Maglite Switch Problem?

I have a 4D maglite that dims shortly after turning it on. I originally had one of Gene's drop-ins in it and thought it was the drop-in at first, but after taking it out and installing the replacemnet bulb from the tailcap and several other LED drop-ins I can see its not (BIG relief). I've tried replacing the batteries with new cells, but get the same result. My question is; could it be something with the switch or is there some other problem? I took the switch apart and everything makes contact as it should. I did notice that the small ring behind the clickie looks like it was originally polished on the outside, but that finish has been roughed up around the outer edges of the rings where it makes contact. Another thing I noticed is the the bulb from the tailcap would light up and would slowly dim until there was no light coming from it at all while all the LED drop-ins would still produce light. I don't know if that means anything though. I'll try and get my hands on some deoxit and see what it does. I'm guessing that's all it is..

Sounds like old batteries, but since you already tried new cells with the same result, I don't know what it could be. If it had a short somewhere, I don't think it would light at all.

If you have a DMM, remove the bulb, turn the light on and see if you are getting as many Volts as you should. While you are at it, check how much resistance there is in the current path (both positive and negative).

If that doesn't tell you anything, try removing the switch and cleaning all contacts. the switch is pretty easy to disassemble and put back together, so clean the insides as well.

Thanks Valolammas! I know there's a DMM lying around here somewhere. I'll see if the local radio shack doesn't have some deoxit. If not, I see fenix store is selling it.