lately my receiver (Integra DTR7.1 - same as onkyo 787, i think) has been kicking off in protection mode whenever i play something semi-loud like action movies. i can start it right back up but have to keep the volume turned down. i am running only the center channel with the receiver, with no rear speaks connected, and using preouts to an amp for left and right. i have a powered sub out of the receiver's sub out jack. it is running 5.1 setup (even tho there is really only the center being driven by the receiver). the volume is not excessively loud; what could cause an overload or whatever to trip the protection at normal movie listening levels? i assume the rear channel amps are on, but no speakers being driven. is that the reason? manual doesn't cover this.. thx!

any other onkyo owners with a 787 model had this problem?