ORIGINAL: kd7oir
I had the same prob. with a servo and found out after I opened it up, a solder joint had come lose inside. Resoldered it and it is as good as new. I was ready to buy a new $100.+ servo till then. I always open up an electric part after determining it's bad because I've already decided I need a new one and this one is bad, so I cant screw it up any worse. 9 out of 10 times it's just something simple like a bad wire or solder joint and I've saved a ton of money. With the motor vibration and punishment we put these through, it happens alot.
You have the right attitude, but the ratio is more like 1 out of 10. Most electronic damage is done internally and unrepairable.
I think you might have teh right idea cord arrow, when that motor is WOT it's causing a vibration the other xtals didn't like. Happy bashing!!