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model 20 hum (detector circuit?)
#55

To check the interestage transformer for any leakage. Just look for any continuity between the primary and the secondary windings and the case. Something else to try. Lift the center tap off the B line and use a separate bias supply here for the 71s. This will verify that it is or is not coming from this transformer.   Just watch the bias on the 27.

!!!!!!!!!!!!!!!!!!!RESISTANCE IS FUTILE!!!!!!!!!!!!!!!!!!!!!!  
                           /\/\/\/\/\/\/\/\/\
                                                     
                                 [Image: http://philcoradio.com/phorum/images/smi...on_eek.gif]  Chris


Messages In This Thread
model 20 hum (detector circuit?) - by Tubesforme - 10-19-2015, 12:11 PM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-19-2015, 05:23 PM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-20-2015, 09:01 AM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-25-2015, 09:57 AM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-25-2015, 10:39 AM
RE: model 20 hum (detector circuit?) - by morzh - 10-25-2015, 10:08 PM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-26-2015, 09:18 AM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-26-2015, 09:34 AM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-26-2015, 10:24 AM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-27-2015, 07:43 PM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-28-2015, 10:52 AM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-28-2015, 02:36 PM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-30-2015, 05:13 PM
RE: model 20 hum (detector circuit?) - by OZ4 - 10-31-2015, 09:40 AM
RE: Low continual hum in model 21 - by Tubesforme - 10-23-2015, 10:19 PM



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