Power supply problems are quite common on this machine and often affect the performance of the large dmd. Do you have the service bulletin that directs owners to a power supply update?
There is a harness that helps or alleviates power supply issues.
Pinball life almost always has them in stock.
Another common issue is the connectors and the large ribbon cable for the dmd.
If I don't play mine for awhile I have to reseat, reseat, reseat the "z"connector and ribbon cable, as well as the others.
These two suggestions often remedy dmd issues on this machine.
Start with these and let us know if anything helps.

Check the connector to the power board on the upper right. This machine ALWAYS has issues with that connector and the power supply in general.

I would definitely replace and repin the connector to the DMD, as rollitover said above. That’s commonly very flaky on all 6 large DMD Sega games. Even if that’s not your issue now, it will become an issue later making the display cut out totally during gameplay.

You don't have another SEGA game to make the swap and see if the display underperforms there, too?

Try posting in the
Batman Forever Club thread.
You might get more insight, opinions and suggestions.

I wish I knew more so I could help you further.
You might try researching this forum on anything to do with "dmd" or more specifically Sega large dmd.
There were a small number of machines made with the large dmd so you might investigate those Club threads if you haven't done so already.
Might be a bit time consuming but might be worth a try.

Can you take a video of it in the display test mode (row/column test) to give a better idea of what it's doing in action?

Thanks for the video. I was expecting the row test line to drop out at the halfway point where you lose the bottom half of the screen, thinking it was the IC that manages the rows on the display. But that doesn't happen. So, back to the drawing board.

Definitely wondering if it's one of the Display EEPROMs that is going bad. Do you have access to an EEPROM burner?

Also, can you take a nice-res picture of the DMD controller board on the back of the display (without the connectors, so it's a full picture) and upload that here with full res (click the dropdown box before uploading)...

Here’s mine if that helps at all. It looks like whoever had my game temporarily before I bought it back cracked the connector and put a tie around it. Thanks for making me look.

70C9AB32-2D20-4E5C-8A94-B9DB1C158778 (resized).jpeg91EEAE24-A8B5-41EA-B515-98370ADAB566 (resized).jpeg

Thanks, but I still would like to see the one on his machine (without the connectors, and with the board lined up to use all the resolution in the picture) in case something jumps out at me (suspect solder connection, etc).

I really am leaning toward an issue with the display ROMS, especially since the screen itself passes the row and column test fine.

Use the flash on your phone and brighten it up 'eh.
Flashlight even.

If you can edit that post and re-post that picture, but before you drag and drop it or pick it using the button, select "original size (no rescaling)" so pinside doesn't limit the resolution, that would help. The one you posted was resized to the default pinside medium res.

pinside res box (resized).jpg

The first one was better because the board was full-frame. So more like the first, but with flash or some extra lighting and pinside resize off when you upload should be perfect.

Looks like a burned capacitor at C9 (the little orangey yellow ones), right below ROM2 on the board. Possibly some other damage nearby. Still inspecting...

'atta boy
Btw
As a BF owner I am learning right along with you should it ever come up with mine.
Hope you get this resolved.

The schematic mentions capacitors on the back of the board, so those are probably factory. I think your problem is C9. I'd start by replacing that. Also the corrosion or fire or whatever happened to C9 looks like it might have damaged the corner of the U10 chip and the trace, plus some of the smaller traces that just ran under C9. I'd also check for continuity on that trace that runs up to the top of the board as well as those thinner traces that ran under C9.

If it's like all the others on the board like it, it's 470pf, but I can't find it on the schematic (the scans are crappy).

SEGA Large Display 1 (resized).jpgSEGA Large Display 2 (resized).jpgSEGA Large Display 3 (resized).jpg

Looking at that damage, I really doubt it's the EEPROMS now. I would get some socket rows and that chip at U10 as well so you can replace it if replacing C9 and cleaning up that area doesn't fix it.

Have you unsoldered ICs before? If not, I recommend carefully clipping the legs off then unsoldering one leg at a time. Very easy to lift a trace and make more work for yourself. Do NOT overheat the pads. Add new solder to loosen old solder.

Definitely post how it turns out, there may be other components along that trace besides the chip that were also compromised.

I'll chime in on that point. This one has some really cool features and shots that is for sure.
Looking forward to your next update.

You might want to consider this service kit for the display if it's not already done. Prevents freezing and resets on the display due to power dropping below 5v while in use:

https://www.marcospecialties.com/control/keywordsearch?SEARCH_STRING=500-6326-00

Service bulletin is on that marco page, too.

Did you check continuity on all those little traces that ran under C9 (from wherever they started to wherever they end)? They may have been damaged when C9 blew out. I'd do that while you're waiting for the IC.

I need to find a schematic with that C9 on it to see what else is in line with it on the +trace. The one I posted doesn't have that part on at all that I can see. Can you see where the positive trace goes when it goes under the ROM2 bracket and disappears?

Great news! It will be interesting to see if it's the display.

That is good news.
Get closer to the problem that's for sure.

If anything falls through with that, let me know. I could always send you the one out of my BF for testing.