[Paul Babiak]

I have a client with an ADAT-XT that has the analog inputs stuck in
2-bus mode - that is, channel 1's analog input is also routed to
channels 3, 5 and 7, channel 2's analog input is also routed to channels
4, 6 and 8.

Any input to channel 3 also shows up on channels 5 and 7, input to 5
also shows up on 7, the even numbered channels behave similarly.

Hitting the proper bus-mode select switches for 4-bus and 8-bus modes
lights up the appropriate LEDs, but the audio routing doesn't actually
change.

Have performed the factory power-up re-initialization numerous times, no
help.

From the schematics, it appears that all this is controlled by one large
chip on the main processor board.

I've done the obligatory googling, nothing about this has turned up.
Is this a known/common problem with a relatively simple fix, or is the
repair likely to cost more than a replacement unit is worth? Thanks.