Recently, I bought a used Dremel on flea-bay, and after few uses, it simply stopped. Crap! So I disassembled to see what I could see. I'll cut to the chase, instead of a faulty switch, or the usual suspects, the trouble was a broken connection at the field winding. The fix was to unwrap one half turn of the winding, and reconnect at the post. I am sharing this because by using a meter and a little patience, it may be well worth your time to investigate one of the few tools left that you can still work on if it fails. Finally, good news for my troubled brain.