I have an area 51 and it's almost done! But for some reason the player A button (the red one) does not work well. Hitting it softly 10 times gives me 1 credit

The thing is.. i do not have a clue how to open the cabinet to get to the control panel! I opened the backside but it there are now screws to get any further!
here is a movie so you can see how it looks, maybe someone had a suggestion?