I bought brand-new UD-3900.
The Power Led is flickering (Blue led) and it’s not working with my laptop.
I also Put UD-3900 USB cable to another PC, but it also not working.
It seems PCs cannot sense UD-3900 because there’re no beeps and no detection when I put the USB cable into my PCs.
I used UG39DH1 before, I sure I followed your instruction well.