Data East DMD problem - any ideas..?

highjon

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Any ideas why this Data East Rocky n bullwinkle DMD would do this...?
The game runs and the graphics are actually running although too gargled as you can see.
All voltages correct and present, have done lots of reading online before asking but I m stumped..
One guide hints at a resistor being faulty R95 but this board doesnt have an R95 but all resistors are reading correctly..
Has anyone came across this before..?
thnxde dmd.jpg
 

Jagspete

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Freakin’ wow!!! Genuinely this is exactly what happened with my R &B last night after turning it on for 1st time in year and a half! Was fine for about 10 minutes , then gradually faded to the same as yours. Tried reseating all connectors letting it ‘cool’ for an hour, in the end I swapped it out for another and all fine now. Mine was original from 1993 so I’m guessing that 28yrs is the lifespan. On another note, you have any spare plastics?
 
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highjon

highjon

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Freakin’ wow!!! Genuinely this is exactly what happened with my R &B last night after turning it on for 1st time in year and a half! Was fine for about 10 minutes , then gradually faded to the same as yours. Tried reseating all connectors letting it ‘cool’ for an hour, in the end I swapped it out for another and all fine now. Mine was original from 1993 so I’m guessing that 28yrs is the lifespan. On another note, you have any spare plastics?
You ll be glad you had a spare lol I dont... My DMD is a Babcock type which it talkss about in pinrepair pages but the R95 resistor issue doesnt match my board.. It also says check your 18volt fuse as the board takes 12v from there and not the 12v supply on some boards, whch also cause this.. Im still stumped I must admit :-(
 
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highjon

highjon

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Freakin’ wow!!! Genuinely this is exactly what happened with my R &B last night after turning it on for 1st time in year and a half! Was fine for about 10 minutes , then gradually faded to the same as yours. Tried reseating all connectors letting it ‘cool’ for an hour, in the end I swapped it out for another and all fine now. Mine was original from 1993 so I’m guessing that 28yrs is the lifespan. On another note, you have any spare plastics?
Sorry mate, no spare plastics either ..
 

keith b smith

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( I take it you Have you checked the 8amp fuse by the big blue capacitors inside the back box )also the bridge rectifier by the side of the capacitors
cheers
Keith
 
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astyy

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Dont be nosey :-)
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highjon

highjon

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( I take it you Have you checked the 8amp fuse by the big blue capacitors inside the back box )also the bridge rectifier by the side of the capacitors
cheers
Keith
Yes, I have checked the fuse its ok, also just checked the adjacent bridge rectifiers which test out ok, although I havent desoldered them or tested under load...
 
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highjon

highjon

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Would the R&B dmd work in the Dredd?? are the voltages the same, I hadnt thought about that...hmm
 
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highjon

highjon

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John,
Try the R+B DMD in your Judge Dredd just to rule out that it's the DMD at fault.
D.
Mate I dont think that would work, the voltages are different on the pins.. dont want to cause further damage, but yeah could do with a similar de machine
 

Jagspete

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It would be quickest to rule out the dmd than try to find a fault else where. I’m sure the dmds are interchangeable between Bally and data east as fitted a Cherry one ((from a DE machine)to my doctor who when it went the same way. I tried reseating all the connectors when the screen did the same on my R&B to no avail , the stern dmd I straight swapped has worked without issue since so it can’t have been down to fuses or bridge rectifiers.
 

Calimori

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Joining in. My Tommy did this after a while of being on. Now it is solid lite.
I have a few spare DMD panels so will swap over later and report back
 

Calimori

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Spot the difference in DMD from Tommy vs the one that came out of a WIlliams game
IMG_7596.JPG
No point, they both have a Williams sticker on them as they are both from a Williams game. Tommy clearly had a DMD from another game switched in.
The graphics driver board is mounted to to the back of the DMD which I guess deals with the voltages and other differences.
 
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Calimori

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For my issue, I moved to connecting cables and swapped those I had out for others. Graphics board to DMD, plus Graphics board to CPU board.
Same issue.
When I returned to fitting the originals cables I got distracted and now pin 1 on pin 1 on each causes the machine to trip. If anyone can share a picture of how they should be that would help ;).
 

Calimori

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Thanks again. I thought I tried everything yesterday but clearly not.
Back to where I was with a solid lit DMD
cff4bffb2d3750461eb041d2ecd3b2db.jpg

Previously, it was the same as other and went funny after time.
Next I will test the voltage.
 
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highjon

highjon

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I have looked carefully at my DE DMD and it is totally different to the bally DMD in my dredd, the voltage pinouts on the cable are also totally different so Im not going to try plug these in to each other, I reckon I'll simply blow both machines boards...
regarding the R&B dmd, I still turn it on every night in the hope that the pinball fairies have fixed it :)
they havent
 

andy

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I have looked carefully at my DE DMD and it is totally different to the bally DMD in my dredd, the voltage pinouts on the cable are also totally different so Im not going to try plug these in to each other, I reckon I'll simply blow both machines boards...
@highjon what are the voltages you think are different? Bally/Williams, DE/Sega and Gottlieb games all used interchangeable DMDs as far as I’m aware.

Look at the game list on this:

https://pinparts.co.uk/products/dot-matrix-display-128x32
 
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highjon

highjon

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On checking, thanks, it looks like only pins 1 & 2 are a little different from each other, dredd pin 1 - 125v R&B pin1 - 110v, Dredd pin2 - 113v R&B pin 2 - 98v, not that much of a difference so maybe your right..
the other pins are the same volatges.....hmmm
thanks for making me look again
 
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