with the cover off you will note the 2 boards together on 2 heat sinks , there are 3 5 pin connectors 4 black 1 rad wire disconnect 1 at a time and try to power up if it duz the one you disconnected is the bad amp channel , if still shuts down on the other side of the amp closes to front of unit, there is 2 more 5 pin connectors 4 black 1 white wire this time , same as before disconnect one at a time and power up, if it stays on you have found the blown channel. you would then need to remove the board and replace resisters and transistors in that one section.