I don’t know anything about electronics or how to fix them? But! This problem sounds exactly like what’s wrong with my kr 9600 and I know what caused it was about seven years ago one of my employees moved by KR 9600 while it was on and playing pulled out one of the speaker wires and accidentally crossed it.
And shut down the whole sound system completely and I have never tried to fix it so that’s why I looked at this problem tonight but when he crossed my speaker wires it killed the system so now I know how it happened I don’t know how to fix it. Thanks Keven