03-06-2014, 09:35 AM
Greg, did you check here?
http://www.philcoradio.com/tech/60evol.htm
Ron has just about all the variations of the 60 schematics. I believe you have the later version if the 6A7 and 78 have individual cathode resistors instead of the earlier single combined resistor.
Voltage readings should be similar on all models. I would expect about 250 v on the plates with 90 to 110 on the screens of the 6A7 and 78.
Do you notice a big difference in AVC voltage on each side on the 2 meg AVC filter resistor? There may be something loading down the line on the side connected to the coils and tube grids. With a 2 meg series resistor it doesn't take much to pull the voltage down.
http://www.philcoradio.com/tech/60evol.htm
Ron has just about all the variations of the 60 schematics. I believe you have the later version if the 6A7 and 78 have individual cathode resistors instead of the earlier single combined resistor.
Voltage readings should be similar on all models. I would expect about 250 v on the plates with 90 to 110 on the screens of the 6A7 and 78.
Do you notice a big difference in AVC voltage on each side on the 2 meg AVC filter resistor? There may be something loading down the line on the side connected to the coils and tube grids. With a 2 meg series resistor it doesn't take much to pull the voltage down.
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