Hi,



I am trying to fix RCA STAV 4090 amplifier that is a clone of Pioneer
VSX-D710. It is 5 channels unit that is using Pioneer's PAC011A and PAC010A
integrated amplifiers.



When I got it, it had a blown fuse in the ground rail of power supply chain
and filter capacitors in +VL and +VH rails were fried and leaked. After
replacing capacitors and fuse, amplifier has +12 V offset on the power
supply ground, amplifiers output is 0V.



When I am connecting speakers it works, but starts to overheat -- DC current
protection seems to be blown. Also there is a strong 60-120Hz noise in all
of the channels.



The question is: how split rail supply ground is controlled? It is not
connected with the signal ground as in other schemas that I saw.



There is a part of the scheme that controls some "NECK" voltage that goes to
integrated amplifiers. It was contaminated with the acid from leaky
capacitor. Does it have anything to do with that? What this "NECK" stands
for?



Thanks,

Anatoly