I've actually got one of these DVD/VCR combo machines, mine's a LG V782W but looks almost the same from the outside. I struggle to see any difference at all in the internals, exact same PCBs, not fitted components, and everything else. It was even a dumpster dive like Dave's one.
Anyway the none of it worked, I've found any fixed two problems:
1. VHS section didn't want to take tapes, was simply misaligned somehow, seemed to almost fix itself.
2. The DVD section would make horrible noises when trying to play discs, and the open/close button only worked for opening the drawer. Tracked to to a funny microswitch with a lever arm in the middle of the mechanism in plain sight. Switch was OC and not very springy, fixed by unsoldering it, which magically fixed the contract problem
. Prying up the two ends released the top cover of the switch, and letting the contract out and then sticking it back in fixed the springyness.
Only thing now is it still wont play DVDs, it scans the disc, then gives up and spits it out. I think the laser is operating, which just leaves the read mechanism. Anyone have ideas on how to troubleshoot that part ?