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Alot of problems with my radio...

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Alot of problems with my radio... Empty Alot of problems with my radio...

Post by Sprague on Mon Dec 22, 2008 9:02 pm

Hello people.
I have a Motorola 65T21, AM and SW. I turn it on, and it will work on shortwave for a half an hour or so. After that, it will fade in and out and, eventually, will stop playing. It has fairly low volume, lower than expected. I can get normal listening turning it about 3/4 of the way up. The static becomes very loud though. It can't barely get AM, but if I put my hand under the table beneath it, it will play more normal for AM. It will do AM better with no antenna, out of the cabinet. I can hear static when I turn the tuner around 6 megacycles, same spot on the dial for AM. I have a 20 foot long or so ant. to get more SW.
Am I seeing silver mica leakage here? I have replaced all of the other capacitors (electrolytic/paper) . Can that be detected with a capacitor checker?
Please get back to me here. I'm clueless. Good chance I'll have to take off an IF can...
Thanks,
Brian

Sprague
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Post by Resistance is Futile on Wed Dec 31, 2008 8:00 pm

Your tuner cap has a short I suspect, especially if you have it in the same position on both BCB and SW. Look and make sure that each of the plates have some air gap thoughout the tunning range.
Check tubes(maybe intermittant), all solder connections, dirty on off switch, dirty band switch, bad bias resistor on oscillator tube too high,
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Post by Resistance is Futile on Wed Dec 31, 2008 8:30 pm

If it plays with your hand close to the bottom I would suspect that the RF section has a loose antenna connection, RF coil connection etc. You are acting as an antenna. Also check AC voltage first then when the fading starts. Bad ac grounding?
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Post by Resistance is Futile on Wed Dec 31, 2008 8:35 pm

Also if it has a field coil it may be opening. pale
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