Matching game ROM and display ROM ?

If one was updated and not the other can be an issue.

LTG : )

I wonder whether there is an issue with the RD CPU board. The behaviour does sound strange but if the cpu is initializing and cand address a specific pia or chip maybe its stuck.

Do any buttons change anything, coins, start, service etc?

Hello...I am facing the same exact problem. Did you eventually find the issue with yours? Any help would be greatly appreciated. For a bit of information...game played fine one day and then the flashing “display version”

Update...when I take batteries out, I get back to the screen working but it says open door. When I do that, the door switch is open and the game works fine. This is some crazy stuff. I have to be able to close the coin door to use this. Ughhh. Any ideas?

Has anyone figured this out? I'm having the same exact problem on a Hook. I can't figure this out.

Sorry for necroing this thread. Did OP and other poster ever find a solution? I was fixing a 520-5055-00 rev-e replacement board from Stern when I found the thread and got some suggestions.

If you disconnect the cable from the MPU board to the DMD controller board (26 pin flat cable) the screen should be on for 2-3 seconds (I believe all DMD controller versions should behave like this but I'm not sure) with the DMD controller boot information (showing '-DISPLAY VERSION- <game name> <ROM version> <date>' information) and then go away since the MPU is not sending anything to the DMD controller. If the reset issue goes away it should be something with the connection/communication with the MPU board and I'd look into the MPU board. If it won't go away and you still have issues there is something with the DMD controller board. Suggest looking closer at the 6809 microprocessor in that case. Best if you have an oscilloscope so you can have a look at the basics with the processor like stable power (at the processor pins), check so the reset pin has stable power and doesn't have power drops. With an oscilloscope it's easy to check the reset signal from the MPU as well.