Unless these things are overtightened (and smashing the O-ring) duct tape will work. No clue what will be involved in fixing it though. Each problem is unique. But whenever I have to crack open casebacks to debug a problem, I stop debugging as soon as the solution is non-obvious.
One time I had a 2836 just seize up on me and the winding stem wouldn't budge. I cracked open the case and saw that a screw had come out and lodged itself between two moving parts. It was a simple task to extract the screw with tweezers and put it back in place. But, like I say, if it hadn't been an obvious fix, then off to The Zigmeister it would have gone.