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Philco Model 20 escessive hum
#13

Did you replace the two .25 uF paper caps marked 14 on the schematic? These are in the long thin can under the chassis and provide additional filtering for the plate and screen of the 24 detector tube. 

If either one of these caps is open especially the plate supply filter, it will cause major hum in the audio.


Messages In This Thread
Philco Model 20 escessive hum - by Tubesforme - 03-25-2015, 03:52 PM
RE: Philco Model 20 escessive hum - by klondike98 - 03-25-2015, 04:17 PM
RE: Philco Model 20 escessive hum - by Mondial - 03-25-2015, 04:34 PM
RE: Philco Model 20 escessive hum - by Warren - 03-25-2015, 06:00 PM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-25-2015, 06:15 PM
RE: Philco Model 20 escessive hum - by Warren - 03-25-2015, 06:24 PM
RE: Philco Model 20 escessive hum - by Mondial - 03-25-2015, 07:02 PM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-25-2015, 09:09 PM
RE: Philco Model 20 escessive hum - by Arran - 03-27-2015, 12:01 AM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-30-2015, 12:11 PM
RE: Philco Model 20 escessive hum - by morzh - 03-27-2015, 08:52 AM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-27-2015, 03:25 PM
RE: Philco Model 20 escessive hum - by Mondial - 03-27-2015, 03:36 PM
RE: Philco Model 20 escessive hum - by morzh - 03-27-2015, 03:51 PM
RE: Philco Model 20 escessive hum - by radiohenry - 03-28-2015, 08:16 AM
RE: Philco Model 20 escessive hum - by morzh - 03-28-2015, 09:02 AM
RE: Philco Model 20 escessive hum - by radiohenry - 03-28-2015, 03:35 PM
RE: Philco Model 20 escessive hum - by klondike98 - 03-28-2015, 07:47 PM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-30-2015, 12:17 PM
RE: Philco Model 20 escessive hum - by radiohenry - 03-28-2015, 09:17 PM
RE: Philco Model 20 escessive hum - by morzh - 03-30-2015, 12:27 PM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-30-2015, 12:37 PM
RE: Philco Model 20 escessive hum - by morzh - 03-30-2015, 12:41 PM
RE: Philco Model 20 escessive hum - by morzh - 03-30-2015, 12:48 PM
RE: Philco Model 20 escessive hum - by codefox1 - 03-30-2015, 02:21 PM
RE: Philco Model 20 escessive hum - by Tubesforme - 03-31-2015, 02:14 PM



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