One that hasn't been mentioned yet is Fisher. I have an old 1266X and it finally (I thought) took the long dive into oblivion. Sent it in and for a few dollars got essentially a brand new machine. Replaced quite a few of the electronics on the board, new coil (they said it was noisy - guess I had just gotten used to it), rewired the battery connections and a couple of other things. Got the quote back in a couple of days after I sent it and had it fixed and back to me no more than 10 days after I sent it in to get looked at. My thanks to Felix and that group.