DMD Problem

[MaineEvent]

Anyone know what causes this?
This is a Bally Doctor Who if that makes a difference....
I tried disconnecting and reconnecting the cables to the DMD and board
I metered the fuses and big caps including the "brown devil", checks out
I looked at the back of the board and didn't see and obvious trouble signs

Any help would be appreciated 

[smartbomb2084]

It is highly likely that the display itself is toast. It looks a little outgassed.

Check the voltages at the connector right on the display.

Be sure your ribbon cables are on right. Red stripe to pin #1 on all of them.

The best trouble shooting move here is to have a known good display to try in the game....Sorry.

[ChadTower]

Look at the driver board itself.  That could be burned up.  Very common.

[ChadTower]

You can find rebuild kits for the driver board here.  I have used GPE many times.  This rebuild isn't a hugely advanced task but it does vary depending on how much physical damage has been done by the heat.  Sometimes just a simple swap of all the components does the job.  Other times you have to track down burned traces or even improvise a way to hold a new header in place because the old one is now sitting in a half inch round hole.  

I recommend jumping any questionable traces in the circuit.  Yeah, it's a bit of a pain, but half the time they buzz out fine on the meter but under load they aren't quite solid.  You end up with a DMD that "needs time to warm up" or flickers at random times.

[smartbomb2084]

The logic section of a DMD Controller board rarely goes bad it is the high voltage power section that always cooks.

In this case the High Power section is probably good or we would have no 'Lit' dots at all.

And just to remind the forum's resident pinballjerk, displays do outgas, that wavy look is outside air mixed with it.

Once again, he ought to read the CLAY guides he so often bashes a little more closely.

[MaineEvent]

Thanks for the input guys.
I haven't had time today to work on it again... I did look at the power board yesterday and didn't see any obvious sign of damage...
Yes, I put probably 1000 games on this without issue before the DMD had this problem.
Hopefully I can get something done tomorrow and let you know how it goes.

[smartbomb2084]

I've had three Williams pins with similar issues and a HV rebuild kit cleared it up.

More Texas BS.

[ChadTower]

I've had three Williams pins with similar issues and a HV rebuild kit cleared it up.

More Texas BS.

I have had two Williams pins with this issue and an HV rebuild kit cleared it up.  One also needed a new DMD.  I have also done this for 3 other games that were not mine.

[MaineEvent]

Alright,

I switched it on today... The DMD was still the same ---fouled up beyond all recognition--- up image for about 2 seconds, then it went back to normal.
I played for about 2 hours and didn't see a flicker or anything....WTF?
This isn't the Twilight Zone.....

[Q*Bert_OP]

Guess the gas must have leaked back in.   

 

I have an outgassed DMD...It was dropped, the glass cracked, and the gas leaked out. 

[MaineEvent]

Guess the gas must have leaked back in.   

Check those voltages and give the HV section a visual inspection when it starts happening again.

Will do, thanks!