Video sync

I was wondering if there was a fix for the video sink problem I am having, I have this video that I am playing on both of our DL2's & it is never in sync, I have spent tons of time on trying to correct this but eventually found no solution, basically they are programmed to start on the same cue & when it comes up one DL2 is money, but the other always seems to have a start delay? I'll try anything please help.