you have a problem there, you are in deep trouble. I carefully > took the surrounding shield off my problem filter and repaired it, then put > it together again. I was lucky I didn't break something. > > All the other comments, concerning historic equipment, TR 3 as a poor CW > rig, etc, are spot on. > Buy it anyway! These things keep us from going brain dead using multi-band > CB equipment. > > 73, Bill, VE3AUI > On 2012-12-12 3:28 AM, wrote: > >> Send Drakelist mailing list submissions to >> drakelist@zerobeat.net >> >> To subscribe or unsubscribe via the World Wide Web, visit >> http://mailman.zerobeat.net/mailman/listinfo/drakelist >> or, via email, send a message with subject or body 'help' to >> drakelist-requ...@zerobeat.net >> >> You can reach the person managing the list at >> drakelist-ow...@zerobeat.net >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of Drakelist digest..." >> >> >> Today's Topics: >> >>1. Re: TR-3 (Al Parker) >>2. Re: TR-3 (Lee Hiers) >>3. Re: TR-3 (John King) >>4. Re: TR-3 (David Assaf III) >> >> >> -- >> >> Message: 1 >> Date: Tue, 11 Dec 2012 14:17:35 -0500 >> From: Al Parker >> To: lane denune >> Cc: "drakelist@zerobeat.net" >> Subject: Re: [Drakelist] TR-3 >> Message-ID: <50c786cf.60...@ec.rr.com> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> Hi, >> The deal "killer" in the TR-3 is the SB filter. They often go >> bad on >> one sideband, still get some thru, but way low. Check output on 20m and >> on 15m, they should be close, and above 125 watts out. Actual value >> could be more (hopefully), but will depend upon alignment. Normally 15m >> output will be a little less than on 20m, but not more than say 20 watts >> less, if the final tubes are reasonably good. You should be able to >> load up to about the same plate current on both bands. >> Other than that possible problem, the TR-3 can be a good rig for >> SSB >> operation, usually at a good price, also. S-meter often seems stingy, >> just turn up the AF gain if needed, signals are there. Definitely check >> out the p.s. and replace the bias filter cap at least. >> 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 >> >> On 12/11/2012 12:09 AM, lane denune wrote: >> > Hi Guys ; Considering a fully functional TR-3 from the owner of 15yrs. >> > I've been invited to try it on the air at his shack before I take it. >> > Being a relative newbie to Drake equipment, is there any particular >> > areas to consider with the TR3 other than the obvious and general >> > operating condition? >> > I don't recall anything negative in particular about this vintage >> > radio. I will upgrade the power supply and finals..Anything come to >> mind? >> > Thanks 73 de n8aft. >> > >> > >> > >> > ___ >> > Drakelist mailing list >> > Drakelist@zerobeat.net >> > http://mailman.zerobeat.net/mailman/listinfo/drakelist >> > >> >> >> >> -- >> >> Message: 2 >> Date: Tue, 11 Dec 2012 15:12:38 -0500 >> From: Lee Hiers >> To: drakelist@zerobeat.net >> Subject: Re: [Drakelist] TR-3 >> Message-ID: >> > 7nzbfs+eqfb4pgsgngmzow8jodkwph5dhyxcvfk8hx...@mail.gmail.com> >> Content-Type: text/plain; charset="iso-8859-1" >> >> On Tue, Dec 11, 2012 at 12:00 PM, >> >> > wrote: >> >> Being a relative newbie to Drake equipment, is there any particular areas >> > to consider with the TR3 other than the obvious and general operating >> > condition? >> > ?I don't recall anything negative in particular about this vintage &
Re: [Drakelist] TR-3
Hear, Hear!. I agree with John. What we do with these old radios vary with the number owned and sold: endless. But for me, I enjoy the simplicity and the warmth that using a piece of history gives me. Have a few radios, the old tube ones are the favorite. I say go for it and fix it and clean it and learn to love it. On Tue, Dec 11, 2012 at 5:43 PM, John King wrote: > Should you buy a TR3? I think the answer should be given after determining > what he plans to do with it. One reason to purchase a Drake TR3 is the > historic value to the hobby.I have been licensed for almost 54 years and > have grown with the hobby from 6AG7/807 tube transmitter and Hallicrafters > S40A receiver. They were wonderful for the purpose for which they were > built and intended to been used. They are not my gear that I use regularly, > but they bring back wonderful memories. I have one hundred of more radios > from 1940 until present. I am NOT A COLLECTOR but I accumulate tube type > radios of all manufacturers because of what they were and what they still > are. Swan was pioneer in the transceiver field and did a great job from the > SW 175 and continued for many years, even after being bought out by Cubic > Communications. > > The TR3 is historic because it was R.L. Drake's FIRST transceiver. I HAVE > A TR3 THAT I BOUGHT REASONABLY OFF EBAY IN NON WORKING CONDITION AND VERY > DIRTY. Today it is a nice looking and working radio. Do I use it > everydayNO!! WHY? I have the first model receiver that Drake built, the > Drake 1A serial number 518 of 1000 built. When built, it was arguably the > best receiver made in its' day( I also own a Collins 75A1, 75A2, and 75A4, > for comparison). l am not bragging, just pointing out my perspective. I own > a Drake 2A. Drake 2B, TR4 (that I use almost daily for net operation, R4, > T4X,R4B,R4C,and T4XC and a great Drake L4B amp. No, they are not the > $10,000.00+, Icom or the latest Kenwood, Orion or other solid state rig. > > The TR3 basically popularized the use of transceivers. There are many hams > today who may not be able to operate separates. Other companies had gotten > into the transceiver production, but not as affordable and basic as the TR3. > > My suggestion is that if you expect an almost "owner inability" rig to > repair, digital readout with 3,000 memories, 65 push buttons, DON'T BUY the > TR3, BUT "SOME DAY' you might wish you could find one to buy. > > This is not intended to start a THREAD, it is just my opinion. If anyone > wants to attack my opinion, don't bother the reflector with it, feel free > to reply DIRECTLY to me. 73, John, K5PGW > > > > > *To:* drakelist@zerobeat.net > *Sent:* Tuesday, December 11, 2012 12:12 PM > *Subject:* Re: [Drakelist] TR-3 > > On Tue, Dec 11, 2012 at 12:00 PM, > > > wrote: > > Being a relative newbie to Drake equipment, is there any particular areas > to consider with the TR3 other than the obvious and general operating > condition? > ?I don't recall anything negative in particular about this vintage radio. > > > For one, it's a terrible CW radio...if that matters to you. > > 73 de Lee > -- > Lee Hiers, AA4GA > www.aa4ga.com > > Submit your totals to the unofficial QRP DXCC standings - go to * > http://www.aa4ga.com/p/qrp-dxcc.html* for more info! > > > > ___ > 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 > > -- David Assaf, III W5XU ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T4XB squealing audio
Got the rx on ext mute in a twin config? Sent from my iPhone David Assaf, III On Sep 10, 2012, at 3:44, "Peter Ravn" wrote: > After alignment per manual of the RF and mixer stages, my T4XB has got a > squealing transmit audio which in my R4B sounds like RF feedback. The problem > is on all bands and on both sidebands. > > I did nothing but adjusting the four trimmers for each band to maximum. > Afterwards I have checked cables, the mike plug, the mike (Turner +3B) and V9 > in the mike amplifier. The problem is still there. > > Thanks > > Peter OZ8CTH > > ___ > 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] Test
Me too! Sent from my iPhone David Assaf, III On Mar 8, 2012, at 9:57, "Donley" wrote: > I lost my connection to the Drakelist and am testing to see if it has been > restored. > > Richard > > > ___ > 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] Sherwood crystals
No Sent from my iPhone David Assaf, III On Jun 7, 2011, at 7:23 PM, Neil M Califano wrote: > Does Sherwood manufacture their own crystals? > > ___ > 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] Inproved audio amp for R-4C
Sherwood. It is in an r4c modified many years ago. Sent from my iPhone David Assaf, III On Jun 5, 2011, at 9:48 PM, "Jim Shorney" wrote: >> > ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake T4-X Frequency "Wobble"
While the mechanical issues are certainly a possibility you might want to try An experiment. If the radio cuts up when it is cold it may be the Zener diode in the vfo. If this is bad even cold the radio will jump frequency. Try the mechanical Fixes including the grounding strap. If that does not work suggest replace the Zener Good luck Sent from my iPhone David Assaf, III On Oct 26, 2010, at 6:46 AM, Curt Nixon wrote: Hi Eddy: That brass end sticking out the back of the VFO can is the shaft that the permeability cores are mounted on. You can carefully remove the can from the back by squeezing the spring latches on the front of the can. The back end of the shaft simply rides along on the phenolic end of the coil form. Generally, this is smooth but if you move it by hand, the frequency changes..its pretty sensitive. It is possible that there is some dirt or gunk there that might make it move slightly with temp changes and you might carefully brush the shaft and giude with an artists brush and some isopropyl 99% alcohol. If the cover is off, you can also inspect to insure that the glue that holds the end pc in place, is not loose. Also the glue on the coils. A bit of nitrocellulose glue...airplane cement, can be use there and be exactly equal to original. I use "Ambroid" brand..amber wood model glue. It is generally behind the counter at hobby stores. Also, the grounding of the traveller bar that runs in and out on the screww shaft can become intermittant with dirt and lubricant. A common modification is to use a strip of desoldering braid to make a flexible grounding strap between the frame and the moving slider that runs on the vfo screw. I'll see if I can find some pictures of all this if you need them. Be very delicate on removal of the cover. Anything in there that gets damaged or moved will be a problem. But it isn't rocket science either. I think the simplicity of the design is why they keep running so well 40+ years after manufacture. Cheers, Curt KU8L Edward Swynar wrote: */Hi Guys,/* At Garey's suggestion, I've started to monitor the on-the-air CW signal of my T4-X directly on my R-4 receiver---I also just recently "retired" my electronic keyer, in favour of my /Vibroplex/ Presentation bug... Now, I don't know if it's due somehow to all my rockin' & rollin' with the bug next to the T-4X, or what, but all of a sudden I've noticed that periodically, and for no apparent reason, the / quality/ of the monitored frequency of the T-4X will get "/jumpy/", or /shift/ ever-so-slightly, during transmit...in worst cases, it will actually sound garbelled & "/wobbly/", almost like that of a participant in the annual /AWA 1929 QSO Party!/ I've rotated all of the switches on the transmitter, removed the tubes & replaced them, cleaned the switches, cleaned the tube pins, with no noticeable & direct cause-and-effect. Last night, in desperation, I tried my tried-and-true "/pencil tap/" trick when trouble-shooting intermittents like this: with the top cover removed, I tapped every tube, compartment, & protrudance atop the T4-X chassis with the eraser end of a pencil, hoping to generate the symptoms of the intermittent... I came up blank, /UNTIL/ the pencil tapped the VFO shielded enclosure: I could emulate/generate the /very same symptoms/ as before, just by gently rapping the VFO "can". I next placed my finger on the yellow-coloured device that ever-so-slightly protrudes out the rear hole in the enclosure, and by applying the lightest of pressure, I could change the frequency of the transmit signal by the same margins as when the condition first reared its ugly head. This hardly seems conducive to operation under trying conditions, I said to myself! It dawned upon me that maybe if this yellow-coloured device might somehow be physically "stabilized", the issue might disappear. I'm thinking of a simple strip of masking tape applied over the hole of the VFO enclosure, contacting both it and the protruding "device". I'd like to examine the VFO in my R-4, first, however (it has no such instability issues whatsoever). Has anyone ever encountered such a condition before...? And just what exactly is /inside/ that VFO shielded enclosure, anyway...? Do I dare to remove it, or will my doing so unleash a whole new / Pandora's Box/ of woes & misfortunes upon yours truly...?! Many thanks in advance for any & all insight in this regard... */~73!~ de Eddy VE3CUI - VE3XZ/* *//* --- - ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailma
Re: [Drakelist] 6JB6 Question
Please also remember thses tubes were designed for the horizontal output on TV s. This is a constant and severe service. With loading care they will last a very long time. I have a set in some 1964 t4xb units that are original and still function well on 10 meters. The advice about using tubes of the same manufacturer is sound as once the setup was perfected the tubes we very close to each other. Good luck. Sent from my iPhone David Assaf, III On Sep 27, 2010, at 10:23 PM, Garey Barrell wrote: The 'real' catch is that these tubes were originally designed to work at ~16 kHz, NOT 30 MHz. So depending upon internal structure, a tube that works at 15 kHz may not work at all at 30 MHz. The inter-element capacitances are balanced out by the neutralization circuit, and these may differ considerably depending upon who made the tube. These capacitances have little or no effect at 15 kHz, but ... A plain emission tester will tell you if the tube is 'dead' at DC, but all that means is that there is still some coating on the cathode and that none of the major elements are shorted. I don't know enough about tube science to explain WHY, but in this service these tubes lose gain at the highest frequencies first, and progress downwards. A tube can produce 85W on 80M and 0W on 10M. But they weaken from the 'top down'. The best thing you can do to prolong tube life is to put a small fan either on top of, or on the back of, the PA cage, blowing UP or OUT. It doesn't have to move much air to make a major difference in reducing the heat in the cage. A small computer fan that runs silently is fine. Good PA tubes will run for literally years as long as you don't take 10 minutes to tune them up because you have the wrong antenna selected. I was able to get over two years in full power RTTY service back in the 60's. Typical SSB or CW should last 5 - 10 years. The PA tubes in my 'daily driver' T-4XB are over 10 years old. Drake matched final tubes by selecting according to cathode current vs bias voltage at idle. They can be matched in the transmitter by installing ONE tube, and setting the Bias voltage for 35 mA of cathode current. Then replace that tube with successive tubes, without adjusting Bias, and note the current drawn by each tube. Pairs are two tubes that are closest to each other in current drawn. If most of the tubes tried draw 40 mA in this situation, install one of those, reset bias to 35 mA and try again. Obviously the meter in the T-4X(any) isn't all that accurate, (it DID cost around a dollar new!,) so it's best to measure the voltage drop across the 15 ohm resistor for the socket being used. Measure the actual resistance and then measure the voltage across it for 35 mA. From a practical standpoint, two new tubes from the same manufacturer are probably close enough. A reasonable target is to find a pair that are within 5% of each other at idle current. Matching IS important, because these tubes are being run VERY hard. IF one tube is only carrying 90% of the load, the other is doing the 110%, adding insult to injury. And third-order distortion products go up rapidly! Best brands seem to be Sylvania, Zenith, RCA and GE, in that order. Other brands may or may not neutralize properly, depending upon who actually built them. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-B, C-Line& TR-4/C Service Supplement CDs Curt wrote: Experience with finals on my T-4XB prompts some questions. Can a simple emissions tester be used in any way to estimate 6JB6 performance in circuit? Can that tester be used to "match" 6JB6 tubes? Evidently these transmitters were pretty picky about what PA tubes they would tolerate, with differences between manufacturers being an issue. Another thing I'm wondering is whether most of the 6JB6 tubes for sale these days are used and maybe already worn out. One pair I bought off the web were pretty useless in my T-4X. Any source of known-good 6JB6s? Changing out the finals and then neutralizing them is a pain in the rear I'd like to do rarely, would like to somehow know that the replacements are better than the soft tubes being replaced. 73, Curt KB5JO ___ 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] unstable R4C PTO
If you are not turning the dial and it jumps then it is not likely a mechanical issue. As stated before the vfo oscillator is quite voltage sensitive. My bet is the Zener as I have written earlier. Solid state devices were not consistently uniform as they are now and with use can get into an unstable part of the curve and exhibit an inconsistent impeadence and hen e the jump. Suggest you change the Zener Sent from my iPhone David Assaf, III On Aug 24, 2010, at 10:22 AM, "steve white" wrote: Dennis I had this problem once in a old HQ170 and it turned out to be the C in the vfo LC circuit. It was a nice looking mica capacitor and I didn’t think at first that it could be the problem but after all the other things I changed once I replaced it all was right with the wo rld again. Steve NU0P From: drakelist-boun...@zerobeat.net [mailto:drakelist- boun...@zerobeat.net] On Behalf Of Dennis Monticelli Sent: Monday, August 23, 2010 23:59 To: pony...@aol.com Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] unstable R4C PTO Zener diodes can develop an instability in their voltage "knee" value due to migration of mobile charge at the surface of the semiconductor. A random walk of a few tens or hundreds of mV could produce your frequency problem. Put a scope probe on the zener and set your scrope for high sensitivity. See if you observe a "jumpy" voltage. Dennis AE6C On Mon, Aug 23, 2010 at 6:37 PM, wrote: Hi Gang, Thanks for all the replies to my past message, but at this point in time, I'm even more dumbfounded than ever. So far I have cleaned, and oiled the mechanical parts, installed a ground strap on the PTO, resoldered all the ground wires inside. everything is free, and working as it should. Also, I drilled another hole in the cover to stretch that angled spring giving more tension. No avail, now I think it must be an electronic problem, as sometimes, when I try to tune a station, it warbles, sometimes while I am just listening hands off. vibration doesn't seem to change anything. Someone emailed me suggesting the zenner diode could be the culprit. I always thought most solid state devices either work, or don't work. Is it possible that's the problem, or could it be somewhere else outside the PTO? Thanks for reading thisTom, WD8JPP ___ 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] R4C unstable VFO
Sorry. Zener diode in the vfo Sent from my iPhone David Assaf, III On Aug 20, 2010, at 12:28 PM, David Assaf wrote: Change the 3zener diade in the CFO Sent from my iPhone David Assaf, III On Aug 19, 2010, at 4:19 PM, pony...@aol.com wrote: Hi People, I've got an R4C that is jumping frequency by +- 1 Khz, then slowly returns to the correct frequency only to repeat again, and again. I have installed the ground strap mod, and exchanged several tubes, cleaned the switching, and checked all the RCA jacks on the rear panel. At this time I don't know where else to go. Has anyone had/ corrected this problem? Any help, or suggestions would be greatly appreciated. Tom ___ 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] R4C unstable VFO
Change the 3zener diade in the CFO Sent from my iPhone David Assaf, III On Aug 19, 2010, at 4:19 PM, pony...@aol.com wrote: Hi People, I've got an R4C that is jumping frequency by +- 1 Khz, then slowly returns to the correct frequency only to repeat again, and again. I have installed the ground strap mod, and exchanged several tubes, cleaned the switching, and checked all the RCA jacks on the rear panel. At this time I don't know where else to go. Has anyone had/ corrected this problem? Any help, or suggestions would be greatly appreciated. Tom ___ 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] R4C static after Sherwood 3d mixer mod
Same thing on the filter selector switch. Not using the radio will usually have a switch issue. A bit od deoxit will resolve thAt issue. Good luck. The third mixer did adequately address the third mixer prob. Drake had 3 or 4 designs and Sherwood. Solved it all. A clean and functioning Sherwood receiver is a wonder. Still use mine Sent from my iPhone David Assaf, III On Jul 31, 2010, at 9:48 AM, Robert Ladden wrote: I had this problem when a crystal filter on the back was not making a good connection with one of the pins. Wiggle each filter. The static crashes would occur out of nowhere and last a few seconds. Took me weeks to find it. 73, Bob WW3QB --- On Sat, 7/31/10, K4GM- George wrote: From: K4GM- George Subject: [Drakelist] R4C static after Sherwood 3d mixer mod To: drakelist@zerobeat.net Date: Saturday, July 31, 2010, 8:06 AM I have obtained an R4C with many of the Sherwood mods installed including the solid state 3d mixer which is supposed to eliminate the dreaded frying crackle. Unfortunately occasionally I hear a bit of static sounding to me like what a brief solar flare might sound. It is not really a hiss but more like a strong static crash. It is definitely not simply QRN! It is infrequent and I can still copy over it. Before I open it up and start reviewing the wiring on the mixer mod, has anyone else had experience with this type of problem? Is there a known culprit such as one of the tubes going bad?? Any and all suggestions appreciated. George K4GM ___ 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] Line C - Frequency counter problem
You might consider the cables connecting the counter. Smaller cables add lots of capacitance ans as such adds load. I have used the torrestronics unit and another on both the b and c line twins with no issues using 58 size coax. Good luck. The read out is certainly a great addition Sent from my iPhone David Assaf, III On May 10, 2010, at 3:32 PM, Curt Nixon wrote: Yes...I wasn't very clear on the amp at the Rx approac. It would still be on the counter leg of the Y. really an "L"...so the INJ path is still same as original between R and T but the extra cable capacity going to the counter is reduced by the 12 to 16 inches of cable I have now up to the RO box on the top of the Rx. Its one of those things on my to-do list: characterize the whole system to try to find a definitive problem and solution...but so many other things to do !!;) Yes the sensitivity of the RO is not that great as I recall the signal just goes to an input pin of an 74HC4046 then to the PIC. Another thing I wanted to try on the barefoot counter was to reduce the input blocking caps from .1MFd down to a few pico's. the input is a series .1, a series 100 Ohm , then another .1M in series.. then the parallel clipping diodes to ground right after the Res. Seems like the input capacity can be reduced a lot by making the blocking caps smaller. Couldn't be a lot worse I think. Garey Barrell wrote: Sometimes it works, but mostly not, lately. I used to just reply to the list, but now I reply to all so at least the person I'm addressing the reply to gets it. Actually they get it twice if the list happens to work! :-) You can't put the amp at the junction of the "Y" because of the DC control voltage. Unless your FET amp passes DC both ways through it! The problem is most likely the sensitivity of the counter dropping off with higher frequency, plus the effect of the cable parallel capacitive loading. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs ___ 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] VOX Relay Cable connector for AC-4
In the old days of tv sets that had removeable backs supply houses would sell a cheater cord that would go between the back that is removed and the set itself. This extension was an exact fit for the receptacle on the power supply.you can also bring out the two wires thru the chassis ans go from there. Note that some early ac 3 units did not have this connector. Good lick Sent from my iPhone David Assaf, III On Jan 22, 2010, at 12:15 PM, Paul Gerhardt wrote: Anybody have a part #/source for a VOX connector for the AC-4? What else can you use to make a relay cable? Going to try the 'B' line on one of my amps. Some Drake restore pix on blogspot -- Paul Gerhardt K3PG http://pgerhardt.blogspot.com QRP ARCI 6674 FP 274 ___ 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-4XB strange ma value
Bias. Could always effect plate current. What it sounds like is tuning to some harmonic that will find a strNge resonance and draw current. As this is likely A frequency outside the bands and likely harmfucl it is good to reduce the gain quickly. The book has some good guidelines on the rough position of the controls that will prevent this In my experience a power supply capacitor is not generally an intermittent issue, it is either bad or good. If wou have a lot of miles on the power supply it would be good insurrance to clean it up anyway. Good luck. Sent from my iPhone David Assaf, III On Jan 25, 2010, at 9:22 AM, Garey Barrell wrote: Frank - Interesting! One thing, tuning the RF TUNE to the "middle of the 80M band" _segment_ is probably tuning to the IF of 5.645 MHz. I certainly suspect Bias supply troubles. Is the FInal idle setting ok at 70 mA? Possibly intermittent loss of Bias which could partially "key" the transmitter. I would strongly suggest replacing the Bias supply filter caps at a minimum. The chances of catastrophic failure with considerable damage are just too great to ignore. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs iz oos wrote: Hi Folks, Premise: my AC-4 has still all the original caps, included the bias ones which I should decide to change. Weeks ago, I had experienced something very strange with my T-4XB. It tunes correctly, but, at a particular point of the RF-TUNE in the middle of the 80 meters band, it absorbed 320mA notwithstanding the rig was going to be tuned on completely others band such as the 20meters band with the GAIN control set to minimum!!! This scared me. It happened twice, albeit I was very quick to move the RF tune knob so I saw the 320mA just for less than a second or so. It seems that no apparent damage occurred, as I tuned the rig on the band correctly. But after that day then I haven't turned the rig on again. Could it be due to the bias caps or to something else? 73, Frank IZ2OOOS ___ 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
