Tram D201 Intermittant Receive AM Only

[cricket]

Hello, I have a Tram D201 with a receive problem. What happens is that it will fade and then act normal again. If I touch any metal part on the radio when the rx is weak I will hear a static discharge 'pop' thru the speaker and the recieve will function normal again, at least for awhile anyway. Also, at times if I key the radio or switch from AM to either sideband the receive will be normal for a while and then fade again.

What I have done so far is replaced all electrolytic capacitors and replace all tubes in the receiver board with nos tubes as the old ones showed low emision or shorts on my tester.
Also I've resoldered numerous connections including tube sockets on the receive board and I still have the same problem and the voltages are well within normal.
Please note that the problem is with AM RX only.
And last I measured the resistors on the BA board and they are fine.
Any help will surely be appreciated.
Many thanks.

-Patrick aka Cricket

[gator7]

Is it a signal fade? or audio fade with a steady signal? I am thinking a AGC/RF problem??

[Sandbagger]

Jan 3, 2013 21:00:44 GMT -5 cricket said:

Hello, I have a Tram D201 with a receive problem. What happens is that it will fade and then act normal again. If I touch any metal part on the radio when the rx is weak I will hear a static discharge 'pop' thru the speaker and the recieve will function normal again, at least for awhile anyway. Also, at times if I key the radio or switch from AM to either sideband the receive will be normal for a while and then fade again.

What I have done so far is replaced all electrolytic capacitors and replace all tubes in the receiver board with nos tubes as the old ones showed low emision or shorts on my tester.
Also I've resoldered numerous connections including tube sockets on the receive board and I still have the same problem and the voltages are well within normal.
Please note that the problem is with AM RX only.
And last I measured the resistors on the BA board and they are fine.
Any help will surely be appreciated.
Many thanks.

-Patrick aka Cricket

There are a couple of gremlins in the PC board versions of the D201(a). The biggest one is the tube sockets losing grip on the pins, causing intermittents such as what you've described. I've also had problems with the connecters to the "AA" board. My D201's receive cuts out occasionally, and all I have to do it move that board slightly and it pops back in. I've touched up solder connections to the molex connectors, and cleaned both sides, yet the problem persists.

[Deleted]

I worked on one that had a couple resistors high or open. I think they were 470K. Replaced them and the RX came back.

If you have carbon resistors still in there, replace them with film.

Deoxit on the tube pins should help with the popping noise.

Not a fan of those radios. The engineer knew nothing about heat and heat dissipation.