one of the LEDs on the PIN2DMD board will flash when the PIN2DMD is recieving data from the pinball machine. Do you know which version of PIN2DMD board you have? there is a method to test if the input (from the pinball machine) is good see https://pin2dmd.com/ at item 3.

Based on the other post about the similar issue, try setting your PIN2DMD to default and saving and then back to Data East mode. or just check the setting for Enhancer in the PIN2DMD menu, it should be ON.

You have got the expected result: pin 9 is not used.

from the PIN2DMD site:
It displays which of the input pins 1,3,5,7,11 (and 13 for Nucleo and EVO boards) is connected to ground.

@action76, one of the LEDs on the PIN2DMD board will flash when the PIN2DMD is recieving data from the pinball machine. do you see a flashing LED when the PIN2DMD is connected to the Pinball machine ribbon cable?

I test all of mine - does the controller and display work, I would never have thought the inputs could be broken in this way. It wouldn't be too hard to make up a little test box that plugs into the ribbon cable plug and test the inputs using the built in test mode.