1935 GE Model A-53 AM/SW Tombstone Radio

[old_coot88]

Sounds like there might be a 'floating grid' condition with the 6A8. That's when the DC path to the control grid is open (like an open in the RF coil or bandswitch). What resistance do you measure from the grid cap to ground?

(Since there's no AVC bus, the coil ties directly to ground according to the schematic.)