Al,
Maybe I misread the initial post, but I understood it to sound like this:
The keyboard was purshaced and claimed in one tax year. Then it was sold in a subsequent tax year. Wasn't that the case? In that scenario, don't you simply report the $700 as income recieved in the new tax year. You can't adjust last years depreiciation, can you?
(This is why I pay someone to do mine - too complicated)