MORTAL KOMBAT 2 Memory not working correctly

Angelo

New member
Joined
Feb 16, 2014
Messages
1
Reaction score
0
Location
Vancouver, BC, Canada
Hello All,

I just picked up a MK2 (rev 3.1). When I turn it on, it gives me a error message: "CMOS chip U49 bad. Unable to restore factory settings."
Normally I thought it would just be the battery, but with a new battery installed (or even with none installed) I have the same problem. I think the U49 or another chip is bad. This is because everything in the memory is messed up.

All memory seems to have been maxed out. When I turn it on, it says there are 255 65,535 credits! Plus also all the audits are maxed and it displays a error message too, see link attached photos:


https://imgur.com/gallery/L1jWO


Any help is greatly appreciated!

Thanks!
 
Pretty sure the ue13 in the center of the board needs a reflow. Never had it on an mk2 but with the same hardware for MK 1 I had the same issue. Try pushing down on that chip when booting see if it changes.
 
okay, I never really delved into this because I don't recall it happening to me before. we have almost every Midway game from this era at the shop, so maybe so.

the U49 CMOS chip is apparently only powered by the CMOS battery. if you look in my PSU guide for how to measure voltage at chips, I would gather the + for the battery runs to where +5 goes in my picture, and - to the ground pin. put a fresh battery in and measure voltage like that, see if your battery voltage is present there. I'm pissing in the wind cause I'm at home now and would have to tear apart my Multi Kombat and also pull the tools out of my car to do it here.

if for some reason the voltage isn't present, then you need to look over your battery holder. does it have rust or corrosion in it? if so you'll need to replace the holder. not sure where you can source a replacement for a CR2325 holder.

if you're getting voltage there, then you need to get into test mode. if you're unable to get there with the test button in the coin door, you can turn dipswitch bank UJ2, switch 8 to ON and dipswitch bank UJ1, switch 7 to ON to disable the power-on self test. the game will thus immediately boot into test mode. next try going into Utilities -> Full Factory Restore. power cycle the game with your healthy battery feeding voltage to U49 and see what happens then.

I ran a search here for "cmos u49" and I'm gathering it's uncommon for the chip to fail, it's mostly going to be a problem with the battery.

good luck
 
Back
Top Bottom