I acquired a used ikelite substrobe MS and it is in need of repairs. It worked great last week, but now fails to fire in the slave mode. It has a rattle inside, like a loose nut or screw. One of the screws holding the battery leads is loose and not able to tighten. I think the backing nut is off. I was going to see if the stobe light unscrews from the housing. I only get about a 10 deg. turn and it stops when trying to unscrew the housing from the strobe light. Has anyone serviced their own ikelite strobe?