I don't know if you are a Mac guy, or have a mac guy working on it for you, but I worked on Macs for three years and have always had success getting them going with minimal work. If you need some help, I'd be glad to offer what little I know.
If it is a 2010 or later Mac, the built-in solutions for repairing have always worked for us (we had about one hundred of them). Every week or o we would have one or two blow up, and it was generally a malfunction in the SMC, and when it wasn't that (rarely) a reinstall (format) always solved it. You can find the specific directions for your model to reset the SMC if you haven't tried that on Apple's site,
here
. It takes about 30 seconds to give it a shot. The PRAM gets crazy sometimes too, and
here's
how to reset it.
