Generally, we don't mess with the plug pin as you call it. When you get a bunk carto that is new out of the box, the best procedure is as follows. Step 1. If you're getting weak or no vapor on a new carto and you know it's full of juice it generally means that the filler is not seated at the bottom of the carto shell. In many cases pushing the filler down gently with a large McDonalds straw will solve the problem and the carto will work fine from that point on. If the carto isn't firing at all, then change batteries and see if it fires then. If it doesn't, then and only then you may need to raise the center post on the cartomizer just very slightly so it makes good contact on the battery center post. If after this procedure it still doesn't work then you may want to take it apart and trouble shoot it. Using the detailed instructions I have provided in this thread, remove the filler. Do not remove the center tube. Clean the inside of the blank carto and then dry burn the coil. After 5-7 dry burns you should see the coil glow cherry red. This tells you that the carto and coil are good. The only reasons for the carto not working is the filler or the connection to the battery. Reinsert filler and refill as per the detailed instructions and you should be good to go.