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Philco 39-55 help
#1

Radio working. Replaced all caps. Radio still working, for 2 to 3 weeks, then low volume. Discovered missing voltage in power supply. Top of C42 has 350v but bottom of C42 at secondary CT has only a few volts minus. Transformer V and R checks ok. Resistor 41 checks ok. Field coil 43 ok. What happened? Also tried replacing C42 again but no help. Thanks for any suggestions.
#2

Hi oldtimer

Assuming you are measuring from point to ground, what you are describing is normal for condenser (42). The positive side of that electrolytic will measure around 350 VDC; the negative lead should read a fairly small negative voltage, on the order of 10 to 20 volts.

Time to check tubes. The 6Q7G may be suspect?

--
Ron Ramirez
Ferdinand IN




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