hk amplifier low level speaker output

[adam]

I have a harman kardon avr 130 amp that has a very distorted and low left surround level speaker output. all other speakers channels are ok, I was wondering if anyone out there can point me in the right direction to get this amp back up and running. I changed the power transistors but still the same?, If any one has a ideas what the problem might be ? or email me.

Thanks in advance,
Adam