OK, so, I got a lovely Purple Auto Diamond (short) about a week ago. I've used it twice and then last night, no matter WHICH cartridge I tried it with, it wouldn't "go". No light, no vapor, nothing. When I put it on the charger, it registers, blinks, then shows the charge is "full", and I can draw through it fine (so the vents aren't blocked) but it's not "firing"... I had this happen with an ashcap battery before (actually *it* NEVER lit) but now that I'm more 'tech savvy' with the batts and carts, I've debugged the steps but nothing changes the result. Any ideas? send it back for exchange?