Go Video dual deck VCR - no audio on copied tape
 

I just picked up a used Go Video DDV 9000 - a dual deck VCR. Everything
works great EXCEPT when I copy a tape from deck 1 to deck 2 there is no
sound on the newly copied tape. The original tape (the one copied from)
sounds fine on Decks 1 and 2. Does any one know how I can fix this? Can
I make an adjustment through the Menu. If not, any thoughts on how much
the repair will be? Thanks.