Anyone had the controller just go wonky on these? I

Ive had it lock up, lots of wierd characters.
Ive had a couple times , machine just starts going in a random direction.
Even had it tell me Z axis over travel when the spindle is ~2" down. Then when I hit reset, the x, y axis jump. Real nice to drill bits when theyre in the part!

Glad this is a back-up machine now. But any guesses? Bad connection somewhere, something on its way out? Id like it to be more that a 6500# paperweight used very occasionally.