MF Tri Vista 21 channel dead

Hello everyone. I have the Tri Vista 21 DAC and the right channel is dead. I swapped out the IC to the other side to eliminate the other components as being the culprit. The problem switched to the other side. Can someone provide schematics. MF does not list any USA distributors, and I certainly am not shipping overseas.

Any input as to what to look for regarding the lost right channel?

Thanks,

MAK