Yeah usually the rubber grommet that is around the positive pin is probably a bit messed up if you have some vodka or preferaby everyclear you can use that to clean it... what I would suggest is to take all the tubes off the spring off the bottom etc and clean it all dude with rubbing alcohol then let it sit for a hour then for the rubber grommet take a small small screw driver, paper ckip etc and go all around the middle positive pin on the 510 connector and see if any grime etc comes up try to get all that stuff out if you do this and it still does not work sometimes with the Vamo's with alot of use the positive wire starts shorting and its a pain to fix.. I hope that is not the case hope that helps....are you using one 18650 or two 18350's?