NAD 7020e receiver just failed most strangely. If only one source is connected to the appropriate input (such as CD),
the signal can be heard on both channels at about 1/2 volume when tape monitor or video is selected. Tuner is also
audible regardless of which input is selected.

I've disassembled it and cleaned contacts etc to no avail. There's no visible damage under illuminated magnifier.

tia in advance for help

Nigel