Take the glass off and manually move the flippers. Do they move smoothly with no resistance.
start a game without hitting the flippers. Manually move the flippers to their up position with your hand.
Does the flipper stay up and resist being pulled back down?
If the flipper stays up the hold winding in the coil is energized when it shouldn’t be which is either a short to ground or a board issue.
Another possibility is your flipper switch optos. Go to the test menu, switch levels and take a picture and post it here