NG500 McCapsule problem

I few months ago I built a McCapsule with an ng500, and as soon as I put it into my Micra I noticed a flickering. After talking to several people here on CPF, I determined that it was a contact problem, so I sanded all the contacts very lightly with 800 grit paper in the whole flashlight to get a clean connection. This seamed to work for quite sometime. Then last weekend we went camping and the light will sometimes get dim then turn off, if I give the head a little tap it comes back on. I can't make it turn off, it just doesn't it randomly. I've noticed that the pushbutton tail cap has to be screwed on really tight in order to work properly. Does anyone have any advice? Anyone know of better way to clean the contacts?

Ah I solved this one as well. As it turned out, I had a bad 123 cell in the flashlight all along. I had thrown out the Micra cell as soon as I got it because it was ruptured. The only 123 I had lying around at the time was the one that was included in my Q-III, so I put that in my Micra. When I got home from work, I tested the 123, and the volt meter said 3.16V, but when I put a load on the cell, it dropped to 2.5V. I am guessing that it was just a bad cell, so I popped a SF123 in it and it is working fine. Anyone else have a similar problem? Oh, btw the cell supplied with the Q-III was a Panasonic (as if you didn't already know).

Wrong forum to continue this thread in. Moved to Custom and Modified.