Frustrated with Mortal Kombat II

Zoma

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I'm still fairly new to repair and I've read that MKs can be picky, but I didn't realize it would be this frustrating. I've been having a few issues with a Mortal Kombat II I recently acquired. The game itself ran perfectly (with no sound) for a few days until this randomly started happening:
http://i.imgur.com/H5CVo.jpg

This is what the rom check settings says. I can't even make it out. If someone could translate what this means please do.
http://i.imgur.com/gOTfm.jpg

Just for kicks we took the second board off the main MKII board and the problem went away. Of course, the game itself didn't run, but at this point I'm thinking I should try cleaning + reseating the ROM chips, but I'd like other possible solutions aside from that so I can sit and try everything tomorrow when I get there. Here's a screen of what it looked like when we booted it up with no second board:
http://i.imgur.com/LiAoY.jpg

It looked like some of the pins might've been bent on the second board, but they still went into the connector just fine. Any idea if this might be causing my problem?
http://i.imgur.com/Tcxzu.jpg

Thank you guys in advance.
 
The memory expansion board should have nothing to do with ram errors. I can see that the red items are ram chips and not rom chips. Even with the expansion board removed, the only difference should be that those roms will be red.

My advice would be to re-seat the PLCC socket-ed graphics chips. (UF5/UB21) I'd also make sure that there is no dirt/debris around the UE13 processor.

Also, turn the board over and inspect it for bent socket feet that are touching each other. Look over the entire solder side of the board. Those can cause all kinds of issues.

Make sure you have EXACTLY 5vdc at the board. These boards are VERY picky.
 
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The memory expansion board should have nothing to do with ram errors. I can see that the red items are ram chips and not rom chips. Even with the expansion board removed, the only difference should be that those roms will be red.

My advice would be to re-seat the PLCC socket-ed graphics chips. (UF5/UB21) I'd also make sure that there is no dirt/debris around the UE13 processor.

Also, turn the board over and inspect it for bent socket feet that are touching each other. Look over the entire solder side of the board. Those can cause all kinds of issues.

Make sure you have EXACTLY 5vdc at the board. These boards are VERY picky.
Alright, I'll try all this tomorrow! Thank you for the tips.
 
Alright, I'll try all this tomorrow! Thank you for the tips.

You're welcome. Let me know how it turns out. Although, if you say the errors go away when you remove the expansion board, then re-seating the roms and fixing the pins might solve your issue too.
 
You're welcome. Let me know how it turns out. Although, if you say the errors go away when you remove the expansion board, then re-seating the roms and fixing the pins might solve your issue too.
While I've got you, I was also having an error with the sound board. I checked the voltage and made sure I was getting -5V DC to the thing and for some reason the sound board would power on during the rom check, but the light would immediately turn off as soon as it finished. Whenever I'd do a test I would hear 0 beeps, so I assumed this was a power issue and swapped the power supply, but still the same problem. I also made sure the cables were lined up properly so they ARE hooked in properly. Any ideas?
 
When you say the cable(s), are you talking about the ribbon cable too? Usually the ribbon cable being backwards causes that issue. Of course, it's quite possible that it's simply bad. You can go into the service menu and do the sound checks to see if anything plays.
 
When you say the cable(s), are you talking about the ribbon cable too? Usually the ribbon cable being backwards causes that issue. Of course, it's quite possible that it's simply bad. You can go into the service menu and do the sound checks to see if anything plays.
I made sure the ribbon cable was on there properly, but I WILL take pictures of the ribbon cable attached on each end just to make 100% sure I am not an idiot, but for all I know I probably do have them on there backwards. The sound checks do not play any sounds. The board actually shuts off after the rom check.
 
I made sure the ribbon cable was on there properly, but I WILL take pictures of the ribbon cable attached on each end just to make 100% sure I am not an idiot, but for all I know I probably do have them on there backwards. The sound checks do not play any sounds. The board actually shuts off after the rom check.

Hmm. That's a strange one. If you don't even get the initial "Bong" upon power application, then I'd say you have a voltage issue. Here's the pinout of the power connector...

untitled-4.jpg


...see if everything is correct. If it is and the ribbon cable is correct, you may have a bad sound board. Unfortunately, they DO go bad. I have a closet full of them. I have run into, on occasion, that a bad ribbon cable will cause the sound board to be intermittent. My old MK2 cab would have sound one minute, then nothing. I'd reset the cab and nothing. I'd change out the sound board and the sound came back. After cycling power, the sound went away again. Turns out the ribbon cable was bad. I replaced it and never had an issue again.
 
I would say also look for bent pins that may be bridging on the expansion board around the roms, etc. also. Look for scratched traces. It seems easy to cut a trace on the expansion board with just a fairly light scratch. I had to repair several traces on one of mine.
 
i would reseat and clean everything (chip legs, jamma edge), check your voltage at the board as well. bent pins are fine, pins touching other pins/traces/components is no bueno.
 
I figured I'd go ahead and give an update. I reseated the PLCC chips and sure enough the thing fired up without errors. Thank you so much! Unfortunately the sound problem is still persisting. I am pretty sure it's the cable though, since the power seems to go to it just fine until we plug in the cable. Any idea where I can find one of these (do I have to go online to find a matching cable, or will Fry's have what I need?)
 
It's a fairly proprietary cable (not much to it but it's game specific and all), Bob Roberts sells them for a really good price.
 
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