Trying to diagnose a display corruption problem on a Data East Teenage Mutant Ninja Turtles. This is one of the Data East games that uses the "small" 128x16 DMD display (the others being Checkpoint, Batman, Star Trek 25th Anniversary, and Hook).

The original DMD was outgassed, a PIN-LED replacement works 80% of the time, but I get some display corruption. Trying to figure out if it is the display or something else that is causing the corruption.

I've tried a number of things:
* Rebuilt the P/S board (caps and connectors). I've got a good solid +5VDC going to the DMD board.
* Tried a different DMD ribbon cable.
* Replaced the PROMS on the both the CPU and DMD boards. Both are 1.04 (the latest).
* Replaced the 6821 PIA at B8/9.

Nothing resolved the problem.

I'd like to try another display if someone local to the Philly area has a working 128x16 display I could try. That will help me focus in on where the problem is.

PM me if you can help.

Bill D.

Going to be hard to get pictures because the images don't stay on the screen that long...

I'm not at the game right now, but I'll try to be more descriptive what I'm seeing:
* Most of the time, when first turning on the game, everything displays OK. It usually takes a few minutes of play before I notice some display errors. Things that displayed OK, now will be corrupted or not displayed at all. Some examples follow...
* Some of the graphic images are corrupted (pixels scrambled). Not always the same ones. Sometimes they display OK, sometimes not. When this happens, I think it is always the left side of the display that is corrupted.
* Sometimes the display will just go blank for certain display sequences and then come back on when a something new is displayed on the screen. For example, at the beginning of a ball, with the ball sitting in the shooter lane, sometimes nothing will be displayed on the screen until the ball is launched.
* Sometimes when the display goes blank in the middle of a game, it will stay that way until the end of ball displays the bonus sequences.
* A few times the display would just freeze on a certain image and the only way to recover was re-boot.
* Unexpectedly during play, it will sometimes display the display ROM version ("DISPLAY VER: A1.04") and sometimes the words "DISPLAY VER" part will be corrupted.
* One time it displayed "RCVR OVERRUN". This only happened once and haven't seen it since.
* I have the game set on Free Play. Most of the time it will say "FREE" where the number of credits is displayed on the DMD, but sometimes I've seen it display "0" instead of "FREE".
* The corruption and blank outs seems to be more frequent when playing a multiplayer game. When it has to display multiple player scores on the game at the same time, sometimes that will work for a while, and then the display will blank out when it should be displaying the scores.

Very hard to describe... Maybe I need to take a video and post it to youtube.

It's been determined that the new display board is bad. So, now looking to buy a used/working OEM DMD and board.

http://pinside.com/pinball/forum/topic/wtb-16x128-data-east-dmd-and-board