Home Forums Electronics Restoration Need help with Philco radio 37-361

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  • #6496
    dwhite
    Keymaster

    CVRS Member, Robert Cassidy is looking for suggestions for solving a problem.

    “I have a Philco Radio that I have tried to repair. When turned on it will only play for a few minutes before the volume slowly fades out. If I put my finger on (3A Ant) the volume returns. If any one could offer a repair suggestion, It would appreciated. In attachments I include the schematics. Thanks Bob Cassidy

    The schematic is attached.

    Attachments:
    #6511
    Peter Heembrock
    Forum Participant

    Check all the power supply voltages while the set works and when it does not…look for any major change…
    If some of the tubes are on the weak side this may affect the B+ voltage which may mess with the AVC circuit…
    If nothing comes from this then all I can suggest it to check all resistor values ( cold and after running for a while…freeze spray comes in handy sometimes for finding drifting parts.) I assume all the caps have been replaced.

    A tube may be weak or on the edge of being bad as well in the RF section…

    PH

    #6512
    Rob Uthe
    Forum Participant

    Also make sure the B+ isn’t too high and that the grid biases are negative. They may drift up if the plate voltage is high. Also, cathode bias resistors may not be working, so check their values.

    #6535
    Len
    CVRS Member

    Have you replaced all electrolytic and waxed capacitors? Check tubes? Measure plate and grid voltages? Are the tube shields in place?

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