All -

Have been reading all I can find on System 1 as am working on my first one now.

Based on the architecture of the board, is there a way to test its operation in situ by applying signal to the input pins (at j1) and seeing the output in the game (as you would manually short the transistors on a bally sol. driver board?

So -

Step 1 - disconnect J1 from MPU
Step 2 - Apply 5V to pin 23
Step 3 - Apply "something" (ground, +5v, etc.) to other input pins on J1
Step 4 - Observe behavior in game (light or coil on)

Basically looking to verify operation of everything on the board all the way to the lamp or coil.

Thanks -

-scott