I honestly just use jumper wires and a voltmeter.

Something that plotted multiple switch states as a function of time (like a multi channel o scope) would be useful.. or even something that visualized the state of 5 or so things as lights (simulating the switch test you get in a modern pin) could be useful.

I don’t know if old tone generators would actually work well in an em to trace wires... but that would be useful due to the horrid fading common on most cloth wiring.

Something that easily clipped onto tabs to replace a switch could be useful for troubleshooting... as are your ideas about visualizing or using sound.

I agree. Since you can manually activate any switch or device in the game even with the power off a meter can get you pretty far. Knowing how to use it properly is important though (e.g. measuring pulses, resistance vs. continuity, etc.).

A bulb tester is handy for seeing transient events that happen quickly:

https://pinside.com/pinball/forum/topic/reading-gottlieb-schematics#post-2634425
https://pinside.com/pinball/forum/topic/em-pinball-circuits-basics-to-not-so-basic/page/2#post-3184715

A handy tool would be something to pinpoint where an unwanted short is. A circuit simulator would be helpful too for some elaborate sequential circuits like reset, bonus counts or player unit advances.

/Mark

Flashlight, magnifying glass, reading glasses and a full schematic. Though the problems are electrical, the solutions are all almost always looking for and fixing a broken wire or switch adjustment.

I think the biggest boost is addressing the "I thought it was making contact... but wasn't" scenario. That's why I like the idea of something confirming an effective switch closure

I’ll take one if you find this! Man would that be nice!

Looks like that video is currently set to private.