Why is there no sound on the mat. motherboard ASUS M5A97 R2.0?

Question

ASUS

Good and bright day!
A couple of years ago, I built myself a typewriter on my mother ASUS M5A97 R2.0. I am not a specialist, not a pro in these matters, but I can do it according to the instructions. So, everything started, earned, except for the sound. Because not a specialist, then what was the reason, I could not figure it out, put a USB card and listened from it. But this crutch has already pretty much got me ...
The whole system shows that the sound is coming, it does not show any errors, the front panel is connected, but there is no sound anywhere - neither in front nor behind. Device from AMD turned off.
What to do and how to fix it?