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I am restoring a 48-206 leatherette I could not find the schematic so I used a 49-500 which seems identical to the chassis except for a couple bypass cap sizes, anyway, all caps, o.o.t. resistors were replaced. The radio reception is great for the first few minuts but hums like a bad filter, then the hum goes away but the reception gets weak and very distorted at the same time. the original filter calls for 30/25/20 I used 33/30/22 the voltage across the filters call for 115v/105v/90v to B- mine tests at 115v/90v/75v to B-. what would cause this voltage drop after it operates for about 5 min. All resistors and caps have been checked, filter caps have been substituted, feild coil is ok, tubes check ok and have been substituted with known tubes nothing helps. I have restored many AA5s with this same or similar chassis with no problems but Im lost on this unit and would appriciate any input or suggestions.
Thanks, Todd