Black Knight Magna Save issue

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I have a Black Knight that has worked great in every way for the last year. All of a sudden, the right magna save no longer works. It lights up like it's on (it kind of flashes when you engage it, like it's supposed to) so I know the button is working. The left one still works fine. I haven't had a chance to dig into it yet, but is there anything as simple as a fuse that may have blown? I took a quick look underneath and didn't notice any loose wires or anything. Ideas on what to check?

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I'll try to check those tonight. It's good to get some confirmation that it may be something that easy. We'll see. 

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I checked last night and feel better and worse at the same time. I feel better because I was able to eyeball the process and how it all works down there. I looked at the left side and saw how things operated and then found the area that was not working on the right. It turns out that the magnet is working but there is a solenoid that isn't firing that turns on the magnet. So I feel good that the magnet is working but bad that I don't know why the solenoid is wonky. I brought the manual in to work today and will try to trace the issue there. Fuses look fine and I swapped them just in case and nothing changed. I'll have to crack out the multimeter and see if I can figure out if it's a wiring thing or a solenoid thing.

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The button causes the small solenoid (the size of half a Certs roll) to activate which forces a leaf switch to make contact. That leaf switch operates the magnet. I could manually move the switch and felt the magnet turn on. One of the wires from the solenoid connects in a chain to the kicker that sends the ball back onto the field from the lock on the bottom playfield. That still works so I know that wire is good. There's a brown and black wire coming from the solenoid that I have had trouble tracing because it gets grouped in with a bunch of other wires immediately. I'm hoping the manual will give me some insight when I crack it today. The magnet is the only thing not working so at least it's confined to that one thing.

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Good progress last night. I ran the diagnostic on the solenoids and lo and behold that solenoid (#9) didn't fire. I hit it with the multimeter and it was sending the signal which told me that the solenoid was bad. Just for grins, I ran a few wires from the bad solenoid to the good one on the left and it fired on the left. Whew! The solenoid is a $7 part so I'm pretty stoked. I read online that the solenoid in the coin door lockout is the same one so I was hopeful that I could just swap it out. Unfortunately, that one is no longer working either. I'm thinking of buying a couple just so i have a spare in case it happens again. I don't plan on changing the coin door lockout solenoid as I don't need it. I love it when a plan comes together.

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I was about to pull the trigger on ordering the solenoid from Marco ($8.50 plus $8.50 shipping, ouch! I need to find more to buy) when I started thinking about whether the solenoid was repairable. Do they really go bad? What goes bad? Aren't they just wound wire that produce a magnetic field? All this one does is pull a metal flap down when it magnetizes. The flap completes the big magna save magnet circuit. The wiring is all intact. I guess I'll just get a new one regardless.

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I tested the coils through the diagnostic setting on the machine. It fires each one in succession and I can stop it on any of them. When it got to #9 I could measure the electricity pulsing with my multimeter, but no firing of the coil occurred. Same goes with the coin door lockout, measured the pulsing but no firing. I'll do a visual to see if I notice any breaks in either one. Thanks for the insight.

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I received the replacement coil in the mail yesterday (highly recommend Marco for their prompt shipping, prices are up there compared to some places but the selection is excellent). It was easy to replace, two solder points and one screw holding the small coil in place. 5 minutes later I fired it up and hoped for the best. I hate this part because if it doesn't work, I'm back to square one. I put it into the solenoid test mode and waited for #9 to cycle through. Nothing. Crap! I took another look and wiggled it around a bit. It turns out I placed it in slightly off kilter and when I wiggled it, it popped into place so I could tighten the screw some more. Cycled again and got a click! Started a game and hit Magna Save and the ball stopped in its tracks. Success! I took some pics of the area that I replaced but forgot to bring them with me today. I'll post them tomorrow for anyone else who ever has this issue. I took a good, hard look at the broken coil and didn't see any sign of burn or broken wires. I didn't unwind it so the break must be there somewhere. I don't doubt that one of the many kids (my own and their friends) that played it at some point found a way to burn it out. But, hey, all's well that ends well. A relatively cheap fix.
I also finally got around to putting the knight stickers on the drop targets. They were gone when I bought the machine and I found a file to print them on sticker paper. I got some mylar from Marco along with the coil and stuck them together. Looks great now and a lot more complete.

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Here are some pics for posterity.

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No I didn't. That probably would have been a good thing to do, huh?