The PHILCO Phorum

Full Version: 49-906 FM hum
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
I just finished my 49-906. Replaced all caps, out of range resistors and a few tubes. Alignment was done also.
AM is good and strong-no hum. FM picks up a few stations but has a hum all across the dial. It does almost go away when tuned to a station.
What did I miss?

http://www.nostalgiaair.org/PagesByModel...013675.pdf

Thanks,
You might try changing the 14F8 converter tube. If it has heater to cathode leakage, then the AC voltage for the filament will FM modulate the oscillator, causing a hum. It could also be the 19T8 tube, since different diode sections are used for FM.
Thanks, I'll try a swap and let you know.
That did it! The 19T8 made a difference.

Thanks, Mondail,