I took it out of my pocket and tried to turn it on, hmm, twist switch was rather tight. Tightened it down or maybe it was already down. It didn’t turn on but I figured I maybe had left it on all night by accident and drained the battery. Started to remove the head and heard a popping sound. Battery (alkaleak but fairly new) had some kind of black stuff on the casing near the negative terminal, no other obvious damage to the light or battery. I put in a new battery => won’t turn on. So I guess the circuit is blown.
I like the light and they are affordable so I guess I’ll get another, but it seems like a shame that I don’t see much of a way to repair it or scrounge usable parts from it. I will try to remove the circuit board when I get a chance. Not now though.
Oh well. Bring a spare.
I got around to looking and there did seem to be a little bit of crap on the spring. I sprayed contact cleaner on it and rubbed it a bit with the battery terminal, no change. I’ll mess with it some more when I get a chance. Probably not tomorrow since it’s a big US holiday and we’ll have visitors and stuff.