Tram D201 caps

[Hawkeye351]

These operators are slowly starting to push tube type radios on me, lol. Problem is, I know nothing about how a tube radio works. But that's never stopped me from accepting the challenge.

This 201 is not the hand-wired 201. It's the second release 201.

Issues:
1. Loud hum in receive speaker, constant hum, does not get louder with increased volume though.
2. Receive low in all modes.
3. Meter stuck all the way to the left, it will come up slightly with strong incoming signals, and barely comes up when Transmitting.
4. Variable power control strapped across the two cement power resistors.
5. VFO transmit mod has been done previously by someone else.
6. VFO dial is way off from crystal dial.
7. Previous tech installed a 120v AC fan, with an on/off switch.
8. Knobs increase/decrease in value erratically.

Radio does transmit. Although it does seem to be way too much for this old rig.
AM - variable all way down - 5.5w key swing to 24w pep. Variable all way up - 8w key swing to 35w pep.
SSB bout 30w swing. Everyone says it's extremely loud, but yet crystal clean on audio.

The owner gave 150 for the radio. He then bought all new tubes for it and retubed it, thinking it would solve some of his issues. He did test all the tubes he removed and they all were in very good shape, he replaced them anyway with the new ones. He then got in contact with me.

I'm thinking electrolytic caps need replacing, all high wattage resistors replaced and an alignment.

My question is:
Does anyone here have an e-cap list of all the caps in a 201, or the most well known culprit caps that should be replaced?
Also, where would I get the power supply can caps (2 silver can caps) in front of AC transformer?
Any 201 recap kits available?
Any other tips/advice for an amateur tech that knows nothing bout tube rigs, except that they're high voltage, lol...

 

[nomadradio]

Years ago I had our procedure posted, probably at Grumpy's forum. It was the routine we used 20-plus years ago. As such, it would refer to resistors we had bought in bulk, some of them in parallel pairs. These days we just buy the correct value from Mouser.

With any luck your BA board, plugged in next to the audio tube hasn't been pulled out enough times to wear out the plating layer on the header pins. When the plated layer wears off, you get the 'crackle' noises any time that board gets disturbed. We sell a BA board with new pins on fleabay. I use a 500-Volt 2-section filter cap sold for guitar amplifiers. The tall can has three sections, wired as if only two. If you use a dual 100uf+100uf part, this improves the filtering just a little over the stock setup. Here's one supplier. https://www.parts-express.com/100uF...ectrolytic-Mult-Section-Can-Capacitor-020-608

You'll need a mount clamp, but they have that item, too. As a rule the screw holes in the clamp will line up with the rivets that held the old cap's mount plate. Drill out the rivets, and mount the clamp with two screws/nuts.

For the short 4-section 'can' filter we just use four 10uf 450 Volt radial-lead caps. Three of the four sections of C624 have a single wire attached. We follow this wire to its other end and install the radial cap where the other end of the wire was soldered. The fourth section has two 7-Watt resistors attached. We use a single tie point with its foot soldered to the adapter plate. It gets the two resistors and one radial 10uf cap soldered to it.

Don't think we ever put together a procedure with pictures for this.

Mileage is everything. Power resistors with faded color bands reveal high mileage. Those have to be replaced. Preferably with more-modern carbon-film or metal-film or wirewound resistors. The relay is a potential issue, and cleaning it with thin strips of paper is incredibly tedious.

The tube sockets on the circuit boards are prone to wear out and become loose. A loose tube socket will cause no end of aggravation. Replacing them is a chore I remember posting a how-to on this forum. Gotta get better at searching old posts.

The S-meter is balanced between one section each of two separate tubes, V602b and V401b. Unless these two tubes are a close match in performance the meter will either fail to set zero, or drift constantly. Any time one of those two tubes gets replaced with a new one, the other one of the two should get replaced at the same time. A new tube usually won't balance well paired with an old tube. Two old tubes will work until one of them breaks down for good. A drop of control cleaner on the zero trimpot R422 may prevent the need to replace it. And if it won't stay set to zero, R422 is only one of several possible causes.

Restoring a D201 to be a reliable daily driver involves a lot of detail, but can be done. Just won't be cheap.

Here's an older thread on this subject. https://www.worldwidedx.com/threads/tram-d201-40yr-100-mile-restoration-done-right.260134/


73

 

[nomadradio]

Hmm. Had a humorous thought. Any procedure or advice for restoring a D201 should have a graphic with the international "prohibited" symbol, the red circle with the diagonal bar across it. Behind that is a pic of a garden hose with spray coming out.

NOT a garden-hose radio.

73

 

[Hawkeye351]

Great info, thank you nomad.

 

[Hawkeye351]

I've seen a ham operator once take an sb220 and spray the inside (top and bottom) with simple green, then proceeded to use a water hose to clean the inside, lol.... People do some silly stuff.

 

[Hawkeye351]

I put this one on the shelf until I can gather all the caps and resistors, plus so I could get some of these others done while I'm waiting for parts.

The realistic 457 is on the back burner also.