Tram D-201A slow receive

[40sx]

I got a question that I've been trying to find an answer to for a few years now. I have a few Tram D-201s and I'm pretty familar with them. I have one that the receiver will not come on until after the units been on for 5 to 15 minutes. This is very intermittant and only occures in the crystal mode and not in manual. It seems to fix itself if I use a small heat gun near the rear of the synthesizer board. I couldn't begin to tell you how many componets I've replaced in that area of the board. It may work for weeks on end, then the problem re-occures. After it begins to work, I cannot make this problem re-appear even if I try using freeze spray. I'm starting to believe that there might be a bad winding in T 101, I don't know.

Are there any sugestions to try when this decides to act up once again? What is not associated with the manual VFO compared to the crystal selector? I just had to ask because something like this can drive a person up the wall. BTW, I also own a few Brownings, I have a thing for tube radios.

Thank you in advance for any insioght into my problem.

Dennis

[Sandbagger]

Aug 4, 2008 15:43:02 GMT -5 40sx said:

I got a question that I've been trying to find an answer to for a few years now. I have a few Tram D-201s and I'm pretty familar with them. I have one that the receiver will not come on until after the units been on for 5 to 15 minutes. This is very intermittant and only occures in the crystal mode and not in manual. It seems to fix itself if I use a small heat gun near the rear of the synthesizer board. I couldn't begin to tell you how many componets I've replaced in that area of the board. It may work for weeks on end, then the problem re-occures. After it begins to work, I cannot make this problem re-appear even if I try using freeze spray. I'm starting to believe that there might be a bad winding in T 101, I don't know.

Are there any sugestions to try when this decides to act up once again? What is not associated with the manual VFO compared to the crystal selector? I just had to ask because something like this can drive a person up the wall. BTW, I also own a few Brownings, I have a thing for tube radios.

Thank you in advance for any insioght into my problem.

Dennis

Well, I can't tell you exactly what IS wrong, but I can eliminate what ISN'T wrong. If the receiver works all the time on VFO, then it's not T101 since that is common to both crystal and VFO modes. It would seem the most likely culprit for your problem is Q100 or one of the associated components, as that is the 4.0 Mhz crystal oscillator. That is the only circuit that is used strictly in crystal mode.

It's also remotely possible that something in the 16 Mhz crystal circuit could be switched strangely due to dirty switch contacts or a poorly done VFO mod. But I'd zero in on the Q100 circuit first.

[40sx]

Thank you Sandbagger. I have to find my parts list of the componets that I've already swapped, I don't think Q100 was one of them. Problems such as this can make a person pull their hair out. Other than this, this D201A is perfect electrically and cosmetically.

Thanks again,
Dennis

[2600]

You might want to check the 14-Volt DC supply when the radio is cold. If it's running low, this can affect the crystals in the channel synthesizer.

73

[40sx]

I will also check the 14 volt supply the next time I have it on the bench. I know I did work on one of my Trams "BA" boards several years ago and re-capped and installed flame proof resistors, but I believe it was the D201A that was in a flood, lol. When you get to be my age, sometimes its a little difficult to remember. Most of the time I keep pretty good logs. If the voltage is low, it will probably be an easy fix.

Thank you for your assistance,
Dennis (AA3SX)
73
BTW, I was very found and into CB long before I ever knew what ham radio was.