Hey guys, I wanted to share the lighting mods I made over the years to my BK. I created a separate thread because I didn't want to clog this one up with a ton of pictures. If you're interested in seeing them the thread is "Black Knight lighting mods"

and is here:

https://pinside.com/pinball/forum/topic/black-knight-lighting-mods#post-4080507

Did the game ever once function properly since you had the machine in your possession? If it is't a stuck switch (which you already tested for) then i'd start a new game, remove the ball from play and individually examine what happens if you manually, individually press each switch in the upper PF ball lock. If the switches are somehow reversed that may try to kick out a ball prematurely. Did you try taking all balls out of the machine and see if you get any switches reading ON during a switch test?

Does anyone know if BK will allow a new game to start if there is a ball missing?

I think I know the answer to what I'm about to ask but just wanted to be sure so I'll ask it here. The Jet bumper coil in my BK is stuck ON. This is the only problem. I am guessing the TIP102/120 for this coil is most likely fried and needs replaced? Also, when I look at the manual it says transistors Q4 and Q6 control the coil. Why are there two TIP102/120's for this coil when all others have one TIP and a corresponding smaller pre-driver transistor? Also, could it be Q4 or Q6's pre-driver transistors (Q5 and Q3) causing the issue? The coil locks on instantly when the machine is turned on. Everything else in the machine works perfectly. Aside from fried transistors is there any other common problem to check for that could cause this issue?

Thanks!

Thanks for the info. What type of transistor is the pre driver Q5, and are there any substitutes or other compatible transistors (similar to tip102/120 cross compatibility)?

Alright so a few weeks ago I posted as well about a stuck coil, the pop bumper on my BK. I have since replaced the transistors at both Q5 and Q6. Prior to replacement the coil would lock on instantly the moment the machine was turned on. When I replaced the two transistors and turned the machine on for the *FIRST TIME*, the coil was NOT stuck on. I figured the problem was corrected. I tried playing a game to test the game and the moment the pop bumper skirt was hit the coil stuck on again. I immediately turned the machine off. After that the coil was permanently stuck on again. After that initial power-on, every single time the machine is turned on the coil locks on immediately when the machine is turned on, just like before. I removed the Q6 transistor from the board so I could power the game back on without the pop bumper coil locking on. I ran a switch diagnostic. I noticed that when the pop bumper skirt was pressed while in diagnostics, switch 36 (pop/jet bumper) would not register as ON. Aside from that everything else in the machine works perfectly. Someone had suggested that the culprit may be IC6 or IC8. If it were one of these IC's wouldn't an entire row or column in the switch matrix fail? Maybe I'm mistaken but it seems that if it were an IC issue it'd be incredibly unlikely for ONE single switch/coil to fail. Where should I go next here? Replace IC 6 and/or 8 or is there something else more likely? Not to sound lazy but I'd prefer to exhaust all of the easier-to-fix potential issues before cutting off and replacing IC's on the driver board which is a huge pain.

Doesn't this circuit get disabled by a relay while in attract mode (along with flippers) ? If that's the case then it couldn't be the switch on the flipper skirt shorted, right? Otherwise it wouldn't be locked on in attract mode.

If that's the case then in what possible scenario could the pop bumper coil lock on the instant the machine is turned on (and in attract mode)? Even if Q6 were shorted or an IC were defective the coil should only lock on when a game is started and not in attract mode due to the relay that disables that circuit in attract mode, no?

Ok thanks for the clarification. I guess I'll be swapping out ic6 and 8.

Regarding my similar coil issue, I did some exploring under my cab last night and noticed the coil diode on the pop bumper coil vibrated loose from the solder on one of the lugs. I read in another thread somewhere that on this era Williams machines, without the coil diode intact (to prevent voltage spike) on a special solenoid that one single pulse of the pop bumper coil could essentially fry the driver transistor. I did indeed notice that when I replaced the TIP 102 and turned the game on for the FIRST TIME, the coil was not locked, but the moment the pop bumper skirt triggered the coil it immediately locked on and was permanently locked on thereafter, even after shutting the machine off and turning back on. After this happened I tried yet another brand new TIP 102 and the exact same thing happened, no lock until the coil was triggered once, then it was stuck locked on. I figure I just fried 2 brand new TIP102's.

I haven't had a chance to replace the diode, but does this sound like a plausible explanation for my problem?

To anyone interested, correcting the disconnected coil diode fixed the problem. If that diode goes bad or is disconnected it will immediately destroy the driver transistor the moment the coil is triggered.

Please confirm... in the default settings, two or three captured balls intended to start multiball do NOT carry over each turn if multiball is not achieved before round is over, right? Meaning you need lock two/ three balls AND achieve multiball on the same round or else the locked balls don't count and the locked multiball counter resets, correct?

Thanks!

I love this game but gonna voice my one complaint about BK... some may even say it's a coding glitch. During multiball if you hit the magnasave button, by default it should activate for I think 5 seconds. I noticed that if a target bank is completed while one of the magnets is activated (and the other magnasave is already lit), it will shut off the magnet and reset/relight the current magnet. Seems rare but I've lost many balls that were orbiting the magnet that did not have time to slow down. Seems like they should have coded this so the current active magnet finishes it's full 5 second cycle. Hope this makes sense. There, I'm done.

Dumb question, If I'm not mistaken the flipper coils use 50v before the eos switch is flipped, but do the coils for the kickout holes and drop target banks also use 50v or is it less?

Thanks for the info!

This is interesting to me since I have also attempted to clean these posts in my Taxi with not much luck. It seems like the old dry, worn out rubbers leave a residue/grit that is just impossible to remove completely from the plastic posts. This question may belong in the restoration forums but does anyone have any tips on how to restore these things to a like-new appearance? It would be nice if it was possible to restore the original posts if someone were OCD about original parts/authenticity and such.

Thanks, I will give it a try.

Rules question here:

Which events add score to the end of ball bonus? I know the U-turn increases the bonus multiplier, but what events actually add banked points to the bonus you receive at the end of a ball versus points you receive real-time as the event is actually happening during game play?

3,000 points?

Back to my original question, you mean that each time a bank is completed it adds 1k to that round's end-of-ball bonus, yes? Does anything else add to this value (e.g. pop bumper, slingshots, spinners, etc.)?

Makes sense, thank you for clarifying!

Audit/adjustment question here.

I'm trying to reset the high score to date (adjustment #13). I already cleared and reset the bookkeeping/audits and I set adjustment 13 to my desired high score to date at 600,000. For some reason no matter what i do i cannot get high score to date any lower than 2,500,000. It always defaults to that initial score until a higher score is achieved. Is this the minimum allowed or am I just missing something obvious here?

Also, will BK retain the top four highest scores and display them in attract mode or only the all time high score to date?

Yes, reset switch was pressed. The high score was reset but down to 2,500,000. There was a high score somewhere in the 3 millions prior.

Crazy question but does anyone know the strength in Newtons of the energized magna save coil?