[45philcodon]

I've just finished restoring a Silvertone Model 1908. Reception is good BUT off-station the radio is very noisy (squeals). Once a station is tuned-in, the radio is reasonably quiet. However, tuning is difficult; that is, very narrow "quiet" range requiring very precise, delicate tuning to quiet radio. The squeals seem worse at the high end of the AM band.

Any suggestions would be welcome.

Thanks,

Don

[Radioroslyn]

Sound like your IF amp is oscillating. Try touching the grid cap on the 6K7 and to hear if it clears up. May drop the gain a bit. If so realign the IF transformers if it still persists detune one of the IF trimmers.

[45philcodon]

Thanks, I'll try that.

Don

[Jayce]

Actually, this sounds like the exact issue my RCA 19K developed. Sounds like it needs the same thing done to it for the problem.

[45philcodon]

I'm sorry, I am not familiar with what you did for your RCA. Could you elaborate?

Thank you,

Don

[Jayce]

I haven't done anything for the problem yet. I was just mentioning that my RCA seems to have the same problem, really noisy between stations and hard to get tuned in just like your Silvertone. So, I am hoping the solution mentioned will work for both of us.

[45philcodon]

OK, thanks. Here's hoping.

[Arran]

There may also be an issue with the AVC bypass capacitor, it could be open circuit or missing. Another thing to look at are grid caps and grid cap leads, sometimes the solder joints on the grid caps get flaky, as does the solder joint on the clip that goes on it, the wire can also break internally. Another source of oscillation can be the first audio tube, if it is a glass type like a 6Q7G or a 75 they cause a squeal with the shield removed.
Regards
Arran

[45philcodon]

Thanks, Arran. I'll get into troubleshooting tomorrow. I'll post what I find.

Don

[45philcodon]

The AVC bypass cap was in-circuit and correct value per the schematic. However, increasing the bypass cap value quieted the radio substantially. Tuning is now much easier and the audio is cleaner once tuned. The radio now performs as I expect it to.

Thanks for the tips,

Don