I'm backing up the 'check the motor connectors' suggestion. Often they are semi-loose fitting and can pop off the terminal while playing or even just transporting (or shipping). If you find one off, take some pliers and give the connector a gentle little squeeze, then put back on the motor making sure there is a bit of resistance. Then arrange the wires so the grip plate goes back on without jamming them, reinstall and try it out.

I'd put my money on the battery. Its quite possible that the motor connectors popped off, but I sure haven't heard of many cases of that happening..

A half dozen times from my experience, once iwth my own gun. Easy fix. One classic one I recall was Primus, halfway through the day he had to switch to a pistol for an hour because he knew his connector popped off and no one had a multitool with a screwdriver to take the grip off to get him going again. He fixed it back in the staging area later. It even happens often when putting the grip plate back on, is mostly what I've seen in the years I was a gun tech. Bit of a pinch with pliers keeps it from happening.

haha good to know....

I'll be bringing a multi-tool kit in my MAP backpack this summer then... :P