Krell FPB-250M Help

I recently swapped cables in my system but when turning my amps back on discovered one of them is now not working properly. The amp will switch out of standby mode to play mode temporarily (one blue LED light to three, for those who know Krell) but then switch back to standby mode. I spoke to Patrick at Krell and he says the amp will need to be serviced.

Has anyone had experience with this, and can help clarify what may have happened? And if there's a possible solution that doesn't require a trip to CT.