Hello pinside, I need your help once more.

Last weekend we went and bought a working batman forever. It was in very nice condition, nice playfield, everything working, snappy flippers. About everything you need when buying a pinball machine.

However, today luck changed. A colleague turned the machine on, and instead of the normal display, it showed up all garbled like in the attached picture.

It was not blanking out or resetting or had any problems whatsoever before today, so something must have failed. I've tried reseating all connectors and ribbon cables without luck. What could it be?

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Alright, there's a few tips I can work with. I'm going to check tomorrow.

No, we did no ROM update ourselves, we have it barely over 2 days. There are stickers on the chips of the displays, so it might be ROMs that are not original, though it was working until today.

The game is playable, only the display is gibberish. The guy it was previously from just sent a mail, and he said it might have something to do with the square IC on the back of the display. It's probably not making good contact. Broken foot, thus not making contact somewhere perhaps. If that would be the case it would rule out the power problems, since the display is on, and not blanking/resetting. It still is a good idea to renew the connector and/or cabling though.

Well, I did some measurements just now:

4,88V at the connector on the DMD.
4,92V at the connector of the 5V supply.

I've also noted some blanking now regularly, that would mean that the garbled image blanks out for a fraction of a sec and comes back up again. It kind of contradicts what I stated yesterday, that I did not see blanking, but now I do.

How can a working display degrade so fast?

I get the feeling I'm dealing with both problems and we are just severely unlucky. (though, the pin is sweet looking)

The game was fine the one moment, then it was turned on and the display was scrambled.

These are the chips on the board of the display. They look 'custom', we did not put them in there. I might have to pull off the sticker to see the correct type, but I'm sure the correct ones are used, otherwise the display wouldn't have worked before. We might need to get other ones just to check.
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Today I also noted the display blanking out quickly, then restarting. Here's me measuring the connector.
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And yes, I noticed the links weren't working anymore, I was about to get to that but you were ahead of me.

The connector/wires are not a problem. But I don't think it would help much, as the voltage is only marginally higher when measured directly from the 5V power supply, and that is only 4,92V as stated before. My guess is that PSU components also need an upgrade (new capacitor / bridge rectifier), next to some juicier wires to the display.

Also, which chips would be the RAM?

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Well, I'm not sure about any ripple on the circuit, but my guess is that it's definitely a good idea to at least put in a fresh bridge rectifier and caps in the 5V circuit. Plus new cabling and connectors to the display.

I have the display at home now, as tomorrow we go visit the seller to pickup another pinball. He also has another batman and we can verify whether it is the power supply. I've noticed something else when measuring and checking some stuff on the DMD board.

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This is the power board directly under the DMD driver board. The diode (D7) in the middle measures conductivity in both ways. I've checked it with some other diodes elsewhere on the board, but they appear to be good. What's strange is the diode seems to be connected with the transformer for the high voltage (?). I'm not too sure about anything here, because I can't seem to find schematics of this pin at all. Of course the original manual/schematics are gone as well.

This diode seems important for the the display to be working, and it still does even with this thing failing.

Well just to give closure to this thread, the problem was found and solved. At the seller where we got a very fun Starship Troopers, we tried the display in the other batman. It performed just as worse. Then we tried bypassing the driver board, and connectes the display cable from the working DMD: bingo.

The problem was in the square chip socket, it was old and rounded and possibly wasn't making proper contact, causing the problems. The seller was cool and we got the working display.

It was even working in our own Batman Forever, no power problems.

Thanks for the help all!

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