Back in the 1970's, when my friends and I first started out in CB radio, we didn't have a lot of money to spend on equipment, so most of us worked our way slowly and (sometimes) painfully up from 100 mW Walkie-Talkies, to 1 watt (or more) Walkie-Talkies, to very modest 23 channel AM mobile rigs, and then eventually to a SSB rig, in various steps over a few years time. During that time period, we would peruse the various radio supply catalogs and admire those fancy, expensive rigs which everyone dreamed about owning, but didn't stand a snowball's chance in hell of affording back then. Radios like the Lafayette Telsat SSB-25, SBE Console II, Cobra 135, Pearce Simpson Simba, Hy-Gain 623 and others were my most common dream rigs. At the top of pretty much everyone's dream list though, were the Browning Golden Eagle, and the Tram D201. Both of these rigs were at the top of the premium list, and had price tags which were twice what most other full-featured, and already expensive, dream-worthy rigs had. The fact that, short of winning the lottery, most of us would never see equipment like this only made them all that much more irresistible and attractive. Their relative scarcity also tended to create a certain degree of mystique and legend surrounding these radios. It's an unfortunate fact of human nature that the more you can't have something, the more you seem to want it. Well, time marched forward, as it invariably does, and I've gone through quite a few different radios in my time, including some decent performing (and equally expensive) ham rigs like a Yaesu FT-101E, FT-757GX, and Icom 706. And after operating such technologically advanced radios, the desire to obtain one of those early dream rigs faded in the process. However, now that those 30+ long years have gone by, and I'm now waxing nostalgic, and revisiting those old classic CB rigs, I find myself about to realize one of my childhood dreams, as a once top-of-the-line Tram D201 is about to fall into my hands. But like many of life's other pleasures, this one also comes with a catch - it needs some (maybe a lot of) work to bring it back to its former glory. This should really come as no surprise as any electronic device, which survives a 30 year service life, is going to incur a few battle scars along the way. Adding to the list of potential problems, are those modifications performed by screwdriver "technicians", who often ignore good engineering practice in the never ending quest to make their rigs "louder", "stronger", and more frequency agile. Many of those mods can be detrimental to the life expectancy of the rig itself. So while I'm excited to finally operate something I once could only dream about, I'm also realistic (no, not Radio Shack!) about the very real possibility that this radio may never perform as well as it once did when it was new.
The realization of my long time dream came about totally unexpectedly though. I had started playing around with the old classic rigs that I had sitting in my closet, just for fun, and started extolling the nostalgic appeal of those old vintage tube rigs to the locals on the channel. The next thing I knew, at least 2 other people had started buying up old classic rigs from E-Bay. Art especially, had gone totally outer limits buying up Sonar, and Robyn tube rigs, including a hybridized 40 channel version, and even some not-so-classic solid state rigs. But during his buying frenzy, he somehow bid on (and won) a Tram D201 by mistake (He thought it was an even older Tram Titan), which needed work. He then found another D201 to use for parts. But the original rig turned out to be in worse shape than the supposed "parts" rig and neither rig is in operating condition. He soon found himself overwhelmed by the complexity of the Tram's circuitry. So now I get to put my talents to work in trying to get at least one of these wonderful old monsters working again. Me, being the radio optimist that I am, am not yet ready to condemn the "parts" radio completely and I will try to get that one working as well. But it's missing some key parts, and I'll have to find yet another parts radio (Which I'll also probably want to restore, so the cycle will never end....) or jury-rig some aftermarket parts to make them fit.
I was recently at Art's house to help him with a boat related project and while there, I picked up the two restoration candidates, which I nicknamed "Bad" and "Ugly". These names came from an inspiration I got the the other night, when some skip-talking redneck bonehead kept playing his obnoxious overmodulated noise-toy over and over, playing the theme from the movie: "The Good the Bad and the Ugly", which was annoying in itself, and forced me to run the squelch control a bit higher than normal. But like they say, every cloud has a silver lining, since it gave me the inspiration for the name of this project. The goal therefore, is that I will be able to garnish one "Good" radio from the combination of the "Bad" and the "Ugly".
First let's start by introducing the 2 rigs:
"Bad", was in somewhat decent physical shape, a few scratches were the extent of its exterior defects. It was sold by someone who was in the process of restoring it, but claimed he had lost interest. There were a few tubes, the relay, and some panel lights missing, and the power transformer looked as though it had caught fire on the bottom, as the insulation looked burned.
"Ugly" was in a little rougher physical condition. The top cover had a square hole cut in the top presumably to accommodate a cooling fan (I cringe at the mental picture of some yahoo taking a sawz-all to the top of this classic rig) and there was a chunk broken off of one of the woodgrained sides. It contained a fairly complete set of parts, but some of the circuit boards were blackened, circuits traces lifted, solder connections showing dull and overheated connections from excessive current draw (a result of someone's attempt at a power mod no doubt), as well as many band-aid repairs and modifications which had been performed over time trying to keep the rig alive. "Ugly's" power transformer had similar issues with a burned insulation wrapper, as it is now completely missing on the bottom, exposing the windings. When the Art powered up this rig, his room lights dimmed, and he quickly turned it off. It would appear that something major is shorted. Hopefully it's not the power transformer......
Art had taken the relay and some of the other parts from "Ugly" and transplanted them into "Bad", and when he powered that rig up, he thought he had some semblance of receive, but little else. So that's where I now stand. I will resist the temptation to immediately power up the rig, and instead work to clean up the boards, poor connections, switch contacts, and undoing poorly done modifications first. I began my anxious and equally daunting task by blowing the insides out with a blast of compressed air, followed by a manual dusting and spraying with circuit board cleaner. I also printed out the service manual and schematic for the radio, and started to familiarize myself with this unique hybrid circuitry. It would appear that there were a few revisions in these D201 radios during their history, and even my two rigs are different in subtle ways. "Bad" has a 3 pin grounded A.C. plug, while "Ugly's" plug is only a 2 pin. Adding to the confusion, the D201 schematic that I have, dated 1975, appears to be for the original point-point hand wired version, as it does not show the boundaries and connections of the various circuit boards. The D201A (40 channel) version, does show the board divisions, and is otherwise electrically similar. So I'll have to rely on both schematics to muddle my way through this mess.
The next day was spent cleaning up the low voltage regulator board (called the "Aux audio" or "BA" board). There were several fractured solder connections on the Molex plug, as well as blackened resistors and a tacked-on replacement capacitor. I replaced the questionable parts and repaired the solder connections. I also pulled out the other plug-in board and retouched the solder connections there as well. I also sprayed more cleaner on the PCB's and went to town repairing lifted circuit traces, and questionable solder connections. I also spent some time looking at "Ugly". I determined that there is a short in the HV power supply, which would explain the large current draw that Art saw when he plugged it in. While it seems more likely that I'll be able to restore "Bad", and may have to take some parts from "Ugly" to complete the task, I am still hopeful that I can get both rigs working at some point.
Day 3 started with me making some further checks of connections, but I wasn't able to continue on this path for long before I succumbed to my overwhelming desire to just fire it up and see what happens. So I placed the radio on my work table and plugged it in. Turning it on saw the panel lamps light as well as the tube filaments. So far no smoke, and after a few more seconds, I started hearing an A.C. hum from the speaker (at least I have audio). Keying another radio on the same channel, saw the S meter move and some feedback erupted from the speaker of the Tram. Great!, I thought, the receiver's working. But as I would find out, this project would not bring me satisfaction without a fight. I tested the power supply voltages and they were all present and within range, except for the 270V supply which was running well over 300V. So far, so good. The S meter was acting somewhat erratic and there was some intermittent static in the receiver along with it. Hooking up the signal generator showed that while the receiver was technically "working", it was not very sensitive, as I had to put in about 200uV worth of signal to get anything. Lack of background noise leads me to believe that one of the later I.F. stages or the detector may have a problem. To add to the growing list of issues, the manual tuner does not appear to be working either. But the worst problem turned out to be SSB receive, or should I say "no receive", as in it's completely dead. I tried a quick alignment, and that improved AM receive slightly, but it's still way down, and still nothing on SSB. I also swapped a couple of tubes with parts from "Ugly". I also swapped out the balanced modulator board as well (since it was plug-in). But so far, nothing helped the SSB receive. I haven't wired the mike plug yet, so I didn't try the transmitter, but I did set the final bias. I plan on trying the transmitter the next time, as it will help me isolate other problems. If SSB transmits ok, that reduces my suspect list as parts of the SSB IF are shared by both transmit and receive. I can also check to see if the manual tuner works on transmit (another popular mod), which can further shed light on this problem. I will also focus on the mode and tuner switches and the relay, and how the various voltages are switched depending on the mode it is in. The problems I'm having could be caused by something as simple as a missing voltage due to a dirty (or mis-wired) switch. I'm also going to check ripple voltages on the supplies and replace any filter caps, if needed.
The next night, I wired up the mic plug and decided to see how the transmit side of "Bad" was working. Surprisingly, the rig transmitted a strong 4 watt carrier on AM, with modulation. Switching the crystal/manual switch to the manual mode did not change the transmit frequency, which tells me the that VFO transmit mod had not been performed (or, as I would later find, not correctly). It also transmitted on SSB, although it appeared to be distorted or the crystal oscillator was off frequency. The AM modulation envelope was also somewhat strange and distorted looking. Attempts to neutralize the final to remove the spurious emissions were met with failure, although I was not able to perform the process per the alignment procedure, so when I revisit the transmitter later, I'll make a more comprehensive attempt. Operating the transmitter was done mostly to determine if the cause of the SSB receive problems could be traced to the Balanced Modulator board. Since the transmit and receive share components here, the fact that SSB transmit worked, pretty much eliminated this component as the root cause of the receive problem. I then decided to visit the audio hum issue. Interestingly, when the rig is first powered on, as the receiver is first warming up, the audio is crystal clear, then the hum pops in and is sometime intermittent. The usual initial suspect in a case like this, is a power supply filter cap. The voltages were checked for excessive ripple, and where there was a little more ripple than what I thought it should have, I tacked another cap across it to reduce the ripple. After the supplies were corrected, the hum was still present. Probing the audio output tube socket with the scope showed a fairly strong A.C. component on the cathode and plate. I am now wondering if my BRAND NEW 6L6 tube has a heater-cathode short, which is coupling the A.C. filament voltage onto the cathode......
Recap of "Bad's" remaining issues:
AM receiver working but weak.
SSB receiver dead.
Manual tuner dead.
Hum on receive audio.
AM TX there, but modulation distorted (Possibly related to the hum problem).
SSB TX is also working, but in need of an alignment.
Day 5 was a banner day for forward progress on the problems plaguing "Bad". I had decided to concentrate my efforts to resolving the receiver hum problem. I had at first thought that there might be a tube short coupling A.C. filament voltage onto the cathode of the audio output tube. But as I progressed down this path, I was able to determine that the hum was not being introduced in the final section. I traced the problem back as far as the volume control. A clue came when the transmitter was energized and the hum went away. Another clue was that the hum went away when the squelch was advanced. Swapping every tube in the audio chain did not resolve the problem. Becoming frustrated, I decided to take a different path and look into the weak AM receive. I noticed that the R.F. front end tuning was not very responsive, so I swapped out the 6BQ7 front end tube with the one from "Ugly". Surprise, surprise! Not only did the AM receive get stronger, but the hum vanished (Huh?). I would have never guessed that a bad R.F. receiver front end tube could introduce A.C. hum on the receive audio, but somehow it did, even with the volume all the way down. I gave it a quick alignment and discovered that one of the cans had a cracked slug in it, so I swapped the can with one from "Ugly". So when I finished the alignment, the receiver is responsive down to .2uV, which is real close to what I would expect, and the audio is clean. Another surprise came when I tried the manual tuner again, and found that it was now not only working, but the dial calibration was very close. Sensing the potential for a hat trick, a Trifecta, or a tick-tack-toe, three in a row, I optimistically switched to SSB hoping to see it now working as well. But alas, the SSB receive was still down for the count. The S meter also has some problems. I was able to zero the meter (Which seems to drift a whole lot more than I'd like to see), but I did not have enough adjustment range to set S9 with 50 uV of input signal. The meter needle will slam against the glass when I key another radio, so the meter has enough sensitivity. I am wondering if there is an AGC problem. But that will have to wait until the SSB receive is fixed (And who knows, the problem might be related). At this point, I could probably throw the rig on the antenna and debut it for the locals. But I think I'll wait until it's completely fixed first.
Updated remaining issues:
SSB receiver dead.
Align synthesizer and SSB TX.
Align and neutralize the TX final and driver tube.
Resolve the "S" meter issues.
Parts cannibalized so far from "Ugly":
Resistor from the Aux Audio board.
Balanced modulator board (But may be able to swap back)
455 Khz I.F. can.
Mic Gain knob.
Over the weekend, even more progress was made. I went to work on the SSB I.F. section by tracing signal backwards from the 1st stage. I soon found that a screen grid bias resistor on the 2nd SSB I.F. amp was open, which prevented the stage from working. It was odd for me to see a resistor (especially a 2 watt carbon resistor) actually open completely up without visible signs of burning. I think I've only seen this 2 other times in 30 years. Normally when a resistor opens, it has very visual signs of excessive current flow (I.E. it's burned). Replacing that resistor corrected the problem, and also loaded the +270 volt line back down to about 280V instead the 315V it had been running at. At this point I started to hear signals on SSB, but they were very low in volume. Further checking revealed that there were (2) 2N3904 transistors in the SSB AGC stage which were both bad. I had to wonder what killed them, and my best guess was that the +14V supply had jumped up due to the fractured solder connections I had discovered and corrected when I first inspected the regulator board. With the full unregulated 25V applied, the transistors died a painful death. Once the 2 transistors were replaced, and with one more alignment, SSB receive was finally working properly. Now that the receiver was complete (except for the "S" meter calibration), I set my sights on the transmitter. I performed the neutralization procedure and this time was successful. I also aligned the carrier oscillators and the carrier balance. I was not able to completely suppress the carrier, so I swapped the Balanced Modulator board back with the original board, and this time the alignment went fine. I then turned to the frequency alignment of the main synthesizer. I went through all the channels and attempted to set all the frequencies dead nuts on. After it was all said and done, I was left with 2 AM and 2 USB crystals which could not be adjusted on frequency. 3 of the 4 crystals had drifted low and one was high. Rather than trying to swap with the crystals from "Ugly", I decided to just change the fixed capacitors in parallel with the trimmer to give me additional adjustment range. AM transmit audio still looks a little strange on the scope, and I'll visit that again as I begin the final little clean-up checks to finally finish this radio off. I also swapped the two main tuner knobs from "Ugly" since they were in better shape. I also want to revisit the receiver's performance. While the sensitivity seems "ok", it is not outstanding, which is something I would expect from such a premium radio. I still suspect that there is either a tube which is a little low on gain, or that there may be other parts which have drifted out of tolerance. Considering all the current this radio's circuits draw, and all the heat it generates, caps drying out and resistors changing value is not out of the question. Add in the fact that the radio's over 30 years old, and it becomes very likely. It'll be a painstaking process though, since the sensitivity is already fairly good. Consequently, without a "perfect specimen" to compare to, it'll be hard to know which stages are performing within spec, and which are slacking a little. I'll probably swap tubes around, measure voltages and resistor values, and shotgun replace electrolytic or paper caps. In the process, I also hope to correct the ills of the "S" meter.
The next day I took a stab at trying to figure out why the "S" meter could not be set properly. Not being able to see anything obvious (Like a drifted resistor value) wrong in the circuit, I dropped the fixed 1M Ohm resistor in series with the S-meter adjustment pot to a 100K Ohm value. Once that was done, I could easily set the meter to the proper reading with a 50uV input. But I can't help but wonder if I had just performed a band-aid fix which covered up a different problem. Once the S-meter was set, I then checked the linearity of the signal scale, and I was a bit disappointed. It's not as linear as my Hy-Gain 623. It's linear between S-7 to about +10db over S-9. But outside of that range, it doesn't track properly. It's not nearly as bad as my Realistic TRC-451, and many other newer radio designs, but I just figured that a premium (priced) radio such as the Tram, would have a better "S" meter. I also swapped the R.F. Gain pot with the one from "Ugly", since it operated far smoother and with fewer dead spots. I also bought some NOS tubes from E-Bay to replace some of the aging ones in the Tram. Hopefully that will improve the overall performance.
I finally debuted the radio on the air for the locals. Everyone said that the audio was strong and the receiver seemed to be ok. I still want to play around with this radio a bit more. I want to try some different tubes, and I'm not all that happy with how much the "S" meter zero drifts, and I may try to modify that a bit.
On-the-air usage has also exposed another problem; the noise blanker appears to be inoperative. Further checking into this revealed that one I.C. and two transistors were bad. After replacement, I was able to align and observe the gating action of the N.B. circuit. But I haven't had any pulse type noise to "blank" to verify if the circuit actually does an effective job. During the rechecking of the rig, I discovered that the manual tuner was not working correctly. It would seem that when the manual tuner is selected, both the xtal synth and the manual tuner are active, which creates some interesting frequency mix products in the transmitter. I suspect that someone tried to perform the transmit VFO mod, but did not do it correctly. As I suspected, after a thorough investigation, it was a simple case of "mod gone horribly wrong". I corrected the problems, and now the manual tuner works correctly on transmit and receive.
A few weeks later, I changed out all 5 6GH8 tubes with NOS replacements. This has resulted in a slight improvement in receiver sensitivity, and more importantly has corrected the earlier issues with the "S" meter. The meter zero is now stable and it now tracks signal fairly linearly, as I would expect. The new tubes also put a little more kick in the transmit audio, as I now have to back the microphone gain back quite a bit from the earlier setting.
For the near term, I will enjoy this radio and hope that it lives up to the expectations that I had for all these years. As time goes on, I'd like to replace all the electrolytic and wax paper type caps, as I am sure they have all drifted with exposure to heat. I also want to check the value of some of the resistors which carry a heavy current load, so ensure that they haven't drifted. Replacement of the rest of the tubes is also a probability. But all in all, it would appear that I did manage to make one good radio from the combination of a "Bad" and an "Ugly" rig.
Total parts replaced:
1 455 Khz I.F. can
1 R.F. Gain pot.
Undid power mod.
Corrected VFO tuner mod.
Fixed numerous solder connections and P.C. trace breaks.
Tracked down and replaced defective parts.
Aligned whole rig.
And here it is, proudly running on my work table. It'll be an even more challenging project just to find a space on my operating table for this huge radio.....
But what ever became of "Ugly"? Don't worry, I didn't forget about it. In fact, that radio faired much better than I initially expected. I only had to steal a small number of parts, to restore "bad" and they were mostly cosmetic. So be sure to look for Part 2 to see how the "Ugly" project panned out.