Mortal Kombat 1 Joystick issue/ Sound issue

Cloverdragger

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I have a T2 Judgement day, and Thinking about trade with someone local for a MK1 machine.

He does not have Side art on his cabinet, the sound has an error under the diagnostic that says "no IRQ detected) and the 1st player joystick is stuck moving forward/backward.

Easy fixes? I'm watching a sound board on FleaBay, but not sure about the joystick issue.

Help/?
 
joystick problem is easy, mostlikely the female spade connector is on the wrong post of the cherry switch (2 second fix).

The sound board could be a multitude of things, i suspect the ribbon cable is backwards or there's a problem with the other connectors to the board. (voltage/missing connectors)
 
joystick problem is easy, mostlikely the female spade connector is on the wrong post of the cherry switch (2 second fix).

The sound board could be a multitude of things, i suspect the ribbon cable is backwards or there's a problem with the other connectors to the board. (voltage/missing connectors)

Thanks for the input!! I'm trading arcades tomorrow afternoon, and making him chip in 50.00 for its issues.

I'll post pics tomorrow, All the help is MUCH APPRECIATED!!!
 
GOT the game home, and already figured out the joystick problem, wires were backward (THANKS STEVE!)


Will post pics of this tomorrow, along with what I have done to trouble shoot the sound problem.
 
ah you got his t2?

Nope. But when he was trading the T2 for the MK, he wasn't paying attention and broke every adjustment pot on his remote monitor board. So, he called me and I had him check to see if the MK had the same monitor. It did, so he swapped the remote board from the MK to the T2 to fix it for that guy, then brought the thing to me so I could fix the remote board for his MK....
 
ah it's starting to make sense now, i thought i was missing a post somewhere. i hear remote boards are hard to come by.
 
ah it's starting to make sense now, i thought i was missing a post somewhere. i hear remote boards are hard to come by.

You can buy new ones for some WG's from arcadecup. I have a box of extras that will eventually go back with a chassis...
 
OK, GOT PICS!! while its torn down, LOL


So i found that there IS power going from the CPU board TO the sound board, and all the grounds check out. I check the speaker and altho she looks rough, I tested with a 9V battery and it worked. My UE 13 never lights up on the ROM boot up screen. (U13 is on the sound board) I got rid of the "IRQ not detected" by I think plugging in the wiring harness (looked to be unplugged when I got it home and apart.

NOW, there are 3 big L1 chips on the sound board and 1 little chip that can be removed (sorry I don't know the proper lingo!! ) and the only chip that creates heat is the little one, the 3 larger chips stay cold. All caps look good.

Anymore advice?


IMAG0276.jpg




IMAG0278.jpg



IMAG0279.jpg



IMAG0277.jpg



IMAG0281.jpg
 
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i can't tell from the pics but is the red wire of the ribbon cable at pin 1 on the sound board? (it doesn't say pin 1, it actually says 2) basicly red side of wire should be at (2) instead of 16 or w/e on both boards.

other than that everything looks in order. what were the voltages on the soundboard when you tested?

i just looked at my nba jam te and it looks the same so it's not your ribbon cable (unless it's bad).

also check the resistance on that speaker (even tho it passed the 9v test it might be creating a high resistance?)

I don't own this game but i own nba jam, nba jam TE, and UMK3 so my help is limited, i don't know about the u13 sorry.
 
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i can't tell from the pics but is the red wire of the ribbon cable at pin 1 on the sound board? (it doesn't say pin 1, it actually says 2) basicly red side of wire should be at (2) instead of 16 or w/e on both boards.

other than that everything looks in order. what were the voltages on the soundboard when you tested?

i just looked at my nba jam te and it looks the same so it's not your ribbon cable (unless it's bad).

also check the resistance on that speaker (even tho it passed the 9v test it might be creating a high resistance?)

I don't own this game but i own nba jam, nba jam TE, and UMK3 so my help is limited, i don't know about the u13 sorry.


Thanks for the help tho! The voltage was 11.7 and 4.7. I figured that was close enough to 12v and 5v.

I will double check the ribbon cable tonight, maybe i should buy a new one?
 
yup there's a knob on there (the power switcher) to adust it i'd unplug the jamma connector from the game and power it up to test with volt meter, rather than adjust voltage with the game plugged in and on.
 
Welp, Played with the power switcher and got it up to 5.01 volts, the 12V went up to 12.18. Still no sound tho...
 
i booted up my nba jam today and noticed my u13 doesn't light up either, but my sound works. so that answers that question for you.

maybe check the resistance on the volume pot? that would rule out all the basics as long as you've tested voltage of the wires in the molex at the sound board including -5v

beyond that i'm stumped as i don't own mk1 yet.

also just for the heck of it, do you have another board you can throw in just to see if the speakers and wiring work. (you might have already tried this and i over looked it). also there's only 1 volume pot in the machine right? (sometimes there's one by the coin door (not sure about in mk machines tho).
 
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i booted up my nba jam today and noticed my u13 doesn't light up either, but my sound works. so that answers that question for you.

maybe check the resistance on the volume pot? that would rule out all the basics as long as you've tested voltage of the wires in the molex at the sound board including -5v

beyond that i'm stumped as i don't own mk1 yet.

also just for the heck of it, do you have another board you can throw in just to see if the speakers and wiring work. (you might have already tried this and i over looked it). also there's only 1 volume pot in the machine right? (sometimes there's one by the coin door (not sure about in mk machines tho).


Man, you've got all the trails down! I don't have another board, so I have not gone that route. There are actually 2 volume pots, one mounted to the plywood and one mounted in the coin door, I have tried adjusting both with no results. I was curious if one might have been messing with the other.

Have not checked resistance at the volume pots yet, I'm a nooby nooby noob, so still learning!
 
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