(Topic ID: 321261)

BK2k Magna Save Matrix issue

By bernieberg

1 year ago

Topic Stats

  • 7 posts
  • 3 Pinsiders participating
  • Latest reply 1 year ago by frunch
  • No one calls this topic a favorite


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#1 1 year ago

Hello. My BK2K will incorrectly register magnasave when hitting the right flipper button ONLY if the trouph 1 switch is active. No other switches on the magnasave or trouph 1 column or row do the same thing. If the trouph 1 switch is not active, the magnasave switch works normally (from the edges test)

Any suggestions what to check?

I've tested (and replaced for good measure) the diodes on the magna save, trouph 1, and right lane change switches. They all tested fine.


#2 1 year ago

I have found that there is a separate but related issue. When the right most motor bank target is pressed it also registers the right eject. There don't seem to be any obvious ground shorts, I followed the wires as well as I could.

What would you suggest for further troubleshooting? Should I be testing all diodes in all the affected columns/rows? Could there be a ground issue somewhere on the interconnect board?

Thanks for any suggestions!

2022-08-29 20_22_20-Black_Knight_2000_OPS.pdf (resized).png2022-08-29 20_22_20-Black_Knight_2000_OPS.pdf (resized).png
#3 1 year ago

Couple things to try/check out:

Put the game in switch test, then remove connectors 1J8 and 1J10 from the MPU. Take an alligator jumper and clip it to the first pin on 1J8, then use the other end to touch each pin on 1J10 one at a time. That will simulate the switch closures for the first column of switches. Watching the displays, you can verify whether each switch is being detected properly at the MPU. Once you've tested all the switches on column 1, move the clip to the next pin on 1J8 and run down the same procedure. If everything works properly at the MPU, you'll know it's a playfield issue.

Another thought: a lot of times, switch matrix problems like this can have a pattern. They often make a square or rectangle on the switch matrix chart when there's an issue with a stuck/shorted/mis-wired switch or diode. In your case, the switch that's standing out to me is the "playfield tilt"... Acting as a 'corner' it makes the 'rectangle' with the other 3 switches related to the problem. See here:


So my suggestion would be to verify that the playfield tilt switch wiring and diode are correctly oriented (make certain the wiring is correct, no diodes backwards or wires going to wrong lugs, make sure tensioner blades on the switches aren't causing shorts across the switch blades, etc), and make sure the switch itself isn't stuck closed somehow. Verify those same things at *all* the other switches on columns 2+8. Also note the flipper switches referenced in Column 8 are the low-voltage switches attached to the flippers (not sure if they're on the flipper mechs themselves or stacked on the cabinet flipper buttons... They're used for the lane-change feature)

#4 1 year ago

Thanks frunch I'll give these suggestions a try this evening. And to confirm the last thing you mentioned, yes the "flipper right" is the lane change.


#5 1 year ago
Quoted from frunch:

Also note the flipper switches referenced in Column 8 are the low-voltage switches attached to the flippers (not sure if they're on the flipper mechs themselves or stacked on the cabinet flipper buttons.

Switch 57 and 58 (flipper switches) are the 4N25 optocouplers on the Interconnect board. They are NOT physical (leaf or micro) switches.

Switch 59 (Magna Save(tm)) is a leaf switch in the cabinet.

#6 1 year ago

frunch you were exactly right. I tested the MPU like you said, and it tested fine. I did a bunch more search of old posts and found out that the "playfield tilt" on bk2k was actually never installed from the factory, but the wires are still just dangling around. It seems that it has caused issues for other people in the past:


I just clipped the wires and everything is working great now. All other switches seem fine, so there does not seem to be any other side effects to clipping the playfield tilt wires (I clipped them at the diode).

Thanks for your help! your suggestion on the playfield tilt got me going down the right path.

2022-09-01 21_34_16-Photo - Google Photos (resized).png2022-09-01 21_34_16-Photo - Google Photos (resized).png
#7 1 year ago

Excellent! Glad you found the culprit and fixed it. Thanks for following up with the solution!

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