Philco fm radios - Printable Version

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Philco fm radios - Philcofan - 01-04-2021

Are these more difficult to restore. Interested in finding out your experience with them and if you would recommend them for a newbie to tackle. A couple on eBay now that I am looking at.

Thanks
Chris

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RE: Philco fm radios - morzh - 01-04-2021

I am working on one, 46-1213.
I am in the process of recapping. Will let you know once I am into the alignment.
I do not think it is very difficult. Same bunch of resistors, capacitors, coils and tubes.

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RE: Philco fm radios - RodB - 01-05-2021

Generally, FM uses the same circuits as AM from the detector back to the speaker. Get the AM working, then monitor the FM discriminator cap voltage, which is the small electrolytic at the FM discriminator diode. It's the AGC, equivalent to the AVC in AM. Send a carrier signal at the IF frequency to the FM front end and you should see the AGC voltage vary with signal strength. FM will use a separate set of IF transformers, often mounted in the same can as the AM, but the same tubes as AM. The band switch will select which transformer to use. Often the switch will cause problems.

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RE: Philco fm radios - RodB - 01-05-2021

Here's a YouTube link to a real good explanation of FM signal path and a simple way of doing the alignment: https://youtu.be/fNkDuEJjXm0

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