OK I shorted the pin and the machine went into test mode.
It seemed to me that a few solenoids did not work. Unfortunately, after three passes, the time it took me to start understanding the sequence, the only fuse I had left blew. I'll buy some more tomorrow but for now I'm not too sure what to think.
It seemed number 7 didn't fire up. It's the bumper one. It reads 10 ohms, like the other similar coil (loop target one, which definitely works). What else could be wrong with it and how do I determine the problem ?
I should add that the few times I started the game and before the fuse blew, the big target bank acted wonky, which may have prevented other coils from firing (the loop target one or the two other small drop banks) since the game can only do one thing at a time, but I never saw any other coil fire up (for example the ball kickout hole or slingshots).
If I disconnect the big bank and start a game, the loop target coil is the only one functioning. It may be because the big bank coils precede the other coils except the loop target one. It may also explain why an issue with one of the big bank coils may prevent the rest of the coils from firing up.