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Restored Philco 46-420 code 121 has slight low pitch hum.
#17

Not an expert here.
But I would like to suggest you check a few voltages before modifying the filter component, ( not that I'm beyond modification).
I'd check the plate voltage of the 50L6 first, . . . pin 3.  I see on the voltage list it's supposed to be 76 volts, but I wonder what it gets up to in these appliances that were originally designed for 110 volts a.c. It may be seeing as much as 125 volts from the a.c. line on mild weather days, these days.

This is something I intend to pursue with my 39-6 when I get to that point.  Somehow, I assume over-voltage would be of higher consequence with a unit having a power transformer, but the performance may be more-directly affected in these AC-DC units.   Icon_idea 

Jake


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RE: Restored Philco 46-420 code 121 has slight low pitch hum. - by Jake Blake - 03-19-2019, 08:25 AM



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