Help!!! Sonic Frontiers Power 2 - buzzzzzzz

[Pdspecl]

Hello,
I have a Power 2 amp. I started getting a low level buzzing from the left channel speaker and contacted Chris Johnson - Part Connexion. The buzzing (with his advice) was isolated to be coming from the input selector switch - Mute, (-). (+). XLR. The amp is set up to run XLR or single ended. I use the single end set up. Per Chris sometimes - feedback occurs when the switch does not work correctly. Using the part # Chris provided I ordered 2 switches from Digikey.com. I removed all the screws from the back plate (holding all the input/ouput connectors). Problem is I can only pull the cover back about 3/4 of an inch. Some of the wires MAY be short and not allowing cover to slide back more. I may flip the amp over and remove the bottom cover to get a better look. Anyone have any experience working on this amp? Any suggestions?

Note, I was very impressed with Chris's support and tolerance for emails, questions..... Very nice guy.
Thanks,
Paul