(Topic ID: 251492)

Black Knight: MPU lockup?


By kevinclark

9 months ago



Topic Stats

  • 3 posts
  • 2 Pinsiders participating
  • Latest reply 9 months ago by kevinclark
  • Topic is favorited by 1 Pinsider

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#1 9 months ago

I’m having a rough night. Thanks to this forum I had my BK playable. I was swapping rubber rings and had pulled out the novus #2 to clean. I went to show it to a friend and play a round, but one of the upper flippers was locked up again. I adjusted the switch and no change, so I went to ground the coil to make sure that part was still ok and I got no response. Then weak response on the other upper flipper. Then I smelled the burning.

I can’t tell where things got fried, but the two leds on the MPU board light and stay lit when I give it power. This page (http://pinball.flippers.info/system6repairpart4.asp) suggests a test rom is my next best option to debug, but suggests something can be done with a test led (though it doesn’t elaborate since test roms exist). I don’t have a rom burner. Do I have another option to isolate the problem or do I need to get one?

Edit: Ah, reread and I found the section for debugging without a test rom. Would be very interested in any advice for going down this path however.

#2 9 months ago
Quoted from kevinclark:

I’m having a rough night. Thanks to this forum I had my BK playable. I was swapping rubber rings and had pulled out the novus #2 to clean. I went to show it to a friend and play a round, but one of the upper flippers was locked up again. I adjusted the switch and no change, so I went to ground the coil to make sure that part was still ok and I got no response. Then weak response on the other upper flipper. Then I smelled the burning.
I can’t tell where things got fried, but the two leds on the MPU board light and stay lit when I give it power. This page (http://pinball.flippers.info/system6repairpart4.asp) suggests a test rom is my next best option to debug, but suggests something can be done with a test led (though it doesn’t elaborate since test roms exist). I don’t have a rom burner. Do I have another option to isolate the problem or do I need to get one?
Edit: Ah, reread and I found the section for debugging without a test rom. Would be very interested in any advice for going down this path however.

You have a BK with dual LEDs, not a single digit numeric LED display?

Dual LEDs can mean a myriad of things from bad ROM sockets, to bad ROMs to bad chips on the board.

Do you have a logic probe? First thing to check is to verify the CPU is running by looking for activity on the address and data buses.

#3 9 months ago

Apologies, when I drained this I thought it deleted and I reposted with better information. I have a logic probe and I got the pincoder test Roms working. Pretty sure it’s a bad PIA.

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