Right away my first thought was that lifting the playfield put tension on the wiring harness, which maybe cause a short somewhere. Like johnwartjr said, you'll have to investigate getting the +5VDC back first. I would suggest that you also try to carefully try lifting the playfield with the backbox innards visible so you can see what might be pulling on what. It really seems like something happened during what you did, rather than coincidence.

Well, at least you looked...could be coincidental. Vibration alone from lifting the playfield could have jostled something. Take care of getting the power supply running, then search again as thoroughly as possible again. That's really all you can do. If something is loose or shorting it might rear its ugly head later.