mortal kombat 2 With no sound

INOVERMYHEAD

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mk2 has no sound, sometimes i think i can kinda hear something, but nothing, any ideas??? might i need to replace caps on sound board??? i do hear sketching/scratching threw speakers so i know they are getting some kinda signal. . .
 
you have a variety of areas to check here.

if you go into Test -> Diagnostics -> Sound Diagnostics, check that the sound board is passing the sound test. if your sound board isn't working properly it will display an error message along the lines of "SOUND IRQ NOT DETECTED".

if this is the case, then check to make sure your cables are attached properly to the sound board, making sure (as noted above) that the ribbon cable's red stripe side is aligned with the 1 pins on both the main board and sound board.

do the same with the power cables too. make sure you didn't hook those up backwards. the boards are labeled at the headers which pin is pin 1, just make sure the light blue wire is in the same locations (I wanna say this goes on pin 1) on the main and sound boards.

if all your cabling is installed properly and you're still having problems, then we move on to the next part...

my MK2 did this where it worked fine, and then suddenly started tweaking out. if you're getting garbage sounds or hearing babies crying (lol), then make sure that ALL of your sound roms on the sound board are seated in properly. I personally would suggest removing all the roms and if you have a can of compressed air, spray the rom sockets clean (making note, obviously, of the rom locations -- the original labels usually peel off -- your best bet in this case is to do 1 rom chip at a time) and then reinstall the rom back in the socket, ensuring that none of the pins were bent during removal, and that you're inserting them back into the holes on the socket properly. :)

for added measure, you should probably do the same on your main board as well, but I will admit the memory expansion board is kind of a complicated monster to work with. I don't know your skill level with this stuff.

as mod said, you should check your voltages if you know how to.

if not, let us know. if you need a manual for a pinout: http://arcarc.xmission.com/PDF_Arca...s/Mortal_Kombat_2_(16-40029-101_Oct_1993).pdf

good luck. PM me if you need help, my MK2 board was the only one of my MK boards that's ever federally fucked up on me.
 
My +12 is at +11.93 y -5 is like 4.89, I dont want to adjust the dial any more cause my +5 is at like +5.07.. . Those should be good ratings,Right???

Another part of my problem it its a conversion machine, not dedicated cab. . It looks really cool. its a deta east cab with the domed out marquee and the 19" monitor was swapped out for a 25" monitor, which has been a huge pain in the ass getting to work. but the cab was free so i cant complain too much. . . .

Keep comming with the ideas, they always help. . . .
 
I can also say from experience that you can accidentally scratch a trace on these. Especially if you have the version with the expension pcb. You could check for broken traces also.
 
5.07 isn't very high, particularly not for this game (you have to consider you're powering 3 boards: the main board, the expansion board, and the sound board).

your test point matters too, I can't remember exact numbers, but I had a drop in voltage from the JAMMA edge to the sound board. in the grand scheme of things, I wanna say I ran 5.15 on mine, you can go higher than 5.00, just not TOO high. once you start approaching 5.30, then it's risky, unless it's a game that consumes a lot of power.

for what it matters, Randy Fromm uses 5.10... I personally go a little higher than that, 5.15 at the JAMMA edge, that's a pretty solid voltage. I always tell the story about our Road Burners on this topic: this is a game that mind you is hard drive based, running 5 and 12 volts, and the +5 at the power supply was 4.86V. I only noticed the problem when one day it errored and reset with the "3 strikes" read error from the hard drive. Fromm's Blue Book cites a story about a WWF WrestleMania (a Midway Wolf unit, like MK3) that would reset when the voltage was at 5.00 or greater, but ran perfectly fine at 4.9V. each board has its own voltage tolerance, I guess is the moral of the story.

your ideal test point would be an IC on the board, but I honestly can't remember off the top of my head which legs you test from (mod, someone smart, help me here :)) and there's a high risk that you can "slip" off one of the legs and short them together, so I only advise this once you're pretty handy with this stuff.

in the case of MK2 though, I'd say the safe test point would be the sound board, not sure if that's in fact where you checked though. it's worth noting that on switching power supplies, only the +5V is "regulated" (meaning, that it will run only at the setting you made at the adjustment pot) and all the other voltage rails will be a little imperfect. my MK2 metered at around 13.2V on the +12V, it's nothing to worry about.

considering my Road Burners story, and how the game ran perfectly fine for over a year in a business setting, I'm inclined as to say the < 12V that you're getting is not the cause for the lack of sound.

I'd lean towards checking the roms (as I mentioned in my previous post) that they're all seated in, that your cabling is sound (run continuity checks on each wire from the main board and sound board headers that it plugs into), and inspect all the boards for broken traces. the Williams/Midway stuff is pretty easy to check this for, it's nothing overly sophisticated and advanced and fine-traced like the Japanese manufacturers.

also, fun little tip for your sound ribbon cable -- if you don't have another one to test with, you can use a regular computer IDE cable instead. just make sure you have the orientation of the cable right (red lines = pin 1). you can use a "keyed" IDE cable (with one of the middle holes blocked off), one side of that keyed hole will fit exactly on the ribbon cable connectors on these boards.

add that IDE cable check to your list of things to try. otherwise, there was a big name user on here that recently had their MK2 up for sale *wink wink*

good luck, sorry for the mouthful, but I enjoy passing on my useless experiences to others so they avoid the hassles I went through.
 
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