"Art" wrote in
:

Look for a DC-DC inverter circuit that has failed. If memory serves me
the DC-DC developed supply voltages both for the tuning and display
circuitry.

Tuning comes right from 5V or 12V. VFD displays would have a DC-DC
convertor, and I don't think they had them back then. It wasn't till
1985/6/7 or so when they went to VFD for their premium stereos, I think.
Before that, they used LED.