2010 Protection Mode

A friend of mine has had a 2010 sitting around for ages because it is stuck in protection mode. I was wondering if anyone can help me sort through some voltages to find the problem? It looks like someone tried to make a repair to the main amp boards at some point (the electrical tape gave it away) and I thought about disconnecting the amp boards. If I do, should it come out from protection mode if the issue is in one of those boards?

Thanks!

Check your mid point voltage (offset)per page 11 of the service manual.

http://www.hifiengine.com/manual_library/yamaha/ca-2010.shtml

May save you from having to pull the boards.

If you measure less than 1 volt it will probably adjust down close to zero. And your problem is not on that board. If you have more than a volt, it will probably be alot more and will not adjust. Bingo you have found the problem board/assembly. If both boards dc offset(midpoint) look good. Then the problem is in the power supply or protect circuit.