10-28-2014, 08:54 PM
Fields,
Pull the chassis out, try to flex it a bit, see if this affects it. If yes, look for wires touching chassis, like filament wire maybe.
Try to see if the centertap of the B filament is grounded.
Check grounds.
Also try to see if another radio nearby with the same antenna type also hums. If you have a small tranistor radio, this is a good indicator.
Pull the chassis out, try to flex it a bit, see if this affects it. If yes, look for wires touching chassis, like filament wire maybe.
Try to see if the centertap of the B filament is grounded.
Check grounds.
Also try to see if another radio nearby with the same antenna type also hums. If you have a small tranistor radio, this is a good indicator.
