Mortal Kombat II 2 Problem booting.

titomysta3000

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I am Having trouble getting my MKII Pcb to work.
I turn on my machine and goes through the test mode and fails alot of the chips.
Has any one had this problem or know how to fix it?

2012-06-07_01-00-09_593.jpg



Once it goes through the entire test if i hit a button or not do anything i hear the sound (bell or ding) and midway tries to load up but the image is messed up then it resets.


2012-06-07_00-59-32_885.jpg


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I would love to get it up and running and am hoping its an easy fix.

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Pics attached
 
I checked the voltage and it seems fine around 5.03 now how do i reset the chips?
 
I checked the voltage and it seems fine around 5.03 now how do i reset the chips?

That might be a little low. Did you check it at the PS or at the harness with the game plugged in? I thought they ran about 5.2v but am not 100% sure. Broodwich, chime in on this!
 
I checked the voltage and it seems fine around 5.03 now how do i reset the chips?

Usually you pull out the rom chips and inspect the legs for any problems then put that chip back in the socket it came from and repeat for all other socket-ed chips. If you have not done this before I would just put something sturdy under the board, like a book, and press down on all of the socket-ed chips. If you are new at removing and replacing the chips you can bend and break legs and cause more problems.

EDIT:

I would check the voltage on the battery on that board also as that can cause problems also.
 
Check to solder side of the board for socket feet that are bent over touching each other. There should be NONE. I have repaired numerous boards that way. Sometimes when people store the boards or press down on them to seat roms, they bend the socket feet over and cause them to touch each other which causes all types of issues. That being said, removing and reinstalling the roms works wonders. Just make sure you install them back the correct way because if you install them backwards, you're creating more problems.

That's my recommendation.
 
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Alright thanks guys i will remove and put back the chips 1 by one, higher the voltage little by little and see if that fixes my problem.
 
removed the chips in red sanded down the legs to clean em and set them back. also played with the volts and hired it little by little but still resets even when giving it full power. I checked the back and it seems like none of the solder is touching each other creating shorts or bad connections.

I have no idea what could be causing this..... I do have a UMK3 board is it possible to test MKII on that swap out the roms? I doubt that all those roms are bad...
 
Check to solder side of the board for socket feet that are bent over touching each other. There should be NONE. I have repaired numerous boards that way. Sometimes when people store the boards or press down on them to seat roms, they bend the socket feet over and cause them to touch each other which causes all types of issues. That being said, removing and reinstalling the roms works wonders. Just make sure you install them back the correct way because if you install them backwards, you're creating more problems.

That's my recommendation.

yup this would be my first check

removed the chips in red sanded down the legs to clean em and set them back. also played with the volts and hired it little by little but still resets even when giving it full power. I checked the back and it seems like none of the solder is touching each other creating shorts or bad connections.

I have no idea what could be causing this..... I do have a UMK3 board is it possible to test MKII on that swap out the roms? I doubt that all those roms are bad...

yup another great spot to go from. but normally this would only cause one or a couple chips to fail.


remember to check your voltages at a chip not at the edge connector. as it's a far more reliable spot to check from.

also try pushing on different sections of the board, and squeezing the 2 boards together where they connect to each other on the side there (if this fixes your issue you mostlikely have a bad solder joint at one of those headers.

my money is going with bent over/touching pins tho, but it also wouldn't surprise me if the board is actually seeing low voltage at the chips either.

Here's a pic of what pins to meter for 5v adjustment thanks to Mecha (Note the notch/key location on the chip).

attachment.php


and here's the difference between a clean and dirty edge connector (use a pencil eraser to clean these, make sure to keep all shavings off the board) by lightly sanding the legs of your chips you will accomplish the same thing (you might also find a dust bunny or small spiders nest under one as well).

*see image 2

removed the chips in red sanded down the legs to clean em and set them back. also played with the volts and hired it little by little but still resets even when giving it full power. I checked the back and it seems like none of the solder is touching each other creating shorts or bad connections


I have no idea what could be causing this..... I do have a UMK3 board is it possible to test MKII on that swap out the roms? I doubt that all those roms are bad...


Unfortunately you can't swap the roms from a later mk into a earlier or visa versa, you can however remove the smaller memory expansion board and try booting it without that to see if the lower chips will come up green, if so then the issue is mostlikely with the expansion board but if not then it's the main board that has an issue.

are there any visible scratches across any section of the solder side of the main board?
 

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Something else to consider. I was trying to repair an MK1 T-Unit (same as your MK2), because it was resetting on me. I pressed on the large graphics chip in the middle of the board and bam! It started working. I removed and reseated it and haven't had a problem since. I really don't think that would cause your issue, but it's something to look at.

My money's still on the socket feet on the bottom of the board touching wach other somewhere because the likelihood of ALL your roms being bad, including the ones on the memory expansion board being bad is extremely UN-likely.

On a side note, here is an example of how the wrong voltage can cause an MK board to reset. MK1 and MK2 are VERY picky about their voltages...


 
I checked the back and it seems like none of the solder is touching each other creating shorts or bad connections.


Are you referring to the solder pads/runs? I was referring to the socket feet tabs. Is that what you checked?

Something else to consider - an open trace. Look for open traces on the solder side (bottom) of the board. It's possible that at sometime in the past, this board was stacked on top of another and was scratched up creating an open traces(s). I have seen boards with the mounting screws still in them stacked on top of other boards which is a problem waiting to happen. Give the whole bottom side a good look over for any possible open traces (circuit pathways).
 
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Something else to consider. I was trying to repair an MK1 T-Unit (same as your MK2), because it was resetting on me. I pressed on the large graphics chip in the middle of the board and bam! It started working. I removed and reseated it and haven't had a problem since. I really don't think that would cause your issue, but it's something to look at.

My money's still on the socket feet on the bottom of the board touching wach other somewhere because the likelihood of ALL your roms being bad, including the ones on the memory expansion board being bad is extremely UN-likely.

On a side note, here is an example of how the wrong voltage can cause an MK board to reset. MK1 and MK2 are VERY picky about their voltages...



I'm surprised you never fried any chips at +5.9v, some TTLs will fry after +5.25v.
 
I'm surprised you never fried any chips at +5.9v, some TTLs will fry after +5.25v.

Yeah, but I was testing directly at the power supply when I should have been testing at the chips. The voltage was more likely at the 5.25 range at the chips themselves.
 
Yeah, but I was testing directly at the power supply when I should have been testing at the chips. The voltage was more likely at the 5.25 range at the chips themselves.

that's a pretty dirty edge connector to lose that much power lol.

I'm particularly confused as to how both the main board roms and the memory expansion roms are all showing red. what I have below doesn't really pertain to your problem cause I have no idea why this would happen.

I repaired a single board MK2 that had a rom error by throwing known-working NBA Jam roms in it and it generated rom errors on the same socket plus the one next to it. by doing this I discovered that it was the adjacent rom socket that was causing the issue, running continuity checks between each pin I found one dead and jumpered it to fix it.

the other way to generate entire red rom errors is to have your board jumpered for the wrong type of roms, it will either work with 4 mb roms + the memory expansion or 8 mb roms and no memory expansion.

you're looking at a very obvious hardware error here somewhere. does your board have any noticeable flexing? like someone could've bent the board. you want to look for any obvious gunk anywhere, broken traces, and touching component legs. the T-units had ridiculously long component legs and it's very common for them to get bent, and often times you won't even notice it the first 5 times you look the board over.

the voltage test instructions that Broodwich included are also entirely necessary. I would think that the game roms would show errors too if it was a voltage thing though.
 
that's a pretty dirty edge connector to lose that much power lol.

I'm particularly confused as to how both the main board roms and the memory expansion roms are all showing red. what I have below doesn't really pertain to your problem cause I have no idea why this would happen.

I repaired a single board MK2 that had a rom error by throwing known-working NBA Jam roms in it and it generated rom errors on the same socket plus the one next to it. by doing this I discovered that it was the adjacent rom socket that was causing the issue, running continuity checks between each pin I found one dead and jumpered it to fix it.

the other way to generate entire red rom errors is to have your board jumpered for the wrong type of roms, it will either work with 4 mb roms + the memory expansion or 8 mb roms and no memory expansion.

you're looking at a very obvious hardware error here somewhere. does your board have any noticeable flexing? like someone could've bent the board. you want to look for any obvious gunk anywhere, broken traces, and touching component legs. the T-units had ridiculously long component legs and it's very common for them to get bent, and often times you won't even notice it the first 5 times you look the board over.

the voltage test instructions that Broodwich included are also entirely necessary. I would think that the game roms would show errors too if it was a voltage thing though.

Ill look to see if the board is bent. I started checking for bent legs touching but haven't spotted any and my eyes hurt :/ ill recheck later today if i have time. Also i didn't notice any gunk on the board but ill check again. I will be checking for the chips for voltage and continuity like pictured in the first page but i have misplaced my multimeter somewhere and can't seem to find it.
 
FYI, the game resets because the roms clearly aren't working properly if every single one of them is showing bad. the board I was fixing would do this with 1 rom showing bad, or the entire game would be scrambled lol

the only other thing I could think of is that someone removed all the roms and put them back in wrong, which if they don't have labels, the only way to check them is to compare checksums of each rom against the roms in the MAME 'mk2' rom set.
 
i have a mk2 that does this on bootup.

http://www.youtube.com/watch?v=JBIC5THjPaM

not a voltage issue though as i have another set that works on the same cabinet.

i'll have to look into it. the suggestions here are all good.

Looks like you have a ram or a processor issue. As soon as it gets to whatever ram/chip check that is off screen, it resets. Hmmm.....
 
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