First off, try and post this in the Ion thread from now on ok?
And second, what may be happening is something that a lot of people used to have problems with, we had a lot of these questions back when the Ion first came out.
Usually the problem was that the membrane button pad would be getting stuck down and was continuing to push the switch after you turn on the gun, so it would turn on and then about 3 seconds later it would turn off again as if you never let go of the button because the button is still pushing the switch. Does that make sense? i hope it was clear enough lol, i would say try kinda breaking in your membrane button, or just buy a virtue ion button and it might solve your problem.
Here is a test you can do. Pull your board out of the gun and then plug the battery in. Turn on your gun using the switch that is on the board (it should be the top gray switch) and see if it turns off again by itself. If it does, then it is a board/switch problem. If it doesn't then you know it is the membrane button on the frame that is the problem and you need to either break it in or buy a new membrane button (virtues work really well, thats why i mentioned that one earlier)
Hope that helped, if not... well... someone else in here can lol good luck
