Hi, I have exactly the same problem,
I just received the 5102p today, brand new, when I unboxed it, I found that the knobs are not working, because I'm in a country where I can not do a return,
I just replaced the faulty knob and it's was working.
The problem I got is I was working with it until it got stuck. and the screen goes black, when I restarted it, I see all the lights turned on but no screen, I suspect the firmware got corrupted, I have no idea how to restaure it or use the reset via USB without the screen.
Any advice would me much appreciated, just lost 250$ for a brand new and waited too long to receive it. :'(