new to the forum here, but i have an epic design studios smpl v2 mod with a Derringer clone rda. i wouldve gotten authentic but i wasnt ready to fork out that much cash right off the bat... anyways i have 25r's in it and for some reason there is black ring that appears around the top of the mod near the rda. at first it would just have glowing embers when the button was engaged, but with a file i could easily make it go away without any problems. well now it will spark and even stop working. to get it to work i have to file the black ring a bit and it will fire right up like nothing is wrong. i did have a problem with my rda where i was running a 4 strand parallel build and it got so hot that it melted a plastic stopper that held the center post in place. Being the handy man i am i fit it back in place with a two part epoxy putty knowing it is not conductive and will insulate the center post as the plastic stopper did. what is causing my mod to have a black ring and spark and stop working? its so strange because everything is making a good connection and the 510 pin is pretruding more than when i orignally got the rda for safety purposes since it is a hybrid mod. any ideas ??