(Topic ID: 170569)

Need Help with DE DMD issues

By PanaPinResto

7 years ago


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60v check (resized).png
image (resized).jpg
#1 7 years ago

I'm putting a Last action hero back together that's been apart for 3 years. I don't know much about its previous life. I bought it as a project someone else never finished. The last issue I need to work out is that the dmd has horizontal lines in it. I seem to be missing voltage on pin9 but it still works. I've replaced and/or tested everything on the board. All cap and diodes. Tr1,2,3,4,&6. Most resistors except for a few I didn't have. The ones I didn't replace all test good. Both wafer and plug on CN1&2 are new. All boards have been reflowed and all connectors replaced if needed. Not sure where my issue is. Can anyone help. Standing by with my trusty fluke.
Connector CN1 w/o dmd connected.
Pin 1=18v
Pin 2=40v
Pin 3=40v
Pin 4=93v
Pin 7=115v
Pin 9=0v
Pin 10=10.3vac
Pin 11=10.9vac
Pin 12= ground

image (resized).jpgimage (resized).jpg

#2 7 years ago

You can easily connect the DMD in South Park to see what the results are. Just hold the DMD on the outer edges when you turn the game on.

#3 7 years ago

What does the 5 volts and 12 volts measure at the top of the power supply?

#4 7 years ago

Reseat the ribbon cable at both ends at the MPU board and where it plugs into the DMD controller board. Then there is a small ribbon cable between the DMD and the DMD controller board, try reseating both ends of it as well.

#5 7 years ago

Thanks for the help maniac.
The South Park is a packed up project. It's shrink wrapped and i would rather not open it.
At the test points on top of the PS
+12v =11.2v
-12v=14.6v
5v=5.06v
I reset the ribbon cable with no luck.

#6 7 years ago

I had forgotten I had an old DMD from a R&B that was missing one line. I put it in and the lines are gone. It works now. It has a lot of "noise" in the display. The animations have a jittery pulse to them and I hear a buzzing that seems to change pitch as the display changes screens. Is this fixable? Is there any way to fix my DMD with lines in it?

#7 7 years ago

ok so now you need to know what the 65 voltage rail to the DMD is measuring. Can you get to that on the DMD power connector? Though it seems your -115v and- 93v= 22 volt difference is likely where the issue is. There should only be a 12 volt difference between these two voltages.

http://www.pinwiki.com/wiki/index.php?title=Data_East/Sega#Missing_-110V_or_-98V_for_DMD_Display_Power
Section 4.7.7 will walk you through the possibilities, if you're up to repairing the power supply

60v check (resized).png60v check (resized).png

#8 7 years ago
Quoted from PanaPinResto:

I had forgotten I had an old DMD from a R&B that was missing one line. I put it in and the lines are gone. It works now. It has a lot of "noise" in the display. The animations have a jittery pulse to them and I hear a buzzing that seems to change pitch as the display changes screens. Is this fixable? Is there any way to fix my DMD with lines in it?

Still sounds like the similar results with the original DMD shown in your picture. The power supply voltage sounds like the problem.

#9 7 years ago

The 68V will be the problem. A 22V difference in the negative voltages is about normal with no DMD plugged in.

Though it sounds like you may have both bad power and a bad display.

--
Rob Anthony
Pinball Classics
http://www.LockWhenLit.com
Quality Board Work - In Home Service
borygard at gmail dot com

#10 7 years ago

so where does the 68v come from. how do i track that down?

#11 7 years ago
Quoted from Borygard:

The 68V will be the problem. A 22V difference in the negative voltages is about normal with no DMD plugged in.

Quoted from PanaPinResto:

Connector CN1 w/o dmd connected.

I missed that.

#12 7 years ago
Quoted from PanaPinResto:

so where does the 68v come from. how do i track that down?

Mentioned in post #7 with the pinwiki link.

#13 7 years ago

Missing 68v, I see it now. Thanks

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