@hasmarto Perhaps/hopefully all that has failed are the two internal fuses on the affected channel. I see the following statement in the manual:
Beyond that possibility, I'm not sure.
Good luck. Regards,
-- Al
Two internal fuses are mounted on each of the two amplifier circuit boards. These fuses have two green LED’s associated with them. Both LED’s should be lit when unit is ON and operating properly. Failure of either of these LED’s to light indicates that the corresponding fuse is open.
Beyond that possibility, I'm not sure.
Good luck. Regards,
-- Al