tevion karaoke dvd player volume problem

Hi i am after the site to download the firmware or a way to flash the dvd player so it fixes this problem.

while watching a dvd or usb or even a aux input after 10 minutes the volume will go down. it never goes
up and d.r.c is turned off but volume still goes down. any ideas how to fix this problem as it is annoying having
to turn volume up every 10 minutes. i was hoping the firmware or software update will fix this but tevion does not
make it easy to find.