Mortal Kombat 2 - locks up - weird alarm noise - static on screen - mk2

likwidtek

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Mortal Kombat 2 - locks up - weird alarm noise - static on screen - mk2

So, I got an mk2 cabinet a while back, played fine but needed new sticks.

Finally I got to replacing the second stick today but while I was in there I figure I'd flip dip switch 2 - 2 3 & 4 for free play and replace the battery since it seemed to need one. Now I read somewhere I could just use any motherboard 3V battery and it would be fine so I took one from an old motherboard (even though it was smaller) and placed it in.

Now stupid me for making 3 changes all at once. New sticks, new battery, dipswitch changes.

When I fired it up, it seemed fine... it went right into play mode when I hit player 1, but then it locked up and if you got close to the speaker you hear a very slight tone that alternates high - low - high - low - high - low.

I immediately figure the battery is incompatible and take it out, plug the old one back in. I made sure to ground myself so I'm confident I didn't zap something. I fire it back up and it's doing the same thing. If I let it run the ROM tests, everything comes up green. It just locks up, screen gets fuzzy and that's it. :/ I was able to get it in test mode to make sure all the buttons are working. The player 1 coin was acting funny... it was getting jammed, so I thought maybe that was freaking something out, so I disconnected the wires to it (I think) to see if something was shorting out.

I don't know. I'm kind of stuck. Is there anything you guys could point me to to troubleshoot this. I'm really new to this kinda stuff.
 
pull the battery and put in the correct one. I'll try and find the post with the correct battery type in a minute.
 
I already put the original battery back in it and it's still giving me problems.. As far as I'm aware the game should work just fine even with a bad battery in it. It'll simply lose cmos settings if you unplug it. right?
 
correct, but i believe it might lock up or do something weird after a bit also, can't remember.

check to make sure all of your chips are fully socketed same with all your connectors (soundboard and edge).

did you flip the dips back and forth also a couple times (the ones you changed initially?) as they can cause some issues once in a while.


BR2325 is the battery you should have or will need to get
 
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correct, but i believe it might lock up or do something weird after a bit also, can't remember.

check to make sure all of your chips are fully socketed same with all your connectors (soundboard and edge).

did you flip the dips back and forth also a couple times (the ones you changed initially?) as they can cause some issues once in a while.


CR2032 is the battery you should have or will need to get

OK so I checked as many connections as possible. I didn't reseat anything but I just pushed on things and made sure everything was snug. I did flip the switches that I hit on and off again a few times like you said. When I powered the machine on it actually played the demo for a few minutes. Maybe 5 or 10. I played a couple rounds and left it to go back to the demo.

Maybe 10 minutes or so after it locked up again. It still has the old battery in it.
 
you don't even need a battery in there for the game to work.

Did you check what your +5 is set at? make sure it's at like 5.10 and re-seat all the socketed roms.
 
you don't even need a battery in there for the game to work.

Did you check what your +5 is set at? make sure it's at like 5.10 and re-seat all the socketed roms.

Do you you mean to check my voltages or something? Not sure how to do that. I can reseat the roms though. Which ones should I reseat though?

Is there already something out there that I haven't found that I could read to get me through the basic troubleshooting stuff?

I really really appreciate the help so far.
 
Re-seating roms really does work with these boards. I usually re-seat all the socketed roms on the board.

To check your +5 you need a multi meter. You got one? If you do you put the black probe on any ground somewhere and the red probe on one of the +5 pins on the pcb edge connector while it's powered on.
 
Are the ROMS just the 2 game roms or are there more?

Just pull them out with my fingers? Is there a trick to it?
 
did you set the dips back to where they were originally also?

you can check your voltages with a volt meter while the machine is on (BE CAREFUL THO!) black lead to your power supply/edge connector ground, and red to the +5/-5/+12v pads of the board.

mecha has a decent write up here: http://www.organizedmassconfusion.org/williamsmidway-y-unitt-unit-mknba-jamothers-guide/

I'm sure he'll chime in on this sometime tonight and lead you in the right direction (i only currently have NBA Jam boards and UMK3 should have my mk2's this week tho).

also reseating the roms will only help if they are coming up bad on the test menu. although some dust could be causing the issue or maybe if once the board warms up the connections are moving around a lil.... to pull the chips you need a small flathead screwdriver and use a seesaw motion on each side of the chip making note of the notch in the chip when you reinstall it. u can clean up the legs of the chip with fine grit sand paper (be gentile you just need to get the metal shiny again).

Unless you have a single board unit (no memory expansion board and soldered in chips), in that case i'd look for bad solder joints which is never fun. as the chips cannot be removed.
 
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did you set the dips back to where they were originally also?

you can check your voltages with a volt meter while the machine is on (BE CAREFUL THO!) black lead to your power supply/edge connector ground, and red to the +5/-5/+12v pads of the board.

mecha has a decent write up here: http://www.organizedmassconfusion.org/williamsmidway-y-unitt-unit-mknba-jamothers-guide/

I'm sure he'll chime in on this sometime tonight and lead you in the right direction (i only currently have NBA Jam boards and UMK3 should have my mk2's this week tho).

also reseating the roms will only help if they are coming up bad on the test menu.


I did set the switches back to all off which was the position that I got the machine in. I'll check out the write up. thanks.

And yes, all roms test green.
 
i edited that post, check it out again, added a bit after the reseating of the roms.
 
Broods you're slacking, you forgot to tell him to pull the game roms and sand the chip legs. :p

the secret to removing roms is to get a small but decent sized flathead that you can fit between the IC and the socket, and give it a little twist to just break it free (don't pull it entirely out yet) and alternate to the other side and do it again. if you did it right, you should be able to pull it out with your fingers the rest of the way. if not, stick the screwdriver back in and be very gentle. the chip legs bend very easily, and if you don't pull them out evenly, you'll have a bunch of bent legs.

inspect the chip legs for any corrosion. my MK2 checked out 100% on the rom checks and still gave me a SHITLOAD of issues, particularly with it locking up, playing crying baby sounds over and over, resetting, etc. periodically it would also throw up the Custom Chip Bad UE13 error... however, there was nothing wrong with the UE13, it was a communication problem with the 2 game roms, I think they're UG12 and UJ12 right? because of the corrosion on the chip legs. some fine sandpaper, taking extra care not to snag the legs or bend them, until they're silver and shiny again, brushed the particle shit off, and reinserting back in and voila! I run that game daily now.

the secret to putting roms back in is to make note of the U-shaped notches on the socket and chip, you want them to face the same way. you also want to make sure ALL the legs line up with the socket holes before you go crazy with seating them back in. your board must have mounting feet, the plastic white things the screws go through, on a T-unit board such as this one, without them and laying it on a flat surface, you're bound to bend some pins on the underside, often times they will touch together. you don't want that to happen! I generally throw some bubblewrap underneath if I'm doing a rom reseating job, line up the chip, and take your two thumbs and press it firmly flat. done.

since you're having some pretty bad issues, it wouldn't be a bad idea to inspect all the pins underneath to see if any are touching each other. if you have a PRECISION flathead, you can hook underneath any bent pins and straighten them back up. I haven't heard any stories about components getting permanently damaged if this occurs. but make sure you got mounting feet, otherwise if you set the board on a table or something, you'll just bend the pins flat again.

try what I said first, and report back. good luck!
 
Broods you're slacking, you forgot to tell him to pull the game roms and sand the chip legs. :p

the secret to removing roms is to get a small but decent sized flathead that you can fit between the IC and the socket, and give it a little twist to just break it free (don't pull it entirely out yet) and alternate to the other side and do it again. if you did it right, you should be able to pull it out with your fingers the rest of the way. if not, stick the screwdriver back in and be very gentle. the chip legs bend very easily, and if you don't pull them out evenly, you'll have a bunch of bent legs.

inspect the chip legs for any corrosion. my MK2 checked out 100% on the rom checks and still gave me a SHITLOAD of issues, particularly with it locking up, playing crying baby sounds over and over, resetting, etc. periodically it would also throw up the Custom Chip Bad UE13 error... however, there was nothing wrong with the UE13, it was a communication problem with the 2 game roms, I think they're UG12 and UJ12 right? because of the corrosion on the chip legs. some fine sandpaper, taking extra care not to snag the legs or bend them, until they're silver and shiny again, brushed the particle shit off, and reinserting back in and voila! I run that game daily now.

the secret to putting roms back in is to make note of the U-shaped notches on the socket and chip, you want them to face the same way. you also want to make sure ALL the legs line up with the socket holes before you go crazy with seating them back in. your board must have mounting feet, the plastic white things the screws go through, on a T-unit board such as this one, without them and laying it on a flat surface, you're bound to bend some pins on the underside, often times they will touch together. you don't want that to happen! I generally throw some bubblewrap underneath if I'm doing a rom reseating job, line up the chip, and take your two thumbs and press it firmly flat. done.

since you're having some pretty bad issues, it wouldn't be a bad idea to inspect all the pins underneath to see if any are touching each other. if you have a PRECISION flathead, you can hook underneath any bent pins and straighten them back up. I haven't heard any stories about components getting permanently damaged if this occurs. but make sure you got mounting feet, otherwise if you set the board on a table or something, you'll just bend the pins flat again.

try what I said first, and report back. good luck!

nah not at all, it's in the edit :D

i knew you'd superman in to the rescue here ;0)
 
Thanks guys. I'll try the ROM thing this week. I have to pick up a multimeter that works. Mine needs new batteries but I need a new one anyway.

I'll post back when I know more.
 
lock up

Odds are if it locks up or resets it is a voltage problem either caused by the power supply getting weak or the edge connector where the voltage connects.
If it is dark around the edge connector voltage pins area, then i would solder wires directly.
Always be careful on turning voltage up if a power supply is weak as sometimes the caps, etc... in the power supply can go back to good and cause the power supply to put out a higher voltage again which could hurt the board. Do it once or twice then replace the supply.
Those boards do suck up some amps from those switchers, which weakens them faster then other games.
 
I think I had a part in my writeup about edge connectors getting dirty. you just use a pencil eraser on the JAMMA edge, and you'll be surprised at how clean it gets the contacts. with all the dirt and crud on them, naturally it will cause poor or intermittent contact with the power wiring, if voltage drops low enough it'll be almost as if you cut power to the game, which is what causes the resets.

if you clean with the eraser, just make sure you brush the eraser shavings off the board. ideally erase, then rub the contact away with your finger on each one.
 
I think I had a part in my writeup about edge connectors getting dirty. you just use a pencil eraser on the JAMMA edge, and you'll be surprised at how clean it gets the contacts. with all the dirt and crud on them, naturally it will cause poor or intermittent contact with the power wiring, if voltage drops low enough it'll be almost as if you cut power to the game, which is what causes the resets.

if you clean with the eraser, just make sure you brush the eraser shavings off the board. ideally erase, then rub the contact away with your finger on each one.

+1 to the eraser method, learned this when i was about 8 or 10 when my Train set wouldn't work that well.
 
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