I installed LEDs, some colored, and used 750 Ohm resistors on the controlled lamps. It worked like a charm.
Kids love this game and it is doing well on route.
Yes, the 555 lamps are hard to get out and hard to get in - PITA as you say.
I would suggest that you take a look at this LED PAC-Maze board to replace the original:
There are 5x5 positions on the Pac-Maze board. Each position has two incandescent lamps, one with a red condom and one with a yellow condom. That’s 50 lamps. At one buck plus each, you can begin to see the value of the Geeteoh LED board. And you won’t have to worry about those pesky condoms or replacing burned out incandescent lamps ever again.
I replaced the Bally flippers with Williams, kept the originals for the purists, and it greatly improved the speed, accuracy and fun of the game.
I wasn’t that impressed with the game play when I first got it. But with the mods I did and after learning how to work the Pac-Maze, this has become a keeper.