A call to Outlaw tomorrow could probably shed some light on the issue, but I'd start by unhooking all the speaker cables from the amp, flipping the main power switch off and back on, and trying to turn it back on. According to the manual, it should come back on once the problem condition is removed. If it does, you can shut it back off and start adding speaker connections one at a time (hook up one speaker, turn amp on, turn amp off, hook up next speaker) - if there is a problem with a cable, you'll know which by the cable that causes the amp to go back into protection mode.