For the last year I had the power supplied via the USB cable in the USB/AV as stated in the manual. Recently I noticed the K1 wasn't working right. It would start and stop recording over and over. When troubleshooting I noticed that once I plugged in the power the screen died and the problem appeared. If I tested the unit with only battery power it worked fine until the usb power was applied. Today I decided to try and plug the USB power into the USB port used to connect to a pC and it works fine. Is this normal or has anyone else have the same issue.