(Topic ID: 206406)

Tech: WPC Demolition Man DMD Not Working


By JAG94

1 year ago



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  • 9 posts
  • 6 Pinsiders participating
  • Latest reply 1 year ago by schudel5
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#1 1 year ago

I just picked up a Demo Man and am having an issue with the display. I have tested the DMD itself, and it works no problem. When I turn the machine on it will make the sound as if it is booting, but will not allow a game to start. When I press exit on the coin door after start up it will go into attract mode, but still the display remains blank. Once I get to this point I can add credits, start a game, and it plays with no issues. Any help is greatly appreciated.

#2 1 year ago

have you tried pressing on the asic chip on mpu to make sure its seated?

#3 1 year ago
Quoted from PinsideTroll:

have you tried pressing on the asic chip on mpu to make sure its seated?

Yes, it is seated. As of now the only thing that isn't working properly is the DMD, and as I mentioned before I did test it in another game. Ribbon cables also appear to be fine.

#4 1 year ago

Have you checked the dmd controller board? Review my restore thread if you get a chance, it goes into depth of checking voltages to the dmd and the dv section of the dmd controller board.

I also had to troubleshoot my dm when my dmd was out and play it blind. The, Wah wah wah noise is saying there are issues or check for something warning, then you press exit and get it into attract mode... you can't easily identify the issues unless you get a display but you have a goor chance its the coindoor interlock disabled warning as you have the coindoor open.

#5 1 year ago

Fuse maybe?

#6 1 year ago

Did some snooping and this is what I found, though I don’t have a schematic for the board. No fuses out. Do these resistors manage the DMD?

4D56ECED-5B11-4C3C-BAAD-4A51D6E93447 (resized).jpeg

#7 1 year ago

That's the mai. Cpu board. Clean it up before anymore testing.

#8 1 year ago

Those resistors and ICs are toast. I’d bet if you’re going to find a bunch of other crazy things going on with the gameplay on that machine. I don’t know what other games you have but you could always try a different mpu in the machine to see if that would solve your dmd issue. Typically I’d side with trueno92 on this one and say it’s typically the controller board though

I’ll gladly drive down and take that DM off your hands if you need me too

#9 1 year ago

Those resistors are on the CPU and have nothing to do with the display. They basically handle the switch matrix. It does need to get cleaned up, but don't have anything to do with the DMD.

Your issue lies on the DMD controller board and in particular the HV section in the bottom 1/3 of the board. Typically those components are burned and need to be replaced.

http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Display_problems

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