Check for broken plastics - the blue and yellow one under the left ramp is often cracked and hard to find a replacement for. Also check to see if the ball auto-launcher is working well. If you can open the coin door, you can go into Diagnostic Mode and use the Easy Trough Clear to repeatedly eject balls and see if they always clear to the upper left flipper. Play a few games to make sure the ball trough is reliably detecting all 6 balls and not ejecting multiple balls (this happened on mine). If you get the game and have any questions, send me a PM any time.