TECH: DE game--checkered egg on DMD

stevenp61

New member
Joined
Jun 24, 2009
Messages
1,040
Reaction score
5
Location
Florida
{Searching on this proved fruitless]

Does anyone know what it means if the display on a Data East game (midgame) suddenly shows what looks like an egg covered with a checkerboard pattern, and a checkmark (maybe a period also) over the egg? It is a static image that stays on the DMD even though the game continues to play normally. A power cycle fixes things; not sure how frequent but happened twice in 4-5 games.

Could this have something to do with a bad SRAM chip? (Which I already know about)
 
OK, got another "egg display" mid-game. This was a plain egg with what looks like a bug/spider on it, game still ran normally, needed a power cycle to reset the display and get the graphics working properly.

Has *anybody* seen this on a DE game? Could it be display ROM, the (bad) SRAM chip, something else? (I reseated all cables/connectors from main board to display controller to DMD.)
 
I've got nothing, but could you by any chance get a picture of it when it happens? I don't know if it would help, but it may not hurt for us to be able to see what is going on.
 
Maybe update the ROMs? Or do a factory reset?

Also, what mysterious game is this of which we speak?

Sorry, it's Royal Rumble. ROMs are latest versions (1.06 and 1.02 for the display). factory reset didn't help, but problem is sporadic. (It can go a few games without any problem.)

I'm suspecting (after some more research) it may be a bad connector/cable somewhere. PITA to troubleshoot tho. I reseated all cables (power supply board, CPU board, display driver board). Display board is getting 5.1 V, which seems OK. Waiting for a new SRAM chip to arrive--dunno if that would be the problem tho.
 
i have royal rumble. during game play at different times i will get the egg you speak of. the difference with mine is the egg cracks open and a bonus shows on the dmd. like when you score 3 skill shots in a row.
 
i have royal rumble. during game play at different times i will get the egg you speak of. the difference with mine is the egg cracks open and a bonus shows on the dmd. like when you score 3 skill shots in a row.

This further bolsters the ROM possibility. Are the ROMs in your game factory? If not, I would strongly suggest verifying them with a burner, as if this DMD animation is corrupted it could cause the lock-up you describe. I'd guess it's the display ROMs that are having the issue.

Edit... Even if they are factory, still test them with a burner against the original images from DE/Sega/Stern.
 
This further bolsters the ROM possibility. Are the ROMs in your game factory? If not, I would strongly suggest verifying them with a burner, as if this DMD animation is corrupted it could cause the lock-up you describe. I'd guess it's the display ROMs that are having the issue.

Edit... Even if they are factory, still test them with a burner against the original images from DE/Sega/Stern.

hmmmm... thx for the suggestion. The ROMs are updated ones, not original. I will either check them (don't know anyone local with a ROM burner) or maybe get replacements. Would the likely culprit be the game ROM or the display ROM?

UPDATE: Another bit of info--I noticed that when the egg came up a couple of times, it sometimes would stay for 5-10 seconds, then a screen shows for a second or 2 with the display rom versio (1.02, same message that shows on startup), and then the display goes back to regular game video display.

So, flaky display rom? or maybe a power glitch? Sometimes the egg seems to show up when flashers start up, b ut that may be my imagination or a coincidence. (Flashers appear a lot in this game, and the backbox flashers are all LEDs with lower current draw.)
 
Last edited:
This further bolsters the ROM possibility. Are the ROMs in your game factory? If not, I would strongly suggest verifying them with a burner, as if this DMD animation is corrupted it could cause the lock-up you describe. I'd guess it's the display ROMs that are having the issue.

Edit... Even if they are factory, still test them with a burner against the original images from DE/Sega/Stern.

Problem seems to be solved with a new dsplay rom. (Cheaper/quicker than trying to verify it.) And the sporadic failure to start up with the display going blank was traced to a flaky connection of the DMD board-cpu board ribbon cable at the top of the cpu board. All is well now!
 
Back
Top Bottom