Tram D201Â Tweaks and Peaks
Modulation: Adjust R647
AM Power: Adjust C711,C712
ALC: Adjust R719
VFO Transmit Mod Remove Orange wire from relay and connect to PC board Ground
2) Install jumper from White/Blue wire on relay to White/Orange wire on relay
3) Remove White/Red wire from
D-125, Remove Anode end(no stripe) of D-126 from front wafer switch and connect to White/Red wire that was removed from D-125
The following information is from the credited source that may become lost forever if the website folds or other reasons as so much valuable cb information has been lost in the past fifteen years.
As I have a Tram D201 and need this resource I hope that the original owners will allow my indiscretion. If not contact me via the form.
http://www.worldwidedx.com/threads/tram-d201a.36369/
I have been searching the web to no avail trying to find out what the power, VFO transmit and audio mods are for a Tram D201 but I have found very little info.
Anyone have this info? I have two D201’s currently, one works pretty much as advertised but the other one puts out a carrier of almost 15 watts with a 6L6 which I am sure isn’t right. This one also has an internal squeal when the mic gain is above 12 o’clock but yet the squeal isn’t transmitted audibly and the squeal noise is still there even without a head on the D104. Makes no sense.
Anyone know about the 6146 mod?
#1LLFordman, Nov 3, 2009 Last edited: Nov 3, 2009
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The most common power mod, and the easieat to undo, is to jump the power resisters to bypass them. There are two resisters on the bottom side near the 6l6 tubr socket. Look for two identical resisters, and see if they have been jumpered. If so, remove the jumpers and you should be good to go.
PR
#2packrat, Nov 3, 2009
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Thanks much for the reply and the info. Had both radios on the bench side by side tonight. Radio “A” has a jumper on the 1.5k resistor and radio “B” has a jumper on the 2.7k resistor. That explains why “A” puts out 6 watts and “B” puts out 10 watts instead of the 3.8-4.2 watts the book states when neither is jumpered. I think the 6 watt output should be fine. Maybe more swing with the jumper removed though. We’ll see.
When I bought radio “B” it already transmitted on the VFO and radio “A” did not. I discovered tonight that radio “B” has a jumper and a wire removed on the crystal/manual switch. Is this part of the VFO mod to transmit? Radio “A” does not have this mod done to the switch, yet it still transmits on the VFO after I made a trace cut and jumper under the main board that I copied from radio “B”
Sorry if that’s difficult to follow. I wish I could find someone with drawings of these various mods.
Any thoughts on the squeal radio “B” is making? It changes when varying both the mic gain and the transmit tone control. That makes me think its in the first amp stage but I haven’t seen anything abnormal with the o-scope yet.
Thanks again for any help you can provide.
#3LLFordman, Nov 4, 2009
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You have to consider the age of the radios, your going to have Resistors that have changed value, failing capacitors, dirty/loose pins on tubes, lifted failing traces on the PCBs. All of the above is common issues. One or more are most likely causing your radios issues.
Checking components in the audio section would probably be a good start.
Here is some info regarding the various mods.
the 6146 mod is not difficult, I would however suggest an outboard amp over any internal changes.
#4MisterFatty, Nov 4, 2009
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Read through the linked thread for a bit of useful info as well….
http://www.worldwidedx.com/cb-band-cb-radios/36369-tram-d201a.html
#5MisterFatty, Nov 4, 2009
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LLFordman said: ↑
I have been searching the web to no avail trying to find out what the power, VFO transmit and audio mods are for a Tram D201 but I have found very little info.
Anyone have this info? I have two D201’s currently, one works pretty much as advertised but the other one puts out a carrier of almost 15 watts with a 6L6 which I am sure isn’t right. This one also has an internal squeal when the mic gain is above 12 o’clock but yet the squeal isn’t transmitted audibly and the squeal noise is still there even without a head on the D104. Makes no sense.
Anyone know about the 6146 mod?
Click to expand…
Have you checked Grumpy’s radio forum? If it’s still around there are more than a few guys on that site who know a great deal about the old tram radios. If you still cant get the radio worked out to your liking then contact electronic service center ( they have a web site ) in Elkin NC and ask them to put you in contact with Ray. He is one of,if not the best tech when it comes to the old tube radios on the east coat.
#6King Mudduck, Nov 4, 2009
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Excellent info! Thanks guys. I am going to go in further with the generator and comm analyzer (borrowing from work) tonight to try and see what the levels are starting at the first amp stage and working my way in. If it comes down to testing every component individually then so be it.
At this point both radios work quite well, save for the squeal on radio B. I am just a picky SOB and want it to work properly or as best as it can given the age.
I most likely won’t mess with the 6146 swap but will study the info just for my own knowledge.
I have browsed Grumpy’s forum in the past but didn’t find too much on the Tram D201’s. I will look again.
I’ll be sure to post my findings. More to follow.
Thanks again.
BTW, when the “squeal” is occurring, if you try to modulate through the squeal your voice sounds like it has a rumble in it. I am thinking AC getting in somewhere it shouldn’t be but haven’t seen any on the O-scope yet.
#7LLFordman, Nov 4, 2009 Last edited: Nov 4, 2009
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Check the BA board reall close. A lot of problems start there. Those caps get a lot of heat on them. Many folks change the resistor to cement type 5 watt. These should be carbon film or metal Ox. resistors. Wire rounds do not work well in this circuit and could possibly contribute to squeals and hows in the RX. The pins coming up from the board also come loose with vibration since there is nothing holding the board up but the pins.
At the base of the audio tube towards the back is a 2 watt resistor. Can not remember the value. But it goes bad quite often in these older rigs. I have seen this changed out in many units to the wrong value.
Also check the 10uf X 4 X 450 cap real good on each leg.
#8Radio Tech, Nov 4, 2009
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A bit of progress tonight. After grounding the ALC/Compression circuit per the alignment instructions, the “squeal” is completely gone and everyone says the radio sounds very nice. I tested most of the components in the ALC circuit and haven’t found anything faulty. Voltages are where they should be. At least I am in the right neighborhood now. I also removed the jumper for extra power and re-neutralized the driver and final so it is back to 4.2w out with a forward swing to 10-12w. Also noticed the noise blanker is inop as well.
More work.
#9LLFordman, Nov 5, 2009
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LLFordman said: ↑
Also noticed the noise blanker is inop as well.
More work.
NB was not one of the radios high points…
The channel selector must be on channel 9 when using the VFO. The clarifier will only change the XMIT frequency when in MANUAL position.
Yeah, they are great radios.
The 23 channel radio would be better with a Siltronix 90 VFO; but I’m sure someone will still want it for what it is and find the VFO themselves.
The 40 ch radio will sell faster, as it is a favorite for those that know their CB’s.
SO long as it works and it isn’t damaged, you should do all right…
#2Robb, Oct 1, 2009
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The Trams have a built in VFO which was usable in transmit mode with a simple mod, no need for an outboard VFO. the 23 channel covered 40+ no problem, and is easily modified for more. Depending upon where/to whom your selling the 23 (D201) channel can be more desirable and have more worth. It also depends where the radio was assembled.
The Tram 201A (40 channel) had a few trouble-spots, Channel Selector is probably the worse. there are a few common ones that plague both. Typical the most valuable Tram in the 201 series is the Hand wired version, which is also easily distinguishable from the others by its available Vox feature.
Depending on condition you could have anything from $75 dollar parts boxes, to 500+ dollar treasures.
Even if they currently work, the potential for costly repairs/parts replacement is very likely, mostly due to age.
Electrolytic capacitors, Under rated,Over-heated resistors, loose/lifted traces on circuit boards, bad tubes. These are among the common problems with a used D201.
Don’t let this put you off, the Tram is a desirable and excellent working vintage radio given proper maintainance and care.
#3MisterFatty, Oct 1, 2009
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Just to clarify, the D201 was 23 channel, and all D201A’s are 40 channel with the channel selector that went south. They are still popular, and will sell, but condition is the deciding factor.
PR
#4packrat, Oct 1, 2009
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cool beans guys. I have been beating around on the idea of getting them and going through em all the way. If nothing els, They might look nice on my shelf. What is the typical power out put on these, and frequ range?
#5sir. witchback, Oct 1, 2009
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Frequency range and power out would also depend upon mods that have been done to the radio.
Its been a number of years since I had a D201A, from memory transmit on the variable was up around 27.8-9ish, and a few below 1. the D201, I believe is about 27.6 and a few below 1. The 201 I have here has also had the common -1 mod done and with the flip of a switch goes down around 26.3 or so.
As for Power out, a good working 201 with good tubes could be made to easily run about 12 watts carrier, maybe 30-35 PEP. also another common mod which involved jumping some large power resistors to increase voltage. Many mods to the radios over the years, some even put 6146 in for the PA.
I would suggest forgetting about “Strapping” the power resistors, and leave it at stock voltage, leave the 6L6 coast along at the factory original output level which yielded 3-8 watts or so. My reason for suggesting this is the cost and difficulty in obtaining suitable 6L6 tubes. Which are in big demand by the audio guys Good RCA 6L6 tubes will easily bring $50 each, and they won’t get any cheaper….
#6MisterFatty, Oct 1, 2009 Last edited: Oct 1, 2009
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I would have to agree with leaving the radios output stock. They are getting older, and the parts were marginal when new, and will be strained by modification. Extra heat means extra problems. Besides, they are one of the best sounding radios to begin with, so why not just enjoy a Tram as it was meant to be.(y)
#7packrat, Oct 1, 2009
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Plan to change out some of the resistors on the printed circuit board models. They drift high and make the receive deaf.
The world is full of cheap 6L6s. There are certain suffix 6L6s which are sought after by audio pholks. You won’t need those types. That radio does indeed make a nice 12 watts and about 50 P.E.P. with one of those wirewounds jumpered. It can make 30 watts carrier if more are hacked across but the modulator does not keep up.
I put a pre-war 6L6 in mine just to be on the air with a 70 year old tube.
Any power mods need to be followed by adjustment of the AM audio compressor to keep negative modulation below 100%. The compressor circuit is very good. Find a good D-104 cartridge for best transmit audio. No preamp is needed. That will actually make the tone worse.
Noise blanker is pretty good.
Widebanding the thing will probably show up the usual CB radio bandwidth fall off problems. I have one on 10 meters and it works well across 300 khz then Po and receive start to roll off.
A rough estimate of the use of these rigs is to look at paint discoloration on the underside of the lid. The tOOb’s heat gets to the paint.
Best of luck.
#8HiDef, Oct 1, 2009
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Hey HiDef post a source for these “cheap” 6L6 tubes, american made? perhaps your definition of cheap is different then mine.
There is also a noticable difference in the audio quality of the radio with crappy 6L6, and some of those cheap russian/chinese tubes just don’t cut it…
I’d definitely not run a 201 that hard…. even at 12 watts the transmitted audio starts suffering without mods
Pretty much any of the US made 6L6 will bring 30+ dollars, and about 15% more if your willing to ship to Japan..
#9MisterFatty, Oct 2, 2009 Last edited: Oct 2, 2009
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Gotta say I love my Tram D-201 VOX radio. As far as an out of the box radio goes, this was the best sounding CB rig ever produced. Plate modulated audio from a 25 watt 6L6GC sure had Browning stumbleing to acheive the same audio and power output. The Tram still sounds good with the smaller of the two wire wound voltage dropping resistors shorted. Will key about 10 watts then with lots of PEP.
Thanks to Svetlana, the problems of locating a quality 6L6GC are over. Check out the SV6L6GC. The tube is about $35 and has been designed to be a winner. Heavy mica insulators, gold grid wires, and heavily coated oxide cathode really gives some stiff competition to the old RCA.
#10Shockwave, Oct 12, 2009
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Any power mods are almost guaranteed to cause trouble. Circuit board damage is almost guaranteed, and power supply problems are probable. Lots of these great radios died at the hands of uninformed modders. Look at all of the trams being sold on ebay with problems.Remember, these radios are getting pretty old, and were built with parts that were just able to do the job, and not much more. They work great as designed, so why do more that a good tune up?:confused:
PR
#11packrat, Oct 12, 2009
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packrat said: ↑
Any power mods are almost guaranteed to cause trouble. Circuit board damage is almost guaranteed, and power supply problems are probable. Lots of these great radios died at the hands of uninformed modders. Look at all of the trams being sold on ebay with problems.Remember, these radios are getting pretty old, and were built with parts that were just able to do the job, and not much more. They work great as designed, so why do more that a good tune up?:confused:
PR
Click to expand…
Packrat makes a valid point however it only applies to the D-201A made in Mexico. Just before Tram went out of business they tried to cut costs. The core on the power transformer used in the last radios made was 33% smaller in size and 33% less powerful. Evidence of this is found by looking at the power output stages of late model radios. The final tube was stepped down to a 6DG6 and a 10 ohm resistor was added at the final tube socket to reduce output.
This is certainly not the case with the older D-201. The radio was a powerhouse with a 6L6 modulating another 6L6 and a power supply with plenty of headroom. These tubes are about four times higher plate dissipation then the 6AQ5 or 6BQ5 used in any other CB output stages. With this in mind I have to disagree with this radio being built without extra headroom.
Most failures in the D-201 are related to the old carbon resistors changing value, filter caps drying out, and tubes gone bad. All of these problems can be greatly reduced by installing a small fan on the back of the rig. I can’t count how many Trams I’ve seen over the years with open resistors in the B+ line feeding the SSB IF RX tubes. I can count how many I’ve seen with a blown power transformer. It was a single D-201A in decades, made in Mexico.
I suppose it really comes down to what you are doing with the radio as to if you should mod it to do more power. For example if you’re driving an amp, 2 or 3 watts either way could make a huge difference in output, while being barefoot this power change means almost nothing. An old Tram with the full sized power transformer can easily make twice the rated carrier and still 100%modulate it without stress.
#12Shockwave, Oct 12, 2009
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Jumping the wirewound resistor to make the radio do 12 watts makes zero change in the power transformer’s load. The transformer delivers power to which is wasted as heat in the resistor or extra DC power input power to the final when jumpered.
If your D201 can’t fully and cleanly modulate 12 watts of AM/50 watts P.E.P. (with the resistor jumpered) it’s sickly and needs attention.
#13HiDef, Oct 12, 2009
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HiDef said: ↑
If your D201 can’t fully and cleanly modulate 12 watts of AM/50 watts P.E.P. (with the resistor jumpered) it’s sickly and needs attention.
let me make this a bit clearer, and this IS from experience, and was noted on BRAND NEW, fresh out of the box 201 radios.
Increasing output power beyond 7-8 watts carrier WILL make a noticable difference in transmitted modulation. Will the Tram 100% modulate A 12 watt carrier, yes it will, will there be a notable difference in transmitted audio between a 5 or 6 watt carrier, and a 12 watt carrier, YES there will be. Will this difference be recognizable by an average CB’er probably not.
#14MisterFatty, Oct 12, 2009
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I think what some people miss here is that these resistors are not just voltage dropping resistors. They are part of the Heising modulation circuit used in the radio. These resistors have an electrolytic cap across them for a reason. The resistors reduce DC power to the tube while the cap allows the AF modulation power to pass through without reduction. The overall effect is reduced carrier and increased modulation.
There is obviously going to be a balance here between the maximum carrier that can be produced while still being able to fully modulate it. As mentioned this limit is around 8 watts carrier. That’s why you should only bypass the smaller 1.5 K ohm 10 watt resistor if you need more power and not the 2.7 K 15 watt.
A previous post suggested that this will not place more load on the power supply since we are no longer wasting power as heat in the resistor. This is not exactly correct. You will place about 20% more load on the plate supply because without the resistor there is more current flowing. Less resistance means more current. Voltage divided by resistance will tell you that.
Some may find this hard to believe but I once modified a D-201 for a customer that produced a 35 watt carrier with 140 watts PEP! The final stage was still class C and plate modulated. I replaced the AF and RF tubes with 6146B’s and replaced the power transformer with one that made 600 volts DC.
I regulated the screen voltage on both tubes with OA2 voltage regulators, used a zener for cathode bias on the modulator and replaced the modulation transformer. Added an adjustable voltage regulator for the solid state pre driver so that the radio could have variable power too.
One thing I did overlook was the mode switch could not handle the extra B+ voltage across it’s contacts and flashed over on the first transmission! I replaced the damaged wafer in the switch and rewired it so a relay would switch between modulated B+ on AM and pure DC on SSB.
This modification is very labor intensive and took over 40 hours of bench time. The only reason I did it was because the customer said “money is no object if you can accomplish what I want! A thousand dollars later and one week in time produced exactly what he wanted 10 years ago. The radio is still working great today with no service time at all.
#15Shockwave, Oct 12, 2009
Shockwave said: ↑
I think what some people miss here is that these resistors are not just voltage dropping resistors. They are part of the Heising modulation circuit used in the radio. These resistors have an electrolytic cap across them for a reason. The resistors reduce DC power to the tube while the cap allows the AF modulation power to pass through without reduction. The overall effect is reduced carrier and increased modulation.
The D201 is not Heising modulated. The lytic across those 2 resistors keeps the resistors from wasting audio power. They only waste B+.
You are correct that the final will exhibit more drain from the xfmr by just bypassing the resistor. The plate load must be reduced (more capacitance) to where the plate dip will only give 12 watts out the pipe. This reduces plate current and most likely puts the rig where the modulation transformer ratio is optimum. It also puts the load on the power supply right back where it was at 4.1 watts out. The increased audio power needed to modulate fully will use more power but it’s less than 10 watts at low duty cycle.
The compressor must be re-adjusted to obtain just under 100% negative modulation after confirming correct audio polarity. If it’s only done on the bench with an audio oscillator the job isn’t finished.
I’ve always wondered how these rigs were ever type accepted. Maybe the ones built at the very end needed to be changed to continue certification. I didn’t know they changed the final toward the end. Interesting.
#16HiDef, Oct 13, 2009
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Yes, I agree that they can be made to make more power, but like I said before, it WILL kill the radio. Maybe not today, but soon. All that extra power produces extra heat. No way around it. Not a matter of if, but when. Heat will cook the already trouble prone, 30+ year old circuit boards, lift or burn traces, and cause all kinds of cool smoke. This is really why I still have my handwired D-201.:D
PR
#17packrat, Oct 13, 2009
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It seems as though I have misspoken about Heising modulation in the Tram. Without a modulation reactor this is not Heising. What I should have said was that the cap and resistor in the Tram form the same circuit that is used with Heising modulation to increase the audio level.
Hi Def, don’t you mean less capacitance to reduce load on the final amp? Adding load capacitance after increasing the plate voltage will kill the peaks. Besides, changing the plate voltage on an RF amp does little to effect it’s output load impedance because voltage effects current proportionally.
This is why Heathkit use to brag about being able to switch from tune mode to SSB on the SB-220 without having to retune. They simply cut the B+ by about 30% in tune mode and the current automatically goes down by 30% for the same drive level. This means output load impedance has not shifted.
Can I respectfully disagree that shorting the voltage dropping resistor will draw more current from the power supply at 12 watts output then 4.1 watts regardless of how you tune the PA? We certainly haven’t increased the PA efficiency by 300% so the only way around that fact is to draw more power.
As far as certification, I’m nearly certain that many of the changes we see in the D-201A are as a result of Tram needing to keep that certification. The smaller output tube, smaller transformer, added 10 ohm resistor, and screwed down lid are just a few.
At the end of the day, it is a better idea to leave both of these resistors intact. While the Tram does have headroom to make more power, any good tech will tell you to leave that headroom there to reproduce audio peaks. That is the reason the Tram has such a good following with it’s audio quality.
#18Shockwave, Oct 13, 2009 Last edited: Oct 13, 2009
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Class C R.F. amplifier with Pi net reducing the load capacitance will increase the load and current drawn by the tOOb. It does look incorrect but that’s how it works.
With class C you can load heavier or lighter looking for a certain load impedance to match a modulator. Class B is usually loaded for max smoke.
Yes, I’ll agree that more power will be drawn by only bypassing the resistor without reducing the load. The radio will also make more than a 12 watt carrier before changing the loading. I have one here and really don’t remember which resistor has been bypassed. What I do remember is the modulation percentage at 12 watts. It’s fine. My point is that the resistor will waste 10 or so watts in heat which can be applied to the final. Done properly it won’t make your radio fall apart or cause itching and burning.
Another thing to look for if modulation percentages fall off is lack of grid current in the final. Wimpy drive can be one cause.
Question: What color stain is a match for the woodgrain sides?
#19HiDef, Oct 14, 2009
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Quantity does not always equal quality… with the ready availability of outboard amplifiers, and the small gain, I see no valid reason to run the old radios beyond 6-8 watts carrier.
To each there own I guess….
#20MisterFatty, Oct 14, 2009
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I’m talking about a mod I came up with well over thirty years ago.
Again, If your D201 cannot make 50 watts P.E.P. with a 12 watt carrier there is a problem somewhere.
12 watts is a nice drive level for an SB220. 4 isn’t.
See you when 10 meters opens.
#21HiDef, Oct 14, 2009
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Well, that is why God made Kenwood!:LOL:
#22packrat, Oct 14, 2009
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HiDef said: ↑
Class C R.F. amplifier with Pi net reducing the load capacitance will increase the load and current drawn by the tOOb. It does look incorrect but that’s how it works.
With class C you can load heavier or lighter looking for a certain load impedance to match a modulator. Class B is usually loaded for max smoke.
Yes, I’ll agree that more power will be drawn by only bypassing the resistor without reducing the load. The radio will also make more than a 12 watt carrier before changing the loading. I have one here and really don’t remember which resistor has been bypassed. What I do remember is the modulation percentage at 12 watts. It’s fine. My point is that the resistor will waste 10 or so watts in heat which can be applied to the final. Done properly it won’t make your radio fall apart or cause itching and burning.
Another thing to look for if modulation percentages fall off is lack of grid current in the final. Wimpy drive can be one cause.
Question: What color stain is a match for the woodgrain sides?
Cherry Oak or what is referred to as Gunstock…
Remember that those are Laminated..
John
#23Dealer, Oct 14, 2009
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Thanks John.
#24HiDef, Oct 14, 2009
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MisterFatty, AMEN Bruddah, Warlock35po.
#25Warlock35po, Apr 3, 2010
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hey guys i have a d201a i have been fixing , i got everything back transmitting but the s-meter is still not right . i have the negative voltage at the meter thats it . is there a common problem , any suggestions?
#26idjjoker1, May 20, 2010
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In the Tram D-201 series radios the “S” meter is driven by a pair of 6GH8 tubes. First confirm the “S” meter is not pinned against the left hand side. If it is, adjust the calibration control near the relay to zero the meter with no signal present. If that’s not it check the two tubes. If that’s still not it you probably have open resistors or shorted caps in the circuit. The Tram is noted for having resistors that feed B+ to the tubes open up. Mostly on the SSB 6BA6 IF tubes and not the meter. I may be wrong but I think they added some solid state parts in the D-201A meter to help stabilize it and that may also be the problem.
#27Shockwave, May 21, 2010
http://www.copperelectronics.com/discus4/messages/14/45075.html?1058419682
No, the mike is not needed to receive on this radio. I DO hope that it’s a 23-channel D201 and not the 40-channel D201A. The channel switch used in all but a few 201A radios is a complete disaster, and wears out in a very decisive way after very little use. Most of the “mint” 40-channel Tram radios you see were put up on the shelf before a full year of wear-and-tear could occur. The channel selector would fail, the factory closed, warranties expired and the radios went onto a shelf with little use on them. The average price to fix the 40-channel switch was $175 twenty years ago, and has only gotten more expensive since then.
You did not mention if the S-meter shows any activity when you change channels. If the S-meter is laying dead, and doesn’t flick around from channel chatter, you will probably find more than just one problem with the receiver section. It’s a little like finding a 1974 Olds 442 under a tarp with 5000 original miles, but with NO service done to it since 1974. You can’t just jump into it and drive to California. There WILL be maintenance issues, plenty of them. It’s not JUST the miles, it’s the years, too. There won’t be JUST an adjustment screw or two that will get that Olds to California.
Any serious effort to put a D201 on the air for regular use will call for a “100,000-mile tuneup” even if it has very few actual ‘miles’ on it. Since all the two dozen or so electrolytic capacitors are on borrowed time after 25 years, a “scorched earth” procedure to replace every one of them is just ths start. The D201 radios have some heat issues with the wattage rating on about a dozen power resistors inside. Makes the color bands fade and bubbles to form on the surface. When that happens, the electrical quality of that part fades with the color bands. Most of those dozen resistors get replaced with larger ones that will run cooler, and longer. Leaving the old ones in can wear out tubes prematurely, or just prevent it from performing.
The relay is rare and expensive. It can make any part of the radio drop out when it goes bad. Crystals can fail from age alone after 25 years. Tube sockets (in the circuit-board versions) get loose with heat exposure. The rotary switches use silver-plated contacts. A long period of storage can allow black tarnish to build up on switch contacts and make any part of the receiver (or several parts) roll over and play dead.
On a more positive note, the original owner’s manual had a section on troubleshooting that wasn’t half bad. It did assume that a WORKING radio had just started to act wrong, and would suggest what to try first. A radio that may have six or ten separate problems is a whole different kind of troubleshooting.
As far as the idea of ‘turning up’ the receiver? There are about twenty adjustments in the radio that affect the receiver. Some of those also affect the transmitter performance. This doesn’t include the trimmer caps that set the channel crystals on frequency. Turning up the receiver means getting all of those adjustments peaked correctly.
BTW, the preferred mike to use on this radio is a STRAIGHT unamplified D-104. The amplified D104 will do okay, but has to be turned ‘wayyyy down, and won’t sound as good when you talk up close to it. That’s what the factory packed in the shipping carton with a new radio: a straight D-104. Just make sure the pickup element (cartridge) in the mike head is not old and weak. They tend to get that way around 20 years, even if stored in a cool, dry place, sooner in humid surroundings.
Good. It’s a 23 channel. A low-miles 23-channel is much harder to come by. They just didn’t “die young” like the 40’s did. Wear and tear take their toll. If the thing looks at all cruddy, removing the tubes and washing them in ammonia-base window cleaner, or such will remove whatever “insulation” is stuck to the outside of the glass, AND will shine up the metal surfaces of the pins. Rinse them in water. Be sure to dry them thoroughly before powering up. This is better done one at at a time. There are five 6GH8A tubes and three 6BA6 tubes in the radio. If you don’t return the same tube to the same socket it came from, that could affect the alignment. That’s one of the main reasons those “peaking” adjustments are there. The manufacturing tolerances from one tube manufacturer to the next will affect just where the “peak” will occur on those tuneable slugs. Scrambling the tubes around can change the calibration of the Manual tuning dial, the S-meter zero setting, and receiver sensitivity.
Tubes that make scratchy noises when tapped may have tarnished or loose pins in the tube socket. A NON-RESIDUE contact cleaner is worth trying, if the socket still grips the tube pins. If the socket feels loose, squeezing them back together with a pointy tool to tighten them is only a temporary fix. After thousands of heat/cool cycles, the metal in those socket pins loses its spring temper. When that happens, the socket just has to go. A radio that was run 24/7 will get hot enough to make the black plastic tube socket insulator crumble and crack.
Note that there is only ONE version of the BA board to match a 23-channel radio. The 40-channel was made with TWO different, non-compatible versions. A mismatch of the wrong BA board/radio can either cripple the audio power, or cherry the audio tube the moment it warms up, popping a variety of parts before it cracks the glass and kills the main AC fuse. If you are offered a 23-channel Tram D201, and the BA board has jumper wires where the left-side resistors fuse/capacitor belong, DO NOT power it up. A 40-channel D201A MIGHT well be built to take that board, and will have an unmarked trimpot on the SOLDER side of the main AUDIO board if it was. The BA board with the jumper wires will SMOKE a stock, unmodified 23-channel D201. Guaranteed.
The soldering on both sets of “auxiliary” board pins, under each main board bears checking closely. For whatever reason, the factory soldering would go bad on both sets of these pins, underneath each main circuit board. Resoldering with a good-quality rosin-core solder will usually do the trick, unless heat has begun to lift the foil traces.
One last thought. Does the guy with the new BA board (uh, TramDoctor?) also supply new PINS to go on the main board, and plug onto? If not, they are worth getting. The round pins that Tram used for the BA board have a wear problem. The plating on the round pins will just scratch off, eventually. Square pins can be had that will hold up better. Besides, they have bright, new shiny plating on them. If a NEW BA board has ‘scratchy’ noise problems when jostled, those old, round pins may be worn. If someone tried to SCRAPE those pins clean with a knife blade or abrasive, the solid-pin metal exposed by removing the electroplate will get tarnished and noisy only a few days after cleaning with solvent.
