A user on the Arcade Controls Forums noted that Joust and other similar hardware Williams games had a strange behaviour.

When you would put a coin into slot one (5) it would register one credit. When you would put it into the left slot (6) it would register *four* credits.

Did some looking, turns out the driver is almost correct. It has the third coin slot in as the service button (the service menu is accessed by hitting [F2])

So I worked on it a bit. Couldn’t figure out what it was doing, as I didn’t realize that the proper button had already been entered, it was just labeled wrong.

Carlos Santillan filled me in on what was happening, so I rearranged things a bit. Now, hitting:

5 (left slot) gives you one credit
6 (right slot) gives you one credit
7 (center slot) gives you four credits.

I could have done it left-center-right, but I thought that would break more than just a few cabinets. But if someone wants to hook up their Williams cabinet to one of these style coin doors (mainly Defender cabinets, I believe) they can.

Likely it was done before with doubling up on the left slot, but now at least it’s accurate.

Available here. Put into your ./src/drivers/ directory and compile as normal.