Do MK & MKII run on the same sound board?

keithsarcade

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The reason I ask is I have an opportunity to buy an MK upright with both boardsets, sight unseen but for a fair price, and the seller seems pretty honest, photos show a decent game....

Anyway he only has the sound board for MK and says the sound board dosent work with the MKII, but the MKII will play without sound. MK is working all the way.

So obvious questions are... are the sound PCB's any different between the 2 games? How common (and how expensive) is a sound PCB for MKII, is it possible that the main board is bad and not feeding a signal to the sound board....

Also curious where I can find a 2-1 JAMMA switcher. Anyone know? All I see are 6-1, dont want that one.
 
sound boards are different. MK1 runs a Yamaha-based setup, and MK2 runs the DCS sound system.

MK1 runs the same sound board as NBA Jam though. MK2's was unique, unless MAYBE Revolution X used the same kind, I've never even seen that actual game live though lol.
 
sound boards are different. MK1 runs a Yamaha-based setup, and MK2 runs the DCS sound system.

MK1 runs the same sound board as NBA Jam though. MK2's was unique, unless MAYBE Revolution X used the same kind, I've never even seen that actual game live though lol.

The majority of MK1 boards are likely to be "Y-Unit" hardware. Later versions of MK 1 (specifically version 5.0) ran on a board called "T-Unit" which also runs on NBA Jam I'm pretty sure MK2 as well. Now with MK2 there is a version of the board that has a "memory expansion" board mounted on top of the main board and a later version that runs without it. The PCB in my MK2 has that memory expansion board and luckily I've only had one time where I had to re-seat it to get the board working again.
 
The majority of MK1 boards are likely to be "Y-Unit" hardware. Later versions of MK 1 (specifically version 5.0) ran on a board called "T-Unit" which also runs on NBA Jam I'm pretty sure MK2 as well. Now with MK2 there is a version of the board that has a "memory expansion" board mounted on top of the main board and a later version that runs without it. The PCB in my MK2 has that memory expansion board and luckily I've only had one time where I had to re-seat it to get the board working again.

even the T-unit MK1 ran the old sound board though, it's the same one that NBA Jam has (another T-unit game as you mentioned) that required a 50k ohm volume pot. MK2 was the first game to utilize the DCS sound system, which if I'm not mistaken was engineered to have more better quality sounds using less data, it was a compression system. the only differences between Y-unit and T-unit MK1 are the revisions (Y-unit stops at 4.0, T-unit ran 4.0 and went up to 5.0) and the kick harness from MK2 worked on the T-unit board.

I've had relatively bad luck with my MK2 board, I too have had to reseat almost everything on it. when I first got it, it would reset and flash Custom Chip errors. reseating a few things fixed that. then one night I had looping babies crying sounds with the Wasteland music... that too was fixed with reseating. other than that the game works though.

this was a normal condition back in '94 when the hardware was new... my grandparents' MK2 machine did all the same things.

MK2 also came in a couple flavors, the one with the memory expansion uses 4 mb roms. later in the production run Midway fitted it with 8 mb roms, thus negating the need for the memory expansion. I'm sure those are way more reliable, but rarity is an issue with those. I've never seen one up for sale, for instance.

I'm no expert on these things, I've just been around them for awhile, if you had a game room in the early 90s and you didn't have any of the MK or NBA Jam games, you were missing out.
 
well, I'll go down the line.. :)

1) where to buy? you can find them on ebay usually.

2) is it a connection problem with the main board? possibly, there's 2 cabling setups that interconnect the main and sound boards: a power harness (6 wires) and a signal cable (what tells the sound board to play sounds, and what feeds the sounds to the main board to output from your speakers!) that's a 20 pin ribbon cable. commonly, people are lacking either one or the other. I say the easiest to replace with at-home components would be the ribbon cable, you can get away with using a computer IDE cable in its place, only making sure that you have both ends lined up. pin 1 for the sake of simplicity is the one you want to line the red stripe on the cable with on both sides. the power harness? well... you could always make one. I think it's 18 gauge wire, the service manual can give you the pinout information if you know how to make the slide on connectors. don't ask me what size, I don't know anything about that stuff.

3) sound board pricing: you could take the gamble with ebay and possibly overpay like I did or you can wait around for a KLOVer to sell MK2 (the complete set) and you can just hang on to the old board for a spare or use that and keep the new one for a spare. I've seen the game go for about $55 on here, just depends on which el cheapo undervalues it and sells it at. :)

4) will it work in an MK cab?: yes. as far as your sound goes though, I'd check to make sure the volume pot wasn't placed inline with the actual speaker wiring. it should have a 3 pin connector on the MK1 sound board that it plugs into.

5) JAMMA 2-in-1 switcher: if I'm not mistaken, these are very hard to find, I vaguely recall that they may have stopped making them, or I might be getting it confused with that Clay Cowgill switcher. be mindful that if you do somehow run across one, you will have to manually run jumper wires from where the -5V finger on the JAMMA edge is to each of the two game slots, because for whatever reason these 2-in-1 and 6-in-1 switchers don't run the -5V from the JAMMA edge directly to the slots, they're like dead-end circuits.

I think I covered everything.. anything else though, feel free to ask. good luck. :)
 
I see the MK 1 and 2 sound boards pop up on ebay all the time, you should have no problem finding one...

Good luck! Awesome game!! :)
 
yeah, seller GameboardsOC has always been good to me (has like a bbu34850632 whatever username) .. just make sure items are in "tested, working" state and you'll be fine.

I can't really see a sound board being in a condition that's unrepairable though, it's a friggin transistor and some caps right? (and roms, I guess)
 
Well I bought it. Got it home and much to my suprise, the MKII is a complete kit, sound board, cables and all. Of course the MK is working all the way (also complete).

So trying to get sound out of the MKII kit now. I see the wiring is a little different, that MK runs on a volume pot and MKII dosent. So far Ive tried tapping the speakers directly into the sound harness and also tried tapping into the +5v line and putting it into pin 4 at the P4 connector on the main PCB (needed?). Still no sound. Am I doing something wrong, or is there something wrong with my boardset?
 
test mode. go under Diagnostics, then Sound Test.

since you have NO sound, you will hear no beeps. however, if it says SOUND IRQ DETECTED, then it's something to do with your speaker wiring.

if it says SOUND IRQ NOT DETECT, then it's to do with your main/sound board wiring.

make sure that your ribbon cable's got the red stripe facing the 1/2 pins on both boards. it's easy to get one of the ends backwards.

lack of +12 and/or -5 will result in sound issues as well. however, if you have no -5, it will sound (quite accurately) like what the 7th level of hell would sound like.

you're just hooking the JAMMA mono sound wiring to the speakers right? both games are mono, they don't use anything fancy to hook up to the speakers. depending on how your cab is rigged, you MIGHT have to do what I did (I converted a stereo War Gods cab for MK use) and jumper the wires from one speaker to the other to get double mono. :)

check the service manuals for both games to get the pinouts on the power connectors on the sound boards (they're different, as we've established) to see what voltages are going to which pins. I wanna say it's as simple as red = +5, yellow = +12, probably the light blue = -5. I haven't fucked with these in a loooooooooooong time though, so my mind is hazy on the topic. (I ran UMK3 mostly since I bought it last Feb)
 
Heres what it says...

All cables check out. Only thing I'm noticing is the +5v on the sound PCB is getting 4.63v, too low? Basically I spliced into my speaker wiring right above the PCB (going to the speakers, not the pot) and tapped those into pins 1-2 on the 9-pin connector (for speaker + and -).

I can see in the manual that pin 4 of J4 is marked +5. I tapped into the +5 at the sound PCB for that, no difference whether I hook it up or not. Anyone know what that pin is for?
 

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use the JAMMA speaker +/- wiring on your speakers. I had no idea, sans the unamplified solder pads on the sound boards that bypasses the amplifier, that you could even connect the speakers to the sound board.

also, MK2 has a volume adjustment in the test mode. sure your volume's not way low in there? you should still hear the power on "BONG!" sound anyway.
 
Volume adjustment does nothing. So your saying instead of linking the speaker wires to the sound board, I should link the speaker + and - from the JAMMA connector to the sound board? Guess Ill try that tomorrow.
 
that's correct. :)

either MK board will be interchangeable. the volume pot just taps into a connector on the sound board and will be your volume adjustment. MK2's volume is set via the test mode.

the way you did it like I said might be unamplified, you could probably rig it that way if you were going to use it with a supergun or something since the sound boards are amplified and it would blow the speakers on your TV otherwise.

could very well explain why you had no sound, since it wasn't powering the speakers. your interconnect wiring between the boards is correct, as evident by your screenshots.
 
I chased the wires today, found out what you meant on the pot, it goes directly to the MK PCB. But I also chased the speaker wires and they go straight to the JAMMA harness, so in a way I've already tried that.

Any more ideas? I'd really like to know what the +5v pin at J4 is for, whether its related or not.
 
you talking about the +5 on J3? (J4 is the MK1 Player 3 harness)

the J3 one apparently is for the coin meter.

FYI:

MK1 manual: http://arcarc.xmission.com/PDF_Arca.../Mortal_Kombat_1_(16-40025-101_July_1992).pdf

MK2 manual: http://arcarc.xmission.com/PDF_Arca...rtal_Kombat_2_Kit_(16-44029-101 Oct 1993).pdf

you must have a broken wire or your speakers might be no good. find out the resistance (I think they're 8 ohm) and do a resistance check across the + and - terminals on the speakers with your meter and see if it's coming back 8 ohms. if not, then they're no good.

and obviously check the JAMMA speaker wiring, continuity, just unplug em and drag them back down, lol.

it's a fairly depressing story. I can't stand games with no sound.
 
Acually I meant P4, there are 4 pins and a key, and one of them is +5v (page 38 in the manual). I can either leave this pin alone or use the 5v from the sound PCB (basically what I'm saying is I have tried both), no difference. I also tried jumping the speaker wires for the interconnect cable, no difference.

I can rule out bad speakers or bad speaker wires since MK is working all the way.

I'm leaning towards a bad boardset or bad sound board at this point.
 
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