Quattro Pete
Thread starter
Originally Posted by dirtymudder
here is a block diagram of the amp.
amp diagram
The output uses a STK package output STK-433
These used to be notorious for shorting out. What happens is when they short out, straight power supply voltage goes to the speakers. when that happens a protection relay kicks out to keep the output from getting to the speakers.You can see the speaker relay in the block diagram you will have to get your volt meter on the line before the relay if there is any voltage there the STK package is shorted and keeping the relay from kicking in.