(Topic ID: 166990)

Frankenstein DMD problem

By Ironbum

3 years ago

Topic Stats

  • 12 posts
  • 4 Pinsiders participating
  • Latest reply 3 years ago by Ironbum
  • Topic is favorited by 3 Pinsiders


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#1 3 years ago

I'm working on a working Frankenstein with a dead DMD. Here's the problem, Cap C33, can this be replaced without damaging display attached to it? Is a Cherry A9441.


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1 month later
#2 3 years ago

Hey, I wound up buying a new Vishay display. But when I plug in power to it, whole machine bugs out. Unplugging power to display makes all but display works. Any ideas? I'm only getting 10v instead of 12v as well.

#3 3 years ago

Have you done the power supply fix? Been a while since I worked on mine but I know they are really flaky on the 5 volt.

#4 3 years ago

The wiring harness may be wired different. Look in the Wiring Diagrams in the yellow pages of your manual.
Check the Red, Blk/Red, Black & Blue all go to the proper pins. Dale, Cherry, & Vishay were all wired differently.

#5 3 years ago

Thanks guys, will hit power supply next. I did have to switch the pins for the Vishay, red/blue reversed. So I reversed all 4. Blue has no voltage and new board says N/C.

Latest is, popping the red 12v out of the connector and machine works except for DMD, insert that pin back in and illumination comes on but nothing else, a play field ramp stutters and that's it. No sound, no playability.

#6 3 years ago

Take anther look at that. The Blue comes from the 18v Purple, if I remember correctly.

#7 3 years ago

Thanks, will do!

#8 3 years ago

I'm still stuck, testing power display now. But the Vishay says no +5v on pin 1 and +12 on pin 4. Only getting 10v on pin 4 right now.

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#9 3 years ago

Power supply seems good. I get an unregulated +11 and -14.8. By the time it gets to DMD it's about +10VDC. After unplugging a few times, I got the display working, but blinking. While blinking, machine does not play. I can put credits on and get ball to shoot but flippers and rest of playfield is dead. With display unplugged machine can be played.

Any thoughts would be appreciated!

#10 3 years ago

What do the voltages measure when you unplug the DMD ?

#11 3 years ago

When DMD unplugged they read +11VDC and -14.8VDC. Leaving voltmeter on power supply test points, when I plug in DMD the voltage continually fluctuates between 9VDC and ~11VDC.

#12 3 years ago

Any other thoughts on what to check? As far as I can tell I have a good power supply and a brand new DMD from Vishay. I'm by no means a professional here, most of my experience has been EM and system 1 Gottliebs, so this Frankenstein is a definite challenge!

Thanks for any advice!

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