Pushbutton tuning problem - Printable Version

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+--- Thread: Pushbutton tuning problem (/showthread.php?tid=329)

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Pushbutton tuning problem - Guest - 04-19-2006

I have restored a Philco model 41-296. The circuitry in this radio is very similar to several Philcos made in 1940 and 1941. It has seven tuned circuit pushbuttons.

The radio works perfectly in all respects but one. Although the three lowest frequency pushbuttons are clearly labeled as tunable down to 540 kHz, I can't get any of them to go lower than about 640 kHz. They all exhibit this same problem.

The ceramic trimmer capacitors associated with these buttons are antenna trimmers only and have very little effect on the tuned frequency. They have a great effect on how well a station comes in after tuning it in.

It appears that, in pushbutton mode only, the local oscillator just won't tune low enough. Any suggestions are most welcome.

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- Terry Judkins - 04-19-2006

I don't have a schematic of the 41-296 but if it is similar to other Philcos of that vintage the fixed capacitor that is usually connected on the coil assembly in parallel with the coils is bad or has changed value. Most are 360 uuf. Replace it with a silver mica cap.

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