If it's not working at all you can manually activate the coil by grounding the control pin on the boards to make it fire to determine if it's a wiring issue. I'd do some research before grounding anything out but it's not hard, don't have time to look it up right now though but I've done it before on a coil I thought was bad turned out to be wiring issue. Coils don't go bad often.

Off to run a 5k. Have a great morning!

To physically check a coil with power off and disconnected from the chain, you would be checking resistance. If it is infinite or really high then the coil is bad, I think it should have like 8-12 ohms if I remember correctly.

I think its 3-4 ohms but I may be way off on that one. I can't remember exactly either.

Yea I agree, it should not be over like 10-12 I think, low is fine. Check the guides to be sure but really you are looking for high resistance.

As a minimum, that's correct.

Power off.
MM set to measure resistance (ohms), so set your meter accordingly.
Put the black on one outside lug, the red on the other.
Doesn't matter which color on which lug, mix and match all you want. Put one on the center lug if you want and measure that. Doesn't matter. There is no way to damage your coil or your machine or yourself by doing this. (power off, remember?).
You are looking for a minimum of 3 ohms. If you can't get that reading consistently across the lugs, the coil is probably dead. It might be much much higher , even 25+ depending on the type of coil and it's use. Doesn't mean one is better than the other. It's just the way that particular coil is built. Just look for a minimum of 3 ohms.

If the power is off to the machine - unplugged - you can pretty much poke your MM around anywhere under the playfield and search for readings like this on coils and diodes, etc. You can't hurt anything even if you put your probes in totally illogical places. So no fear.

Yes. you're better off testing while the coil is off the machine. That way you have it completely isolated.