Quote:
Originally Posted by Electronic M
Heck of a lot to respond to there....
Quick hum diagnosis tip. If you can disconnect the B+ with a lytic still in circuit giving a couple secs B+, but keep the heaters going on AC if the hum persists when the B+ is disconnected from AC that indicates heater/line cord hum leakage (or perhaps field coil issues if it does not use a PM speaker).
If hum seems to be in the heater circuit try unplugging the set and see if it hums for the second or two it runs with the plug pulled.
Standby usually cuts off B+ while leaving heaters on. If audio/hum persists in standby then there is something wrong with the standby mode.
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There could be a H-K short in one of the tubes.
The circuitry is the same as the earlier Hallicrafters models, except for the rectifier circuit and heater drop. The year earlier models used a 35W4. Why they did it that way is anyones guess! It couldn't have been a cost savings.
The Hallicrafters sets of this type were very insensitive on the high band.
IIRC, in that model, the standby switch will only cut the B+ to the plates and screens of the converter and IF tubes.