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Philco 36 660X IF trans - Printable Version

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Philco 36 660X IF trans - MICHAEL CHAMBERIS - 01-24-2026

My resto is progressing, Im in need of a 1936 660 chassis, or 665, 680 for parts. My 2nd IF trans was replaced and its destroying my signal transfer. can any 460khz if trans work?

RE: Philco 36 660X IF trans - Radioroslyn - 01-25-2026

The 660 2nd IF transformer is unique in that it's triple tuned where most are double tuned. This is used to sharpen the selectivity. As for using a replacement you can probably retune a 455kc can up to 460kc or grab a 460kc can. The only caveat is that it needs to be either an input or interstage transformer not the output. It's designed to match a low impedance diode load not a high impedance grid. Will it work as good as the original probably not. 

https://philcoradio.com/library/download/service%20info/service%20bulletins/Philco%20Service%20Bulletin%20223.pdf

ps Service note the local oscillator adjustment for the bc band and the pol band are reversed to the chassis pictorial. Drove me nutz for a long time as I couldn't get the top end of the bcb to align because I was adjusting the pol band trimmer.

RE: Philco 36 660X IF trans - MICHAEL CHAMBERIS - 01-25-2026

Thanks, Still chasing demons in the chassis. about to shelve it and move on but my OCD wants it to work. still looking for another chassis for parts but if a 455 will work it makes it easier.

RE: Philco 36 660X IF trans - MICHAEL CHAMBERIS - 01-25-2026

Apon further investigation, The replacement trans is 30 ohms per coil, cap #51 under chassis is missing.

RE: Philco 36 660X IF trans - DaleHCook - 01-26-2026

The resistance of a transformer, choke, or coil winding is useful for telling if a winding is open, shorted, or partly shorted. Other than that it is of limited usefulness.

RE: Philco 36 660X IF trans - MICHAEL CHAMBERIS - 01-26-2026

I mentioned coil res because on the print its listed as 3 ohms per coil. and the input trans has 30 ohm coils. Thought it might help determine it as a primary not secondary.

RE: Philco 36 660X IF trans - DaleHCook - 01-26-2026

Those resistances are only for troubleshooting. They need bear no direct relationship to parts values or configuration, and are likely useless for finding a replacement part. Back in the day radio repair shops could measure resistances, but not RF or IF coil or transformer winding inductances at operating frequencies.