Hi, I know there's a guy with a similar issue to me in another topic, which I've replied to, but I thought I'd post something myself in case someone can give me an answer more directly/quickly.
The first time I tried using it I had a bass guitar plugged directly in and was getting some levels in Logic ready to record, all was working fine, I was getting sound and levels on the front of the device. But, for seemingly no reason, the device randomly froze up, the VUs stopped moving and the sound cut out. Not only that but pressing the power button did nothing, it remained lit up. I even left it like that for a while to see if it might sort itself out but nothing. Finally, I just had to switch off the main power at the wall and then it turned off.
I'm nowhere near a service centre, unfortunately, so if anyone's got any advice or maybe encountered this problem before and fixed it and could help, I'd be hugely grateful!!