(Topic ID: 240238)

DMD Displays Extra Lines


By JohnJN

6 months ago



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  • 16 posts
  • 3 Pinsiders participating
  • Latest reply 6 months ago by JohnJN
  • Topic is favorited by 1 Pinsider

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#1 6 months ago

Hi All,

I'm attempting to troubleshoot an issue with the DMD display on my JP -- throughout play it seems to display certain lines as active that shouldn't be. It doesn't affect gameplay but visually doesn't look nice.

Is this a common issue? any suggestions for fix?

The roms in the game are quite old (Display V4.00 / CPU 4.04) and will be installing v6 roms very shortly.

Screen Shot 2019-04-07 at 2.34.50 PM (resized).png
#3 6 months ago

Your JP has a plasma display. The Tron has a LED display, which is a different design. I don't think this is a DMD issue in your game. Looks more like a RAM problem, but not sure if the DMD controller has one there.

#4 6 months ago
Quoted from PinballManiac40:

Your JP has a plasma display. The Tron has a LED display, which is a different design. I don't think this is a DMD issue in your game. Looks more like a RAM problem, but not sure if the DMD controller has one there.

Thanks @pinballmaniac40 - I will research further.

#5 6 months ago

If it's only a partial line I'd also go with a RAM problem. Try swapping the DMD to a different game to verify it's not on the DMD board but an issue with the RAM on the DMD driver board.

#6 6 months ago

Found it. It is on the DMD controller board at U8 location. Likely it is soldered in, not in an IC socket. The manual shows it as a 62256 RAM, but need to check the actual part to make sure.

#7 6 months ago
Quoted from kbliznick:

If it's only a partial line I'd also go with a RAM problem. Try swapping the DMD to a different game to verify it's not on the DMD board but an issue with the RAM on the DMD driver board.

kbliznick -- sadly this is my one and only pin, I'm new to the hobby so I'm not able to swap DMD's into another machine just yet.

Quoted from PinballManiac40:

Found it. It is on the DMD controller board at U8 location. Likely it is soldered in, not in an IC socket. The manual shows it as a 62256 RAM, but need to check the actual part to make sure.

pinballmaniac40 -- Thanks, I will open up the game and check it -- But I've googled '62256 RAM' but only NVRAM seems to come up on Marcospecialties -- would this chip work for a DMD controller board?

#8 6 months ago

It may but would be overkill since the regular RAM would likely be $10 cheaper. I will try and look on the internet tomorrow.

Other manufacturers used 6264 RAM, but not sure if it could with a jumper change, on this board, assuming one exists.

#9 6 months ago
Quoted from PinballManiac40:

It may but would be overkill since the regular RAM would likely be $10 cheaper. I will try and look on the internet tomorrow.
Other manufacturers used 6264 RAM, but not sure if it could with a jumper change, on this board, assuming one exists.

I found ones listed on eBay, but it seemed like variations with different end lettering to the ram designation.

#10 6 months ago

You have to watch if these come from China. You don't want a counterfeit part. You will definitely want to use an IC socket once the old one is out.

#11 6 months ago
Quoted from PinballManiac40:

You have to watch if these come from China. You don't want a counterfeit part. You will definitely want to use an IC socket once the old one is out.

Hmm - that sounds like a great plan, however completely out of my skill set unfortunately -- I've never soldered anything before let a lot reset a socket unfortunately.

#12 6 months ago

No problem. Chrishibler will be happy to help.

#13 6 months ago
Quoted from PinballManiac40:

No problem. Chrishibler will be happy to help.

Damn man - I think I owe you at least a round or two, thanks for all the help!

#14 6 months ago

No worries. It is what I do. Wish I wasn't behind on my own projects, otherwise I would repair it for you.

#15 6 months ago

Here is something you can do. This is plug and play (for all DE, Sega and Stern Whitestar games) and no soldering required for your JP game. NVRAM will eliminate batteries out of your game.

https://www.pinitech.com/products/6264_nvram.php

#16 6 months ago
Quoted from PinballManiac40:

Here is something you can do. This is plug and play (for all DE, Sega and Stern Whitestar games) and no soldering required for your JP game. NVRAM will eliminate batteries out of your game.
https://www.pinitech.com/products/6264_nvram.php

Ordered! Thanks man!

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