Weird UMK3 security chip on original midway board.

Joined
Jan 26, 2019
Posts
16
Greetings to all of you.This is my first post on these fora,and i hope i can use your technical knowledge on the subject.

Before 2 years i bought a ultimate mortal kombat 3 jamma pcb.For all intends and purposes the board seems legit and original midway board.It also plays well except from a bios error that you can see in the photos.

Instead of a regular security chip,this board has in place a different one that seems user made.It has an unknown IC (unknown by me and different from the regular i see on the internet) combined with a resistor.

The question is : Did someone broke the protection ic code and reverse engineered it?And if so why?
The rest of the board is original,as far as i know the only purpose this can serve is if it was a different game and converted to UMK3 and they didnt have the security chip.But the roms and the stickers on the roms seem right.

Below are the images on a google photos folder.

https://photos.app.goo.gl/tnisCYHxsQ1un4qq5
 

SpamYouToDeath

I asked for a, Custom Rank and, Learned My Lesson.
15 Year Member
Joined
Oct 3, 2005
Posts
6,059
The MAME source code claims that U64 is the "security PIC (provides game ID code and serial number)". The UMK3 ROMset from MAME contains a dump of this chip. So anyone could make a replacement by buying a compatible PIC and burning it.

Maybe the board is a conversion from regular MK3? I don't know how different the EPROM labels would look.
 
Joined
Jan 26, 2019
Posts
16
Indeed the board can be a mk3 to umk3 conversion.The corresponding roms for that seem to be eproms and not original.I didnt know someone could copy a security IC and replace it with another one from commonly available parts.Also i am doubting the knowledge of someone doing it in the past 10-15 years because internet usage was not widely available till 2002 and something like that would require both knowledge of mame dumps,and burning ic's and i think we didnt have many so technical savvy people here at this time.
Anyway thanks for the reply!
 

Kid Panda

The Chinese Kid
Joined
Jun 13, 2010
Posts
12,514
Indeed the board can be a mk3 to umk3 conversion.The corresponding roms for that seem to be eproms and not original.I didnt know someone could copy a security IC and replace it with another one from commonly available parts.Also i am doubting the knowledge of someone doing it in the past 10-15 years because internet usage was not widely available till 2002 and something like that would require both knowledge of mame dumps,and burning ic's and i think we didnt have many so technical savvy people here at this time.
Anyway thanks for the reply!

There's alot of backside info available on newsgroups, arcade ops had been sharing this stuff for awhile. So while the info wasn't on the internet, it was online for many years.
 

Shuri

Kula's Candy
10 Year Member
Joined
Jul 2, 2012
Posts
294
I remember that there was a guy on KLOV that was able to do something similar a few years ago with MK3 type boards. He was able to convert any of those games into another.

I can't really search right now, but it's somewhere on the klov forums. Maybe it's a board that was modified by him?
 

mr_b

Windjammers Wonder
10 Year Member
Joined
Jun 1, 2009
Posts
1,379
UMK3 was a free upgrade for arcade ops that bought MK3 boards. The arcade I worked at during that time just had to contact Midway to verify purchase. It was even notated in magazines at the time before it dropped. That's why its so rare to find an mk3 board outright.
 
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