how do i fix my phillips?

i have a phillips dvd player with six speaker 5.1 system and i believe the internal amp is having issues. it plays a disc fine with no problems but sound is only heard through the left rear(--i think...its been a while--) speaker jack. any of the speakers will plug into any of the jacks they are just color coded. I plugged all af them one at a time into the LR channel and they all work but the sound is really really quiet. is there a way to fix the amp or is this thing trash? I'm good with the hands (auto tech 11yrs) so ive already opened it and dont see anything burnt and no smell bads. If anyone can help I thank you!!