hifi engine

Onkyo m-5000 Protection circuit

Hello all i'm hoping i can get a little help here!.First off let me say i'm still very ''green'' in the world of hifi repairs.I picked up an Onkyo m-5000 power amp for 10$ do to the fact the protection circuit was activated,i thought this would be a great first project for me.Well it is becoming a little tougher than i thought because when i google onkyo amp protection or whatever i keep getting result's about receiver's not amplifier's.So with this being said could someone point me in the right direction to reset this protection circuit.Thank you,