Hey everyone,

Just recently bought my first pin, a 1980 black Knight! I've been having some issues trying to track down an issue with the lower eject hole not working. It's the multi-ball eject to be specific. The leaf switch registers when a ball is there, but I never get an eject. I tested the resistance on the solenoid and I am getting around 3.8 ohms, so I don't think it's an issue, maybe power? I can go into test mode and when solenoid 8 is tested, nothing happens, all other solenoids do not have this issue. I'm thinking this could be a driver problem or some advise to fix this issue. any help is appreciated, for right now I'm a bit of a noob

I'm not sure I follow, if I put a ball in the hole the game senses it, but it never ejects the ball. Are you saying there are 2 switches? 1 for the multi-ball and another to eject it?

In switch test none of the switches stay open as it goes through all of them, in solenoid test the lower eject (#8) never pops the ball out .

Thank you for the suggestion, I'll try that and report back.

Speaking of which, how did you know which one of those goes to that solenoid? Would be useful for future reference on this game of mine with future repairs.

thanks a ton kind sir . I have one more question, are these solenoids like fuel injectors where power is going to them all the time but ground is what activates them from the driver board?

Just wanted to update, the coil does fire when it's in attract mode and is grounded out. Looks like this might be a driver problem and/or a cabling issue with the ground which I will test next.

As far as parts to buy, I've read there is a pre-driver and the driver (transistor) itself. Is this the right transistor to get? From the manual it looks like 5A-8977, but do I need a resistor to replace on top of that or anything additional?

https://www.marcospecialties.com/pinball-parts/TIP120

anyone confirm on the pre-driver and transistor I need to replace?

Not to bring a thread back from the dead, but I finally got around to testing this machine. So grounding out the transistor does NOT fire the solenoid, but grounding the solenoid out does.

I also tested the transistor from steps here:

https://www.pinwiki.com/wiki/index.php?title=General#Testing_a_Transistor.2C_Silicon_Controlled_Rectifier_.28SCR.29_or_Field_Effect_Transistor_.28FET.29

and the transistor tested good. So now I think I'm having a physical connection problem with ground to the solenoid.

Any tips/tricks into finding the broken wire (if there is one)? I'm starting at the connectors first, but when doing a connectivity test, multiple pins "beep" so just looking for some guidance here.

Thank you in advance!

Here's what I've found so far, GRY-BLK all the way to the solenoid.

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So I traced down the wires but this one wht/red (I think?) was connected to the ground strap at the base of the head.

Connectivity was good from both connectors to the solenoid but I'm not sure if this why/red is supposed to be connected to the grounding strap as you see me point out in the photos.

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Nevermind about the wht/red wire, found the answer here.

https://pinside.com/pinball/forum/topic/black-knight-clubmembers-only/page/4

Now about the transistor not firing although it tested good, what should I do next? Pull the driver board and look at traces?