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Mortal Kombat II board help

aha2940

aha2940

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Hey guys

I have a complete MKII board. It's the big model, with the expansion board and 4Mb EPROMs. It also has the sound board and connecting cables. Anyway, ever since I got this, it has been difficult to turn on. Sometimes after removing/reseating the battery, reseating the EPROMs it would work, but now it does not do anything. I connect it, one of the LEDs on the big board (it has 2 LEDs) will turn on, it will stay on forever. The other LED will not turn on at all. The board does the same with or without the sound board. I do not know if there's anything on the screen, because I use it with a gonbes8200 vga converter, which will not display picture unless the board feeds it complete nice image. I do not have an RGB monitor to test.

Any idea what can I do to fix this? any tests that I can do to get better information? What do LEDs on the big board mean?

Thanks for any help guys.
 
One LED is for Power, the other seems to be memory access because even on a health working board it flickers seemingly randomly with action on the screen.

I don't know if the G8200 will even scale MK2 properly, you might be sitting on the bootup test screen and not even know it (you could press player1/2 start to bypass if you are).

Pulling the board battery will have zero effect on booting, tho a board with a working battery will boot slightly faster because it won't wait to error on CMOS settings.
You can also change a jumper to disable CMOS settings and use DIPs, search KLOV because I forget which (I've since sold my board).
 
The gonbes from jammaboards.com definitely works with mortal kombat (in fact, they specify so) - I'm using it with my UMK3. So pick on of those up if need to use it with a monitor, I'm not sure if there's any other guaranteed way of doing so...
 
fluxcore said:
The gonbes from jammaboards.com definitely works with mortal kombat (in fact, they specify so) - I'm using it with my UMK3. So pick on of those up if need to use it with a monitor, I'm not sure if there's any other guaranteed way of doing so...
Click to expand...
I forgot to mention, I have managed to play this very same board before, using the gonbes8200 I already have. I had to tweak the gonbes settings a bit for it to show image, but for sure it has worked before with my setup.

Also, just to test, I dumped all of the boards' EPROMs, however I found no set to compare it to. I got the mk2.zip set for MAME, but only the sound roms match, the game ones are all 8Mb on the MAME set, mine are all 4Mb. In case anybody is interested, just PM me and I'll let you have the 4Mb roms.

Thanks!!
 
The MAME set is from the version of the board without the daughter ROM board (larger sized chips so less quantity used).
If you BINARY copy the ROMs together, the resulting CRCs should match MAME set.

I gave my G8200 to werejag so I wasn't sure if it would scale MKII, my official Taito JAMMA kit will not.
That's why I sold my working/complete mobo to Jdurg, I still miss the game but I just couldn't play it properly.
 
Hey!

Sorry to necrobump this, but I recently started playing again with this board to see if I can fix it. I am trying to (at least) diagnose which part is the broken one (sound board, main board of the small extension board). My question is: does anybody know what should this board do when connected with no ROMS at all? does it throw something on screen? mine throws nothing at all, with or without roms...

Thanks!!

Edit: So it seems I am kind of an idiot, because I did not follow correctly the first rule of reparing arcade boards: check the solderings. I checked them again, and for sure, 6 or 7 were broken on some through-hole chip. After reflowing them, the board seems to be fixed. Now gotta fix the MK3 board I have throwing random messages about U49 chip (which sadly is not through-hole, therefore no idea how to reflow it)....Definitely MK games hate me.

Thanks!!
 
Last edited:
UMK3 hates everyone, I have a working one and a non working one, the non working one sometimes boots and then resets during the tests but since I checked the ROMs and reinstalled then it now won't boot at all.

From what I understand though the previous owner wired it up badly and fried the +5v on this and the NBA JAM I bought from him, I was hoping to get them going again but I think they're too far gone, still possibly good for potential parts for my working board though.

If you think Mortal Kombat boards are bad, Killer Instinct is worse :( I have a working one and I'm terrified of it dying, they're almost impossible to fix and these days are very very hard to find
 
xodaraP said:
UMK3 hates everyone, I have a working one and a non working one, the non working one sometimes boots and then resets during the tests but since I checked the ROMs and reinstalled then it now won't boot at all.
Click to expand...
By just dumping and reinstalling them? Are you sure everything is fitted and soldered correctly?
 
aha2940 said:
Edit: So it seems I am kind of an idiot, because I did not follow correctly the first rule of reparing arcade boards: check the solderings. I checked them again, and for sure, 6 or 7 were broken on some through-hole chip. After reflowing them, the board seems to be fixed.
Click to expand...
It seems I jumped to conclusions too early. While the MK2 board is definitely improving, (it has not failed to power-on once since the soldering reflow) it's still not 100% right. It will reset randomly, and sometimes it will throw errors during the initial test. The error are not consistent, they will be on different chips each time (some times the scratch RAM, some times some ROMS, etc.). Sigh. These boards are a PITA, gotta check it again and see if I can find what's the issue.
 
Asayuki said:
xodaraP said:
UMK3 hates everyone, I have a working one and a non working one, the non working one sometimes boots and then resets during the tests but since I checked the ROMs and reinstalled then it now won't boot at all.
Click to expand...
By just dumping and reinstalling them? Are you sure everything is fitted and soldered correctly?
Click to expand...
Yes to the through hole components, but the vast majority of the board is SMD with a stupidly fine pitch or PLCC components so I can't be 100% sure
 
My UMK3 was faulty until I pulled the PLCC (U43 iirc) and cleaned its pins. Maybe give that a shot...
 
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