Drunken person fell on my guitar, (Yamaha BB3000), at a gig. I now have a wobbly volume pot and damaged knob. I haven't had so much as a crackle from this in 23 years and would like to replace with the same, (rather than some cheap rubbish). Yamaha don't seem to be much help. I have been trying to replace the 'C' spanner, (for tightening/locking the machine heads), that came with the guitar for some years now. Any ideas?