Sudden MVS 4 slot issue and don't know where to begin.

badcarwash

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Nov 30, 2019
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I bought a dedicated Neo-Geo MVS 4-slot cabinet last November. When I bought it, the machine worked. At that time, I hadn't kept it on for more than an hour. I would play it for 30-45 minutes and turn it off without any issues. All that was needed was cosmetic fixes to the outside of the cab. I did notice a high-pitched noise coming from somewhere and I thought it was the ELA panels which did not work. I couldn't work on it over the winter, so I kept the cabinet in my garage during the season. I took the board out and kept the board inside my house.

I read that these things are notorious for the leaking battery. So, I replaced the battery with a new one from twistedquarter. There was no sign of any acid damage from the old battery. After replacing the battery, I put the board back into the machine. It booted up normally with no issues. I still heard that high-pitched noise as before. It sounded like it was coming from the monitor area, but I couldn't really tell.

I wanted to keep the machine on to make sure that the battery would recharge to keep the scores, date & time, and everything else. So, I decided to keep it plugged in and come out to check on it after an hour or so.

I went out to it after an hour, and the machine appeared dead. I did not see what happened to it. I turned it off and on again. The monitor still has neck glow, and I can still hear static coming from the monitor when it turns on. But, there's no sound, and no sign of life from the game. It isn't playing blind-- It's just not playing anything! And this time, I noticed the high-pitched noise was also gone! Also interesting to note is that the coin counter LEDs on the control panel are also not turning on either.

This is my first arcade machine, but I've done some research on them. I am willing to do whatever repairs are needed. However, with this issue I do not know where to start. I've tried to do some Googling and forum searching. But, the "no video/no sound/power to the monitor" issues are so broad that I can't pinpoint where to even begin. Do I begin with the power supply? Fuses? Monitor issues? RAM? PCB Issue? All of these things come up when I try to look up the symptoms. I have no idea where to begin on finding the problem, or if this is a known issue for the MVS. Any guidance on this problem or even pointing me in the right starting place would be greatly appreciated!
 
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wyo

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The high-pitched whine is likely to be the PCB that controls the EL panels. You can disconnect it either at the motherboard or the PCB itself which is located behind the panels.

If the cab still has its original power supply, you should replace it with a new one from Suzo Happ and hope it didn't fry the motherboard or you will have to repair or replace that as well. I'd start with that and go from there.
 

badcarwash

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Nov 30, 2019
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If the cab still has its original power supply, you should replace it with a new one from Suzo Happ and hope it didn't fry the motherboard or you will have to repair or replace that as well. I'd start with that and go from there.

The original power supply was taken out and replaced with some kind of PC power supply. Don't know when that was, but it was before I had it. It isn't a Suzo Happ one. It kinda looks like a hack job, to be honest. But it worked when I got it last November. I'll look into the power supply and try to get a new one somewhere.

Also, I took the board out and inspected it. I don't see anything fried or burnt. But, I don't know if that kind of damage would be something visible?
I hope that's not what happened. But, noticing the EL panels no longer making a sound, the coin counter LEDs not turning on, and no sound has me worried. The only life that happens is that I hear the monitor turn on with static. Zero picture of any kind. :crying:
 

ack

Ninja Combat Warrior
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Apr 9, 2009
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537
It kinda sounds like the DC side of the powersupply could be dead. You should try measuring the 5V rail with a multi-meter to see what its shows.
 

ChuChu Flamingo

We have purposely, trained him wrong, ...as a joke
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Nov 23, 2010
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Sounds like your power supply isn't working if it is playing blind. Your monitor being black means your chassis is probably working fine. It just means your power supply (most likely since your lights are not working and sound) or game board are not working. Usually when a monitor dies you would still hear game sound.

I would verify the 5V rail is good on your power supply like ack stated. Check at the jamma edge where it connects to your mvs board, not where it comes from (since there is voltage drop if you check the terminals at the psu).

Tl;dr set your multimeter to 5v DC put ground probe on Pin 1 Ground of the jamma harness, Red probe on Pin 3 of 5v. It should be 5.0-5.05.

jamma_pinout.png
 
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badcarwash

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Nov 30, 2019
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Well, I went out and poked around some more. I found that I am in fact getting 5.06v and 12.03v exactly at the harness when the game is turned on, at all the points that I should be getting those voltages. Ugh. I don't know what that means for me?

I did buy a new Happ power supply, and it's coming in the mail. But.. I don't know if that is needed anymore?

Another thing I found out today.. after I took out the board completely. The first EL panel lights up. Why would the EL panel light up WITHOUT the board hooked up at all? Is that normal? I thought the EL panel was controlled through the board?

Other than that, I am not sure. I am still getting zero game sound. No credit counters light up. And the monitor does still get power, but absolutely no picture. It isn't playing blind. It's just dead other than the one EL panel and the monitor static.

I am hoping that my actual board isn't fried! Any ideas? :conf:
 

badcarwash

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Nov 30, 2019
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Another update:
I just plugged the harness into the board. Did not hook up EL panels, credit counters, headphones, or memory cards. The game turns on now!

Now I need to figure out which of those things are causing it to turn off...
 
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