I do believe I can fix them. Found out how to open them up without damage, and found all the switches. Gonna order a few and fix the one I have laying around. I spliced a good on-off switch into an otherwise good one I just scored out of a salvage truck.

If yet gonna tackle one, watch out for flying springs. Them things are about the size of a 0.7mm pencil lead.

 

Mine work but the paddle for the coast/resume switch is broken. I saved the little spring and bullet for awhile but now I'm not sure where it is.

 

Shhh it happens. Unfortunately the plastic parts are what's not repairable. I've sourced 2 of the switches, and have the genre of the other one. I have to pull it and measure it's dimensions and characteristics to narrow it down.