Rayfoss waterproof red issues

I got home yesterday and turned on my red laser, and it didnt go on. Last i checked, the battery was 4V. So I open the laser, battery said 3.9V. So I kept trying to turn it on, and it would flash bright, then dim, then off. I've seen this one, when my battery was below 3V. So I checked it again, 3.9V.

So, thinking my laser is dead, I put a 3V wall power suplly to it, and the laser was full power 200mW solid. 3V. I put the battery back in (reading 3.9V) nothing.

Why does my 3V PSU power my laser fine, but my odd-brand CR123A wont work? Could it be the cheap quality of the battery and its dieing?

EDIT. I just figured it out...I did foil on the battery as a cap, laser went on. My cap is acting bad...

EDIT 2.


Ok, I guess this thread is now a "In case this happens to you".

I got it working, I removed the plastic disc in the tailcap which presses a brass contact against the tailcap switch contact. I did a short-meter test, and it worked fine. So the brass insulator was making bad contact. After cleaning it (I'm guessing a particle of plastic got under it) I screwed the plastic disc back on, and the laser is now 100% working.

So now you know. If your laser battery works, and the laser doesnt, simple tailcap fix.

Good to know.

Thanks! i was having the same problem...but i got it working by unscrewing the plastic piece, i guess the culprit for making the switch not work just fell out. but thanks for letting us know!

I am having the same issue. How do I fix it? I'm not understanding.

Thanks for letting us know. I might get this laser soon, and its nice to know the fix to a simple but rare problem