Just picked up Realistic STA-2290 that has an issue with the tuner/display section. Suspect its a power supply issue since according to the block diagram in the user manual, it's separate from the power supply for the amp and preamp, which both work fine (tested with CD player through Aux input). The power meters also work, just the tuner display (and tuner), source and FM Stereo indicators are out.
A schematic or service manual would be great, but any advice would also be more than welcome. Thank you in advance for any direction you can provide!