My NAD 7020 SN:A7224061 with updated PCB = NOT schematic as in most Internet .pdf files, only:
rev2 NAD 7020 service manual, starting at serial number 7218469: NAD 7020 SM
has no FM Mute output, no stereo light, no centre green tuning light. The FM, AM, AUX, Phono still work OK but the unit now gets warm near the power transistors & smells to the right of them. When opened up found -33V on the top of C537, still -27V after turned unit off for 5 hours! Definite burning/chemical smell & heat forward of the 4 power capacitors 2200µf each.
Looking under the main PCB found burn marks around D905, measured R = shorted!! D905 does not show up in parts list, & was hard to find on schematic = grounds a centre tap directly on the transformer.
My question is: what other parts are likely destroyed as well? Or the whole FM MPX circuitry?
Any help would save me a lot of time & grief.