Might serve to find out where it had chaffed and stick a couple of layers of tape over it to protect it.

The red wire IIRC is the 'unit ready' line. A 'low' signal (i.e. the line is 'off') indicates the unit is at the ready state. I don't know how this affects tray locking on CD drives, however. I'd probably put a bet on that the wire was grounding to the chassis and staying 'high' (i.e. 'not ready') which was locking the drive as the computer was probably polling it.