Yamaha Psr 8000 Auto Accompaniment

I had the same problem with my PSR-8000 but finally figured it out.  While playing with the accompanyment, check to see if the chord showing on the display matches the chord you are actually playing.  I had a malfunction first with my "C" key and later the "F#" key on the lower end of the keyboard, down where the chords are played.  So when I was playing a "C" chord -- with the "G", "C" and "E" keys/notes -- the keyboard only picked up the "G" and "E" keys/notes -- and played the accompanyment to match an "Em" chord, instead of the "C" chord.  It was very frustrating.  Initially I could hit the chord again and the accompanyment would switch and play the correct chord.  But the problem got worse the longer the keyboard was turned on.  Something to do with they keyboard warming up made the problem worse.

I never had this issue corrected.  I did take it in two times and still the problem persisted.  I had a similar problem with one of the keys/notes on my PSR-2000 keyboard not being recognized when it was played.  I was only charged $85 (US) for the fix.  So I imagine I could take the PSR-8000 in to the new repair facility I use and the fix wouldn't break me. 

I hope this helps to explain your problem.  I had a hard time trying to explain myself in this post, so I hope this made sense to you!  If this isn't your problem (again, check the display against the chord you are actually playing), I don't know what else it could be.

-Kaylbe