Is it possible to strip the internal gears of a tuning machine? One of mine appears to have done just that. I was trying to tune the string and just couldn't get the last 1/2 step for some reason. Then I noticed the pitch was slowly slipping DOWN without me touching the tuning machine...after unstringing that string I found that turning the head no longer moves the string winding peg, and that you can turn the peg by hand. Obviously this renders the machine useless. Is there a way to fix this or do I have to buy a new tuning machine?