Harman Kardon amp displays "PROTECTION"

[BCorson]

Harman Kardon amp displays "PROTECTION" when function buttons are selected. It appears to power up (lights up) you can hear a relay click then the word "Protection" is displayed in main window. After this it will not respond, have to turn off and on again. I would like to know what parts to look for to fix this. Amp has many what look to be Transistors, but I think they are pre amps. Most use two big ICs. Any help would be most appreciated. Thanks, Brad