I will doubly recommend the advice to remove any loose debris from inside the cabinet prior to transporting it on its back. Or at the very least, triple-check everything inside the cabinet before powering it up after you unload it.
Learn from my mishap... I brought home a cabinet (transported lying down) and when I stood it up, I opened it up to check for loose parts, brackets, nuts, etc to make sure none had lodged themselves anywhere. Well, I missed something. There was a small washer, probably a 3/16" one used on a joystick bolt or something, that had wedged itself between two lugs on the transformer. It wasn't there before I brought it home because I had been playing the game before I loaded it up.
Anyway, when I powered up the cab, no game! Everything else worked (monitor, marquee, coin door), just no game. Turns out the short caused by the washer blew the fuse for the supply to the power board +5V for the game boards. Naturally the transformer fuse was some oddball that I couldn't find anywhere locally (I never over-fuse!!), so I had to order one and a couple spares from mouser.com and wait a few days to power up the game again.
If you lay down games to move them, check very carefully for strange things like this. They do happen... Here's where the tiny washer was wedged:
