Lost channel dx with U-Mix 44

Hi
I have a problem with the U-44 mix, I lost the right channel of the deck 1.
The channels come out of the PC all is two-and even reversing the cables, the missing channel is always the right, the card is broken???
I have a problem with the U-44 mix, I lost the right channel of the deck 1.
The channels come out of the PC all is two-and even reversing the cables, the missing channel is always the right, the card is broken???