[BC] Denon DN-C680 Cd player error 400 - assistance

[Reader]

Hello all,

We replaced our C680s at  the beginning of last semester with some 
cheap DJ-model Numarks, which are already going downhill, I'd like to 
get the Denons back online ASAP.  When I turn them on and insert a 
CD, I get "ERROR 400" on the screen.  I've emailed a few service 
centers and gotten nothing back at all.  Anybody know what the cause 
is or how much I can expect repairs to be?


Thanks,
Rick Heil
(Incoming) Operations Director
WONY, 90.9FM