Garage door opener repair

A while back, our garage door opener (a Genie Pro 82 screw-drive) developed an odd problem: the light was stuck on. Normally, it is supposed to turn off a few minutes after use, but now it stopped turning off.

I reasoned that it was probably a relay that failed (it's always the moving parts that fail) and that it was stuck in the closed (i.e. "on") position. A quick search online confirmed that this is a common failure mode.

The opened opener:

Man, talk about old school! A one-sided circuit board, all through-hole components:

Those black plastic boxes are the relays. The one on the left controls the light. After desoldering the relay, it was actually quite easy to take the mechanism out of the housing:

At this point, the relay had unstuck itself, and the motion seemed pretty smooth. However, there was residue on the contacts (probably due to electrical arcing) that could have been causing the problem. I used some sandpaper to clean up the contacts, and decided to give it a try.

My lovely assistant soldering the relay back onto the board:

And it worked! It's been a few weeks now and it's been running fine. I was pretty happy that we were able to solve this using just a bit of sandpaper. I was expecting to replace a relay, possibly a circuit board, maybe even the entire opener (because replacement boards for this 20+ year old garage door opener seem to be hard to find).