I agree, we checked all of that, and I had it narrowed down to the channel on pins 16/23 on the power amp. However, there still seems to be some randomness to when it will trip or not trip, and I do not feel confident that if I set up a set of conditions and see what happens, that it is repeatable. More than once I have set up the same conditions. One time protection trips, another it does not. I'm also puzzled by the fact that it will only trip once the entire time the amp is on, no matter how long it is on. Also, if the amp has been sitting off for hours, then is turned on, protection will trip sometime in the first 15 minutes. I can turn the amp off and then on again, even waiting half an hour, and protection will not trip. I have concluded this is because the temperature of the components has increased, and have not cooled off yet, which does point to the fault being temperature dependent. I've wondered if I place the amp in a warm room will the circuit trip at all? I happen to have it in a room that never gets above 70 F.
As I mentioned, I can try the scope on the resistors, but if I don't find anything, I'm at a loss and assume I'll have to live with this issue.