I bought a used TE GP12 SMX Premap a couple of weeks ago. I haven't even had the thing on more that a couple of hours since I got it and today i was just getting going, had it on for less than 5 minutes and it shut off. Now it does nothing, it's like it's not even plugged in. Checked the fuse in the back and it seems good. Are there anymore fuses inside? Any common problems like this? Super annoying.