DMD fault

[tronads]

I am a complete pinball virgin when it comes to faults and repairing them, so I would greatly appreciate any advice on this one....
The machine is an Addams Family, and the DMD is showing an extra line on each character on the display.

I'm hoping it could be something pretty simple ???

 

[Hurray Banana]

Looks like some data line is stuck high as it repeats for the same bit of each character row. Never had to fault find on a DMD but could probably be connector/pin related. try making sure ribbons connected to board and back box board.

I'm sure someone more knowledgeable will chime in

 

[tronads]

yeah, I was thinking a pin stuck high on one of the IC's on the DMD controller board as it is, as you say, consistent.
I was thinking if it was connector related they would be more likely to be missing rather than constantly on though...

 

[Hurray Banana]

Like I say, it's the one part of a pin I haven't had to work on (yet!), inverted inputs maybe, but it is probably gonna be an ic failure.

I have had a lot of problems with header pin problems because of dodgy/cracked through heat and vibration, so worth checking for those as well before trying to hunt down an IC.

 

[taz turbo]

I've had the same or very similar on my FishTales, as already suggested it was one of the ribbon cables connecting the boards together. On moving one connector about the fault would clear, I spayed the contacts over with contact cleaner then connected and disconnected several times, I gave the same treatment to all of the ribbon cables. It's been fine since.

Chris.

 

[Sciddleybop]

To be on the safe side you should probably just sell the whole machine. I'll step up and take one for the team. I'm a great guy like that.

But yeah defo reseat the ribbon cables. Even try the short ribbon connector between the cpu board and the big board

 

[tronads]

Good grief, it took me 2 years to get round to this, I only got there tonight !

 

[Hurray Banana]

Did you fix it though?