Help - amp going into safe mode

Hey! my friend's harman kardon ss amp keeps going into safe mode and stereo exchange in nyc (where he bought it from 4 years ago for $700) wants a minimum credit card authorization of $380 just to look at it! what a scam. he's moved it around to different outlets in the house but it keeps going into safe mode every 5 seconds when turned on.

anybody have ideas for him?

thanks in advance.