Mike wrote:
I have an old Craftsman chain-drive garage door opener. It was there
when I bought the house, it's gotta be at least 20 years old, but it
works well (noisy as all get out). Anyhow, there are light bulb
sockets on both sides of it. The light bulbs are supposed to come on
when the door is being opened or closed. They used to work. Now,
they come on for a couple seconds, then go off, then flicker a bit,
then come on, then go out, etc. I jiggled the bulbs in the sockets a
bit and they stayed on for a while, but then resume the erratic
performance. One might guess that the bulbs might be coming loose in
the socket from the movement of the garage door, but that is not the
case. The bulbs remain snugly in the socket. In fact, they work a
little better (i.e. stay on a little longer before starting the off-on
stuff) if I unscrew them slightly.

If both bulbs are going on/off at the same time, it's doubtful both sockets
went bad at the same time.

I have a similar opener, Craftsman chain drive, probably from the mid 70's.

My developed similar symptoms, no lights but in my case it was the driver
relay for the lamps, is on the main card when you slip the case off. The
contacts were burned/pitted. Think the main tip-off was if you knuckle
rapped the housing, they came on.

It's one of the older types, (like an Omron), if you are careful you can
pull off the clear plastic top (usually two tits on either side clamping it
in place), sand the contacts a bit and it'll be good as new.

Think I did mine 10 years ago now and is still fine.

-bruce