Problem With DMD, Any Ideas Please ?

[DRD]

I bought a Shadow this week. When you first turn on the game the DMD is fine. It plays fine too. But after about half an hour, this happens when you leave the game in attract mode. The bars will also just appear mid game. These bars remain when you play a game too. When you put it into test, the bars remain too.



When you go to the display test the vertical bar runs left to right on test, all the rogue bars disappear apart from 1. (Note. The flash in the middle of the display is the camera flash) There is the moving bar you would expect moving left to right, but also a second rogue bar appears. This is effectively "bounced" left to right by the moving bar. When the moving bar hits the rogue one it jumps about 8 columns to the right. When it gets hit again, it jumps another 8 and so on.




Turning the machine off and restarting does not clear this. The bars may remain for perhaps hour or so, then they just go of their own accord !! Leaving the machine turned off for a while clears them too.

I have tried two different DMD display panels on the game. Both do the same thing. So the problem must lie with the Pinball itself. It is not caused by vibration as these bars come and go when the game is left in attract mode.

Any ideas please ?

 

[Spandangler]

Try reseatting the ribbon connector at the board end

 

[Sgt GrizZ]

Or swap in cables from another machine and see if any change.

 

[Spandangler]

Or even try reseatting the short ribbon connector between the CPU board and whatever the other board is

 

[Pudsey pinball]

Reseat all your ribbon cables and ensure the dmd ribbon is the correct way around..ie... The red stripe on ribbon is at pin 1

 

[Big Phil]

Reseat everything!

 

[pinballmania]

With power off , push firmly all round the edge of the square chip on the CPU with your thumb. You'll here it creak as you push around the edge.

 

[DRD]

Thanks for all your suggestions

I swapped the dmd driver board with my (seemingly identical) one on twilight zone as the games are of a similar vintage. Both machines now seem perfectly happy with their exchanged boards

Some sort of loose connection I suspect. I did get a molex pusher tool, so subjected the relevant shadow connectors to that too

If the issue reappears, I will try the square chip push too

 

[Spandangler]

sorted