[Drakelist] R-4C IC Product Detector
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] SPR-4 Crystals Needed
Hello- I am searching for SPR-4 crystals. There are a number of ranges I need. Anyone with a stock of these? Thanks, Byron.___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Needed: S-Meter for Drake 2-A
Hello- I am in need of an S-Meter to for a Drake 2-A receiver. Will consider a parts unit to get a meter. Thanks all, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] 100 KC Calib.
Hello- I am going through an R-4 receiver and the 100 KC calib output is weak. The receiver sensitivity is very good. The calibrator will only push the S-meter up to 5 dB over S-9 on 80 meters, and it barely moves the meter pointer on 10 meters (S-meter at max sensitivity setting). Some of the stronger 75 meter signals are giving 40 over S-9 on this R-4. Another R-4 here moves the S-meter to around S-5 on 10 meters. I have checked voltages on the 12BA6 calib tube and all are close, except the pin #1 (grid) voltage measures -37 v. The manual says it should be around -28 V. The 1 meg grid leak measures 1.05 meg, I didn't change it out. Would the higher neg voltage on grid decrease the output? If so, should I lower the value of the grid leak? I thought I would ask before I go to trying to compare the outputs of the R-4 calibrators, or tear into the other R-4 to measure voltages, etc. Thanks, Byron WA5THJ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] SPR-4 Crystals
Hello- Does anyone on the list know where I can buy ham band crystals for the SPR-4? There used to be a lot of them on eBay but I don't see them anymore (now that I need to find some!). Also, does anyone have a TA-4 trtabsceive adapter? Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] For Sale: Very Nice R-4C
Hello All- I have for sale a very nice Drake R-4C receiver. It is in excellent condition and is in one of the replacement boxes, with styrofoam pillars, that is the same size as original box. These boxes were common when units were sent in for repair. Here is the rundown on the R-4C: Has 3 extra filters, all Drake filters, mounted on rear panel. No AM filter internally, however. Has crystal calibrator. Has cover plate for spare crystals, however no spare crystals. Has original manual. Is all original with no modifications. Serial number is 25,5XX. Works very well, beautiful shape no issues. I am asking 450.00 plus shipping. I would do a partial trade for an excellent condition R-4, R-4A, R-4B, or SW-4. An even trade for an SPR-4, depending on accessories. Thanks All, Byron WA5THJ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-3 SSB filter question
Hello About TR-3 Filters: I have replaced the soup can filter in several TR-3's with this method, however it is fairly major surgery for the ol' gal. 1. Removed the soup can and dis-assemble it, preparing the switch (only) for the new filters. 2. Obtain a pair of the 9.000 filters (USB / LSB) from a Harris RF-350 or similiar military set. These are small, good filters. 3. Mount the two filters, one above the other, on a piece of Radio Shack proto board, suspended by stiff wire for grounding, and wired to switch. 4. Change resitors at both filter match transformers to 510 ohm 5. The center pin of filter match IF's is not used anymore. From: Al Parker anc...@ec.rr.com To: Mark Pilant pil...@sambelkee.mv.com Cc: drakelist drakelist@zerobeat.net Sent: Sat, January 22, 2011 12:45:07 PM Subject: Re: [Drakelist] TR-3 SSB filter question Hi Mark, I had the same thought 8-10 yrs ago, collect TR-3's and have some good ones. I gave it up ;-( and sold all I had to one guy. The filter response, in my experience, isn't as much of a problem as just one having developed much more loss than the other. The carrier xtal also does drift off a bit sometimes you can end up with it outside one of filter, and far from the other. I had the idea of doing like others (e.g Swan) did, just use the one good filter and switch the carrier osc. from one side to the other. Shouldn't be too hard, using a small relay. 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 1/22/2011 1:12 PM, Mark Pilant wrote: Hi Garey. No, no sentimental value here... just looking to get the rig fixed up to where it should be. I suppose I could always start collecting TR-3s and get one (or more) good examples :-) :-) I actually suspect the issue I'm having is one of alignment. Last time, I went strictly by the manual, and the rig performed OK. This time, I think I'll put some of the test equipment I have to use. I may even take the time to sweep the filters to see just what the response curve looks like. Oh boy... another project :-) :-) 73 - Mark N1VQW ___ 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] Drake 2B Parts Needed
Hello- Anyone with a Drake 2B parts unit? I need the bandswitch wafer that switches the crystals. Could also use a few other various parts, would buy an entire parts unit if necessary or available. Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Speaker For 2BQ
Hello- I believe the originasl speaker for the Drake 2-BQ was a Jensen Concert if I recall correctly. I need to find a suitable replacement for a 2-BQ I am restoring, it has a real cheapy looking speaker in it now. Any recommendations? Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Fire... really
Possibly a cathode resistor for one final? ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Wanted: TA-4 for SPR-4
Hello- I am in need of the TA-4 transceive adapter board for my SPR-4, does anyone have one for sale? Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Needed-SPR-4 dial window
Hello- My SPR-4 dial window (plastic with red vertical line) has yellowed, does anyone sell these, or have parts units to rob one? Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Drake 4-Line interconnecting cables
Hello- Recently I was looking for a source of low capacitance cable to make up a few Injection cables to couple the Drake twins together. I believe I was informed of the original spec on this injection cable was 60 pF. total capacity, 39 tip-to-tip, and Drake used a Belden microphone coaxial cable to make them. I have been searching to no avail for the smaller cable, I do not want to use the larger cables such as RG-62 if I can avoid it. Another thing kind of threw me off track: I found a set of interconnects that were supplied with a T-4XC, from Ed Mooray up in Ark. years back. They look like the original Drake to me, and they have the marker tags on them. The injection cable has a metal tag with INJ stamped on it on each end of it. Physically the cable looked the same to me, with the molded connectors, etc. I used my trusty AADE capacitance meter and the cable measured a whopping 97 pF! So, has anyone checked their original Drake cables to verify? Anyone know of a source for smaller, low capacity cable? Thanks, Byron.___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] R-4A 12BE6 Voltage
Hello- I hit a snag in checking out a Drake R-4A, one of the 13 tube versions. It works but is not quite right in my opinion. After doing resistance checks, and not seeing anything way off, I thought I would check voltages next. For V-3, the 12BE6 converter, in the manual for pin #1 it shows -11.5 VDC as the normal voltage reading. I show a little less than -0.05 VDC. Pin #1 of this tube has the 5645 Khz. crystal and capacitive divider connected to it. The converter tube is working, would the lack of negative bias being developed be a function of the crystal activity? I tried several good 12BE6 tubes with same results. The rest of the volttages on this tube check reasonably close to what the manual says. I thought I would ask if this is something I should pursue further, or not worry about it since the converter is working, however the receiver is low on gain. Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-3 Crystal Filter(s)
Regarding the TR-3 Crystal Filters: I have used and compared the soup can and the little dual - unit filter sealed filter in TR-3's. I believe the little dual-unit filter is noticeably better. I sent in a description to the Drake reflector about a year back or so on how to replace the TR-3 filters with a pair of the Harris 9 Mhz filters. I had been getting the Harris filter pairs from several fellows who were pulling them out of the RF-230's I believe. These filters are small but very good, supposed to be 8 pole units. Years ago ( back in early 90's) I bought some 9 Mhz filter pairs from an ad in Electric Radio. They were sealed in plastic bags in USB, LSB pairs. There was a spec sheet for each filter. When I looked closer at these they are in fact the same filters as used in Harris units. Take Care, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-4 Noise Blanker question
Hello- I have been following this thread on duplicating the Drake TR-4 noise blanker closely. Actually, I have been thinking of trying to do so myself for some time, and have been communicating with certain folks regarding such. I was hoping to find a scrap noise blanker to strip the components from, namely to unwind the torroids (to get winding info) and then to measure permeability of the cores. As far I know there is no difference between the different versions of the noise blanker for TR-4 series, regarding the PC board itself. I have compared a later 34-PNB PC board with an early 9-NB PC board and the circuit is the same. There is some confusion regarding the little PC board that was supplied with some early 9-NB noise blanker kits. I believe the confusion stems from the different impedances of the IF filters and their matching transformers. Some early TR-4's had the soup can IF filter, wheras later ones went to the nice 8 pole units. The soup can has around 2200 ohms resistors across matching transformer winding versus about 470 ohms for the 8 pole units. The little PC board was for matching into these, but is really not needed as was later proven out. I have seen all the various noise blanker installs, from the early 9-NB one using the added switch concentric with the PA Tuning control, to wired in TR-4's with front panel switch to the plug-in 34-PNB. I have removed the noise blanker (from parts unit TR-4's I bought) from several early-type installs with the little matching-PC board, then re-installed these in TR-4's but minus the little PC board. I installed one of these blankers in my TR-3 with good success. I would like to participate in an effort to duplicate the noise blanker PC board. The PC board is the main problem to me, as I don't believe there is any artwork surviving out there. It appears we would need the help of someone who could produce the artwork, using an existing board as a guide. As far as getting the parts and construction I believe that could be done OK. So here is my two cents on the thing. Thanks, Byron WA5THJ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] FS or Trade TV7-D/U
Hello- I have a TV7-D/U tube tester that I would like to trade towards a nice condition Drake R4-A / T4-X Line. The TV7-D/U is in good condition and all accessories and original book are in lid. It works well. Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] WTB: Nice T-4X
Hello- I found a very nice R-4 receiver and now I would like to find a mate for it. Anyone have a very clean T-4X for sale? Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] SPR-4 Semiconductor Info
Hello- Can anyone tell me what the generic part number is for these Drake-branded devices found in the SPR-4? Q-9, Q-12, Q-13 = EP487 (TO-220 power transistor) CR-8, CR-22 = AN994 (Zener Diodes) Thanks! Byron WA5THJ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Wanted: TA-4 for SPR-4
Hello- Does anyone have a model TA-4 transceive adapter for the SPR-4 receiver that is for sale? I would like to mate an SPR-4 with a T-4XC transmitter. Thanks, Byron WA5THJ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] SW-4A Query
Hello- I have never been able to play with and examine a Drake SW-4A until recently. I am glad I was able to add one to my Drake line-up here. I was curious if anyone knew the percentages of the selectivity of this receiver as determined at the 5645 KC crystal filter or in the 455 KC IF? I was looking at the JW Miller 455 KC IF transformers used in the set. I have some in the same Miller line that are a little more selective. I realize that there would probably be a slight gain reduction with them. The receiver does seem a little broad even for an AM set. Another thing is the ACC socket. What accessory was used at this socket? Thanks, Byron WA5THJ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] neutralization method using simple method, requires a receiver
Hello- I neutralize my Drake's by: 1. Disconnect screen voltage to finals. 2. Tune up transmitter PA as normal on 10 meters into a dummy load, although there is no discernable output on wattmeter. Listen to the signal on a receiver. Tune up transmitter for max signal in receiver. Adjust receiver gain to prevent overloading. 3. Adjust neutralizing trimmer for minimum signal as indicated on receiver S-Meter. 4. Reconnect screen voltage to finals. Hope this is of use, Byron WA5THJ. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [drakelist] TR-4 TX Hang-Up
Thanks Carl- I will remember this. I do have a couple of those boards here in reserve. Thanks, Byron. - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, April 29, 2008 3:23 PM Subject: Re: [drakelist] TR-4 TX Hang-Up [EMAIL PROTECTED] writes: Byron WA5THJ. My TR4 with the original (fixed) relay would not pull in originally. After cleaning the relay points it wouldn't release as you describe. After putting the VOX VOX delay pots mid range and on the third cleaning it did work ...sometimes. If The VOX pot has a wrong setting was the big culprit. All of the above info on line and Drake relative. Wound up installing a John Kriner (OEM) relay board and of course a new plug in relay. All fixed. Carl Hibbard WD8NHK -- Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.
Re: [drakelist] TR-4 TX Hang-Up
Byron Tatum [EMAIL PROTECTED] made an utterance to the drakelist gang -- Thank You Garey for the excellent help and service! - Original Message - From: Garey Barrell [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, April 29, 2008 3:19 PM Subject: Re: [drakelist] TR-4 TX Hang-Up Garey Barrell [EMAIL PROTECTED] made an utterance to the drakelist gang -- Byron - OK. Relays take more coil current to pull in than they do to hold in. It takes a certain amount of current through the coil (pull) to drag the armature from it's non-energized position to the energized position. It takes much less current to (hold) it once there, so slight leakage might NOT be sufficient to pull, but more than enough to hold. I don't know of any good way to touch up the panels. The original paint is so thin, (I actually think it is more a dye (anodize?) than paint, but don't know for sure,) and as a result any sort of paint ends up looking worse than the mark! For a small mark or two, it might be possible to just fill the mark to the level of the panel, but a string of numbers would be a real challenge. Never could understand people that do that sort of thing, especially on the front panel!! I just saw your order. There are scans of both the 34-NB and the 34-PNB manuals, with quite a bit of information, plus I have added a photograph of the board itself with active components and alignment info annotated. There is also a Voltage table for the NB, which has not been previously published. It's really a straightforward design, and most units in the field benefit from an alignment. A lot of the components are common between the TR-3 and TR-4, but every once in a while they threw in a curve like that cap to keep us off balance! :-) Your CDs will go out tomorrow. Thank you! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com Byron Tatum wrote: Byron Tatum [EMAIL PROTECTED] made an utterance to the drakelist gang -- Hey Garey- Thank you for the comments and help. I start nights at work and will have several to complete, then I will get back into the TR-4. I will measure voltage as you suggest, looking for a slight voltage drop. Then I will check out relay itself. I am beginning to think that it is the magnetizing of pole piece and relay wear that is the problem. If it was a leakage to ground on the 6EV7 pin #1 lead you might think the set would go into TX on its own (relay energize) every now and then, of which I have never saw it do. One other thing- I bought a nice TR-4 from a fellow, based on several pictures, but the photo angles, due to glare, covered up (of all things) a ham's DL # engraved on the front panel in tiny lettering , immediately to the right of TR-4 on front panel. Do you know of a touch up paint that matches the darker grey of that front panel area? I got the set for a decent price, it was nice and had the built in NB, but had a problem (as advertised). I found T-9 to be burned out in center area of coil form. I had a spare T-9 from a parts unit TR-3. Thank goodness I opened up the TR-3 T-9 transformer before I installed it -- it had a 56 pF cap in it that was not in the TR-4 T-9. Otherwise the coils looked the same. Anyway, I clipped out the capacitor and all went OK after the repair. That is not a fun repair for sure!! CUL, Byron. - Original Message - From: Garey Barrell [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, April 29, 2008 1:46 PM Subject: Re: [drakelist] TR-4 TX Hang-Up Byron - Well things were going well until you pulled the tube out of the socket! :-) There are a limited number of possibilities in that case. The relay coil leads go through the feedthrough bypass caps _under_ the power connector. Of course the relay lead to the 6EV7 is the one UNDER the Jones connector, the last one in the arc of feedthroughs there. (C92) There are no more components between this feedthrough and the 6EV7 tube socket. The other relay coil lead goes directly the +250V bus via the next feedthrough cap along the arc, (C91). So the voltage measured at the tube socket pin with the tube out should be exactly the same as the +250V bus. Any drop would indicate leakage. See attached photo from my CD (at reduced resolution). So. Leaky C92, leaky tube socket, pinched wire. One possibility I have seen a few times is the down stop on the relay gets hammered down over the years, allowing the armature to actually touch the pole piece of the coil. The pole piece is slightly magnetized, and if the armature physically is in contact with it, it will stick. An easy check is to slip a piece of paper in to prevent metal to metal contact between the two. The down
Re: [drakelist] TR-4 TX Hang-Up
Ron- Your suggestion sounds very credible due to the fact that my problem worsens as I cycle the relay more (add more heat in coil) plus creating heat in PA area. Thank you!! Byron. - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; [EMAIL PROTECTED] Cc: Garey Barrell Sent: Tuesday, April 29, 2008 3:49 PM Subject: Re: [drakelist] TR-4 TX Hang-Up I saw once where the relay iron core was expanding do to the heat the coil generated around it, which to this point is normal. But in this case as the core expanded it shorted against a bare coil winding. The core itself being at ground potential, when shorted against the coil winding provided the ground path to key the relay.Once the relay was unkeyed by removing power, it cooled, and worked again as normal until it heated up again. So don't put aside the possibility of a heat related problem in the relay itself. Ron / WB4HFN -- Original message -- From: Garey Barrell [EMAIL PROTECTED] Garey Barrell made an utterance to the drakelist gang -- Byron - OK. Relays take more coil current to pull in than they do to hold in. It takes a certain amount of current through the coil (pull) to drag the armature from it's non-energized position to the energized position. It takes much less current to (hold) it once there, so slight leakage might NOT be sufficient to pull, but more than enough to hold. I don't know of any good way to touch up the panels. The original paint is so thin, (I actually think it is more a dye (anodize?) than paint, but don't know for sure,) and as a result any sort of paint ends up looking worse than the mark! For a small mark or two, it might be possible to just fill the mark to the level of the panel, but a string of numbers would be a real challenge. Never could understand people that do that sort of thing, especially on the front panel!! I just saw your order. There are scans of both the 34-NB and the 34-PNB manuals, with quite a bit of information, plus I have added a photograph of the board itself with active components and alignment info annotated. There is also a Voltage table for the NB, which has not been previously published. It's really a straightforward design, and most units in the field benefit from an alignment. A lot of the components are common between the TR-3 and TR-4, but every once in a while they threw in a curve like that cap to keep us off balance! :-) BR Your CDs will go out tomorrow. Thank you! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs Byron Tatum wrote: Byron Tatum made an utterance to the drakelist gang -- Hey Garey- Thank you for the comments and help. I start nights at work and will have several to complete, then I will get back into the TR-4. I will measure voltage as you suggest, looking for a slight voltage drop. Then I will check out relay itself. I am beginning to think that it is the magnetizing of pole piece and relay wear that is the problem. If it was a leakage to ground on the 6EV7 pin #1 lead you might think the set wo uld go into TX on its own (relay energize) every now and then, of which I have never saw it do. One other thing- I bought a nice TR-4 from a fellow, based on several pictures, but the photo angles, due to glare, covered up (of all things) a ham's DL # engraved on the front panel in tiny lettering , immediately to the right of TR-4 on front panel. Do you know of a touch up paint that matches the darker grey of that front panel area? I got the set for a decent price, it was nice and had the built in NB, but had a problem (as advertised). I found T-9 to be burned out in center area of coil form. I had a spare T-9 from a parts unit TR-3. Thank goodness I opened up the TR-3 T-9 transformer before I installed it -- it had a 56 pF cap in it that was not in the TR-4 T-9. Otherwise the coils looked the same. Anyway, I clipp ed out the capacitor and all went OK after the repair. That is not a fun repair for sure!! CUL, Byron. - Original Message - From: Garey Barrell To: Sent: Tuesday, April 29, 2008 1:46 PM Subject: Re: [drakelist] TR-4 TX Hang-Up Byron - Well things were going well until you pulled the tube out of the socket! :-) There are a limited number of possibilities in that case
Re: [drakelist] premizer alignment puzzler
Byron Tatum [EMAIL PROTECTED] made an utterance to the drakelist gang -- Hello Rich- One thought comes to mind -- Are you sure the crystal itself is oscillating and not the L/C circuit of adjusting coil? I believe in a previous message I saw frequencies listed, which were measured ,and they reasonably agreed with the crystal frequencies. But thought I would ask this first before ruling it out. Thanks, Byron WA5THJ. - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, January 22, 2008 2:03 PM Subject: [drakelist] premizer alignment puzzler [EMAIL PROTECTED] made an utterance to the drakelist gang -- I am in the process of restoring a TR-3. I've spent a great deal of time trouble-shooting the premixer, but I'm stumped. I'm about ready to throw my hands up and send it out for repair. I'm not too cheap to pay someone to help out with this, but I started restoring this rig to help become more familiar with tube transceivers and analog circuits. I hate to give up. The radio works well on 20 and 80 meters. On 40 meters, the premixer oscillator runs at 16.3 mhz instead of 20.5mhz. I get no power out. On the 15 and 10 meter bands, the crystals read low by about 100khz. Last night, I poked around with a scope a little more and tweeked the 20m crystal alignment inductor and suddenly the premixer was working. I had precisely 20.5mhz on 40m and the other bands measured correctly too. I found two leads under V3 that looked like they may have been shorted, so I blamed my problems on that. Emboldened with success, I proceeded to run through the alignment procedure. I went through the injection coupler alignment and on to the receiving IF alignment. Then everything went south again. Figuring that maybe I had a thermal issue, I turned the rig off and let is sit overnight. My hope was that this morning I would find the premixer working again. No such luck. I suspect that there may be something wrong with the alignment I did. I've double-and triple checked the steps in the procedure. I've poked around with an insulated tool to see if I could find a bad solder joint or cracked component. I've cleaned the band switch several times. The alignment instructions were written for folks who lacked modern test equipment. Maybe there's an easier and more precise way to align the premixer. If it isn't something I did, then there is something marginal or intermittent in the circuitry. I'll have to admit that my analog background is limited. I can use a scope and I'm comfortable with digital circuits. I have a good scope and know how to use it. I'd appreciate any pointers from the group. I know that Mark (N1VQW) is wrestling with his premixer too, so any tips would probably get double-duty. Thanks in advance Rich KE1EV -- Rich Carter -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net -- -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] WeakTR-3 transmit on 40, 15, and 10 meters
Byron Tatum [EMAIL PROTECTED] made an utterance to the drakelist gang -- Rich- Sounds like crystal osc not working, as TR-3 works without the premixer (VFO beating against crystal osc) on 80 and 20. Bad crystals are my #1 suspicion. Use a VTVM or high impedance voltmeter and check for oscillation (as described in manual): connect meter to Test Point and check for negative voltage (about -5 volts or so). If the crystals are oscillating then I would check voltages around premixer tube. If OK there I would adjust the injection coupler transformer for one of the bands just to see if someone diddled with it, but that is pretty remote there. I like to use the 6GH8A in place of 6U8 or 6EA8 for a little more kick in both mixer and premixer. CUL, Byron WA5THJ. - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, January 18, 2008 10:32 AM Subject: [drakelist] WeakTR-3 transmit on 40, 15, and 10 meters I'm restoring a TR-3 transceiver. I've cleaned it up, tested the tubes, and carefully cleaned the switch and relay contacts. I find that I'm able to get about 100 watts CW on both the 80 and 20 meter band. The receiver seems to work fine for these two bands. The other bands are very weak. In fact, I get nothing out on 40 meters and only about 1 watt max on the other bands. I suspect the crystal oscillator. I replaced the 6EA8 tube, things improved very slightly on 15 and 10, but still no power out on 40. There is a test point available on tube V1a. I put a scope probe on the test point, but I don't see a signal. Well, I see just some 60 cycle ripple on 40 meters. On the other bands, there may be a very small oscillation superimposed on that, but I can't tell. If I put the probe near the tube, I pick up what looks like an HF oscillation on 10 and 15 meters. Does anyone know what the signal on this test point should look like? On receive, the 80 and 20 meter bands appear good. I can receive strong stations on the 40 and 15 meter bands, but I think the receiver is partially deaf. I don't know how good the 10 meter band is. There isn't much activity on that and these days. I suspect the 40m crystal, but if it were bad, I would expect it to be totally deaf on 40m. I thought perhaps something might be wrong with the band switch, but I've cleaned it up pretty well. Any suggestions on how to proceed troubleshooting the transmitter? The rig came with a Collins hand mic. I find that I get poor audio when transmitting SSB (on the two good bands). I get a only a few watts out in SSB. I suspect that the mic impedance is wrong. There's a transformer in the mic. The element measures 4 ohms. I could possibly change the transformer or increase the mic gain. I'm reluctant to change the mic gain, but I think I could lower R94 to boost the signal. Anyone know what they put in these things for a transformer? Rich KE1EV -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
Re: [drakelist] Tube Subs --- Drake R-Line
Byron Tatum [EMAIL PROTECTED] made an utterance to the drakelist gang -- Hello All- My favorite sub for the 12BZ6 is the 12AW6. The 12AW6 is plenty cheap and plentiful. I can't tell the difference between them. Byron WA5THJ. -- Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net --
[drakelist] Drake 2B Parts Needed
Hello- I am restoring a Drake 2B and need these parts: 1 Main Tuning Knob 1 Dial Pointer ( long red one that slides with string drive) Thanks, Byron WA5THJ.
