Bally fuse holders are notorious for going bad.

Are your score reels at all 0’s? That may be keeping the scoring motor running. If the pinball can’t get through the reset cycle it won’t start a game.

Do you have the manual for the game? It will tell you what the reset cycle steps are.

Alberto

Go to page D of the manual. It covers the correct settings for the score reel switches. If one of those is not in the correct state, the game will continue trying to reset them.

Start by checking the status of the score reel switches per the manual. The stack of three switches on each reel change states as the score reel moves, letting the game logic know what the status of the reels is.

There are three states, “0”, “9”, and everything else.

Use a multimeter to check the status of those three switches during each state.

Alberto

Don’t trust your eyes to check if a switch is open or closed, always go with a multimeter and measure the resistance.

The humming is probably the lock relay. They tend to do that.