Sydney
I mostly work on old WMS solid state machines, sys 3 to 7 and these are pretty useful.
The pen has two leds back to back in parallel, useful for probing cpu and driver board logic level. The led bar graph is used for;
solenoid outputs: plug onto driver board 2J9, 2J11 or 2J12 clip lead to 5V +ve on board - used to test driver board out
spec sol inputs: plug onto 2P13 with gender changer, clip lead to 5V +ve on board - used to test pf switch inputs
switch col drive: plug onto 2J2, clip lead to +ve on board - used to test switch col outputs
switch row returns: plug onto 2P3 with gender changer, clip lead to +ve on board and can test pf switch row returns
You can find out a fair bit with just these simple bits built for a few $.
