Mortal Kombat 1 Not Powering On

JasonSmith

New member
Joined
Dec 16, 2010
Messages
3
Reaction score
0
Location
California
I recently purchased an original Mortal Kombat Cabinet. I was told by the seller that it worked "as far as they knew", but the power cable was cut. I spliced on a new end to the power cable, plugged it in, and tried it out. Nothing seemed to happen. When I toggled the machine off, the monitor did indeed turn off. It made the normal shrinking rectangular shape you normally expect when powering off a CRT.

I opened the cabinet up and found some loose wires. There were 3 loose connectors, and a couple ground looking wires just hanging out. Of the connectors, a couple of them obviously went together. The connectors were proper male/female, had the same number of pins, wire colors matched, etc. There is another connector, however, that I'm clueless about what it is supposed to lead to. I attached some pictures of it below. There are 4 total wires that run to it. I have a manual I found online. Two of the wires go into the main PCB on(according to the manual I have) the J4 connector. The manual also claims those wires are control panel related, but those all seem to be wired up and heading elsewhere. I have verified one of the other wires goes to +12v directly on the power supply. The last wire is all black and I assume that it's a negative or ground wiring, but I have no idea. I can't find what that connector is supposed to connect to on the other end. Something coin op related?

Also, I was wondering where would be the best place to attach the ground cable that I have to attach. It is also in a picture below.

I was just reminded as well, I noticed this last night, but I don't have any pictures of it. While I was looking at the coin wiring I noticed a silver wire attached to the bottom of the cabinet in sort of a silver cloth kind of conduit or something. On the end it looks like another ground cable towards the front of the cabinet. It's also hanging loose.

From searching on here there seems to be a few that are pretty MK savvy, so any help is appreciated. I'd also love some hi res shots of other people's wiring in MK cabs if at all possible. That would help me out immensely, but I'll take anything!

Thanks again!
 

Attachments

  • IMG00079-20101212-1140.jpg
    IMG00079-20101212-1140.jpg
    86.9 KB · Views: 22
  • IMG00078-20101212-1138.jpg
    IMG00078-20101212-1138.jpg
    88.7 KB · Views: 22
  • IMG00096-20101215-1244.jpg
    IMG00096-20101215-1244.jpg
    88 KB · Views: 23
  • IMG00091-20101215-1238.jpg
    IMG00091-20101215-1238.jpg
    93.8 KB · Views: 26
  • IMG00086-20101212-1144.jpg
    IMG00086-20101212-1144.jpg
    98.1 KB · Views: 20
The green wire with yellow stripe is a ground wire. It should be attached to any exposed metal on the monitor frame.

The ground braid you are looking at on the bottom of the cab is a field ground. It should be attached to the monitor, control panel, coin door, and any other metal that may be exposed to the user (outside the cabinet). This will need to be connected to the ground wire on your power cable.

Do you have a multimeter? You need to check the power supply and verify that you are getting +5vdc. It sounds to me like your power supply isn't coming up and that is why your game is unplayable.
 
I was also suspecting the power supply myself to be an issue. The power goes into the isolation transformer before it goes into the power supply, so that would explain why the monitor gets power but nothing else does.

I do have a multimeter. I will play with that tonight.

If the power supply is indeed bad, is there a good source for ordering new ones? Or would it be easy/better to replace it with a normal PC power supply?

Thanks
 
Congrats on purchasing the MK. There are a lot of knowledgeable folks here and yes some that are pretty familiar with MK machines. I'm actually in the process of finishing up my MK semi-restoration and have had to deal with wiring issues. I'm not sure what that connector goes to offhand, but you've definitely come to the right place for help. I would definitely agree with Oryk Zinyo that it's a power supply failure. Looking at your 3rd picture, I'm willing to bet that's even the original power supply that shipped with the game so it wouldn't be at all surprising that it would need to be replaced. It should be a very simple process of just switching the wires over one at a time from the screw terminals on the supply. You may have to mount the power supply a bit differently if those brackets that currently hold it in place don't have holes that line up with the new one. In fact that's really the main reason I think yours may be original because it still has the brackets. You could of course drill new holes in the brackets if you wanted to keep them.
 
lately whenever I have a "dead" power supply, the first thing I try is "wiping" the +5 adjustment pot. often times these can become oxidized and can cause the power supply to go into overcurrent protection. you of course do this while the machine is unplugged, but don't just go powering it back on, because you won't have any idea what your +5 voltage is set at, and it can damage your game if it's set too high.

I actually took the lamp fixture out of one of those large lit buttons from a redemption game (alternatively, a coin door light fixture can also be used, but the terminals are very small on those and you might have to substitute some 22 gauge wire instead of the quick disconnect approach), crimped some wires onto the terminals and put .156 male molex pins on the ends for the use of placing a load on a switching power supply while there's no game connected to it. you may or may not know you can damage a switching power supply if there's no load placed on it.

now of course the molex pins won't plug into a screw terminal power supply, but that's where I use 2 sets of alligator clips: one set attaches each of the wires on my lamp to the +5 and COM (ground) on the screw terminals, and then I throw another set of alligator clips onto another portion of the molex pins that then go to my meter. for this test, you want your meter to be set on 20V range DC.

be certain your JAMMA harness is unplugged from the game board and anything else that could potentially be damaged by high/low voltage. alternatively you could mark off your wires attached at the power supply itself and just unscrew them out.

plug the game back in and power it on. adjust your voltage accordingly, permitting the power supply came back to life after cleaning the +5 pot. test the range of your power supply now, dial the pot all the way down, if you can reach about 4.85V with it, you're doing good -- means your lowest voltage won't nuke your hardware. :) then dial it up, can you reach about 5.5V without the power supply blowing up? if your range tops out at a very low value and you have the thing cranked, it's probably a good idea to replace the power supply. if you have a healthy high voltage, then your existing power supply should still be suffice.

dial the power supply to 5.10V. power down. reattach any wiring you removed (you use the +5, COM, +12, and -5 for MK) plug your JAMMA harness back in, then power up. does the game work again? :)

I know it looks like a lot to do, but this entire procedure takes me no longer than 2 minutes.
 
I had some time to sit down with it tonight and I must say I'm certain that power supply is dead. There is an LED on it that I had missed before. It doesn't turn on at all. It also has the original Midway "warranty void if removed" stickers on it like everything else in the cabinet.

What I'm intending to do is get MK running and also run MAME on the cabinet. At this point I'm thinking it might be wiser to just get a PC power supply. All I would need to do is dissect a molex connector and apply the +5, +12, and grounds appropriately wouldn't I? Then the marquee and everything would power on with the PC, correct? I can then wire the PC power button to another toggle on the cabinet somewhere. I'd have two power switches for the monitor and the PC, but that's ok with me.

If there is a hole in my logic will someone please shoot through it? :)
 
You should wire in the -5vdc as well. there is no real need to wire in a second switch. Supply power to the pc power supply from the same source as the currently installed switcher and jumper the power supply to always be on.
 
Back
Top Bottom