Problems with classic games at arcade (bitrot?)

[Mr.FoodMonster]

I was at the local arcade the other day, and noticed that a few of the older games are kinda messed up. What I mean is, ok, in Donkey Kong, Mario, Princess, DK, and the barrels all have... extra blocks on them, I guess you can say. Like, the bottom of the barrel is all solid one color, but the top is fine. Top of DK is fine, but his feet are surrounded by solid color. Whats the problem here? Is this an example of Bitrot, and is there anyway to fix it? Just kinda intrested, is all.

[Cassidy Nolen]

Bad video RAM.

 

Cassidy

[Mr.FoodMonster]

How would one go about fixing this? Again, just for future reference. Would you need to replace the board (hell, do games like DK even HAVE removeable boards?)

[Pixellated Ghost]

How would one go about fixing this? Again, just for future reference. Would you need to replace the board (hell, do games like DK even HAVE removeable boards?)

 

As with any arcade machine, the logic board should be removable. To fix it you'd have to determine which ram chips were bad and replace them.

[Cassidy Nolen]

http://klov.com/game_detail.php?letter=&game_id=7610 and download the appropriate manual for your boardset. There were a few variations of DK IIRC, and then just trace down the player graphic RAM. I'd personally 'shotgun' repair a whole section (not very good at isolating which one is bad), but I would narrow down to the player graphics section first (no need to change background object RAM, its working fine).

 

Might even be some fixes recorded out on the web. There is a very well done site about which chip does what for Ms. Pac and some others.

 

Cassidy