I can't get my Guru to work when it is plugged in to A/C power. It cycles on and off constantly. I tried 3 different power adapters. It will work fine if it is plugged in to the cigarette lighter output of my battery pack. Has anyone run into this problem before. This has actually been going on for a while, but I'm just now getting around to asking about it since I have a workaround and of course I waited so long that I am probably out of warranty.