08-12-2009, 09:42 PM
Hi Folks,
I fixed a '56 Chevy radio a while back for a gentleman and he was so happy with it he brought me a '54 Chevy truck radio 986771 to work on. I re-capped it and the voltages and resistance chart were right on. However it suffered from low volume and crashing booming noises. I tracked the problem to the first IF transformer. I removed the can, gutted the internal capacitors and installed silver mica replacements on the external leads. After peaking that IF transformer at 262kc, the radio plays great but now I have another (I hope unrelated) problem. The dial tracking is not stable. I can tune it to a good strong station and after several minutes, the signal will suddenly disappear. I can turn the tuner slightly and find the same station again. It will play for several minutes and then the station will again suddenly disappear. The signal can be found again at its original position on the dial. I'm not too familiar with these inductive tuning mechanisms. Could the problem lie there or in one of the osc padders or even the second IF? The radio was really grungy inside and I cleaned it best as I could. Any opinions would be appreciated.
Thanks,
Ron
I fixed a '56 Chevy radio a while back for a gentleman and he was so happy with it he brought me a '54 Chevy truck radio 986771 to work on. I re-capped it and the voltages and resistance chart were right on. However it suffered from low volume and crashing booming noises. I tracked the problem to the first IF transformer. I removed the can, gutted the internal capacitors and installed silver mica replacements on the external leads. After peaking that IF transformer at 262kc, the radio plays great but now I have another (I hope unrelated) problem. The dial tracking is not stable. I can tune it to a good strong station and after several minutes, the signal will suddenly disappear. I can turn the tuner slightly and find the same station again. It will play for several minutes and then the station will again suddenly disappear. The signal can be found again at its original position on the dial. I'm not too familiar with these inductive tuning mechanisms. Could the problem lie there or in one of the osc padders or even the second IF? The radio was really grungy inside and I cleaned it best as I could. Any opinions would be appreciated.
Thanks,
Ron
