hi
I have this problem, too.
But i think i know something.
I have a MR-J2S-40A amplifier. And my socket has 6 pin. P - C - D - L11 - L21 - N.
My jack is 5 pin. And i pushed wrong area. I made a short circuit...
I hope i can find the bad part of my amplifier.

Do somebody have a wiring diagram for the ampifier?
Great help for me...

thx
borcz