X-Men Buzzing - Connector Issue or Board Issue?

64B1T

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Here's a video of the issue in question. Our X-Men 6P has developed a rather nasty intermittent Buzz. I'm trying to determine if this is a connector issue or a board issue. The audio module on this machine has been replaced, so I don't think it's that.

Messing with the connector/pressing the connector/board as shown in the video has also resulted in the system resetting... Or the buzz disappearing. What could this be? What's the best way forward?
 
Okay so I plugged my Konami Aliens PCB into the cabinet and it came up fine, and then I realized something:

X-Men (6P) doesn't route speaker connections through the JAMMA connector anyway. They're on a 4 pin connector on the main board. So that test was never going to reveal if there was a buzzing problem or not.

I ended up taking a look at the connector and noticed that the power pins seemed a little flat. I took a pair of tweezers and bent them back toward the center a bit. Plugged it back in and it came up with great audio. It's running right now, so far so good....
 
Went ahead and played another long game on this thing today. Midway through the game, the buzz came back. Damn.

I fiddled with the edge connector and the buzz stopped and the game reset. Double damn.

One thing I noticed though - or thought I noticed - when the buzz happened, I noticed a distortion on both monitors. Very minor, but I thought I saw it.
Hmmm.

Could this be a PSU issue? The power supply in the 6P X-Men cab is a Peter Chou USP-11-150X. I note that there's a cap kit for this thing on APAR.
Is this PSU worth rebuilding? Does it need rebuilding? How would I tell? I did have a situation a couple weeks ago where the breaker tripped when I powered the machine on. I didn't think anything of it at the time....

The next thing is if I go ahead and try to rebuild the jamma connector, are these the proper pins for most harnesses?
 
Clean and DeOxit all connections.

This means everything. Any place where a wire is connected to something else (through a pin, terminal post, etc). I'm not familiar with that PS and what connections it has. But if wiggling wires changes things, you could very easily have a spot of oxide at some contact point, that you can't easily see.

You want to hit all contact points with something abrasive (fiberglass pen, Dremel wire wheel, 2000-grit sandpaper) to remove anything you can't see. Then DeOxit and reseat.

Sorry if it sounds simplistic, and is the same thing I say in many threads here. But oxidized contacts are responsible for a HUGE number of problems in this hobby. Especially when you're seeing flaky behavior.

People go hog wild replacing and repinning connectors, and it's often overkill and unnecessary, when all that's needed is removing a tiny bit of junk at the contact point that is interfering with two pieces of metal touching.

Also be aware that crimps can go bad as well. Any time two dissimilar metals touch, you can get oxidation between them. That includes between tin connector contacts and copper wires. But if there's a bad crimp, you should be able to narrow things down and find it, and just fix that one connection (often without even needing to replace the pin), and without needing to repin whole connectors.

Visual inspection under a BRIGHT light also often goes a long way here.
 
Clean and DeOxit all connections.

This means everything. Any place where a wire is connected to something else (through a pin, terminal post, etc). I'm not familiar with that PS and what connections it has. But if wiggling wires changes things, you could very easily have a spot of oxide at some contact point, that you can't easily see.
The only thing I'm wiggling to affect anything is the edge connector. I've already gone through and deoxited it and the fingers on the jamma board, with a fiberglass brush attached to a power drill.
Also be aware that crimps can go bad as well. Any time two dissimilar metals touch, you can get oxidation between them. That includes between tin connector contacts and copper wires. But if there's a bad crimp, you should be able to narrow things down and find it, and just fix that one connection (often without even needing to replace the pin), and without needing to repin whole connectors.

Visual inspection under a BRIGHT light also often goes a long way here.
I did inspect everything under a bright light, and other than a few recessed pins which I noted above, everything seemed to be in order. I think whatever is going on here is on a different level.
 
If wiggling things changes things (and makes something go away completely), something isn't making consistent contact.

However if you're going to wiggle and touch things, try using a plastic or wood tool (like a dowel or handle of a wooden spoon) instead of your hand.

I watched your video, and you're sticking your fingers in there. I can't see what you're pushing on, but your fingers have electrical properties, enough to affect signals sometimes (especially for AC and audio circuits). So you want to tell the difference between something actually being a loose connection, and not your fingers grounding something out, and making a problem appear to subside.

Also, pushing on boards can flex them in ways that can cause things like cracked joints to make contact in areas away from the area you're pressing on. Pushing gently with a stick can better isolate the thing you're trying to touch, without flexing the whole board.

Also, is there anything special about that PS? I'm not familiar with it, but do you have the option of just swapping another PS in there, just to test?
 
Still sounds like dirty/loose audio ground whether the 4p or JAMMA. The 4P is just 2 channel coming off amp. One of which is same as JAMMA if you look closely at circuit. Doesn't take super cleaning with a drill to handle this. If flexing JAMMA kills pcb, I would assume super dirty connections or bad connections solder side of connector. Hopefully you are not flexing enough to crack pcb. If that's the case you will be looking for a replacement pcb.
 
Back to the basics... Measured voltages on the board.

12v line is a perfect 12.00V. Very nice.
5v line... Coming in at a measly 4.59v. It's a miracle this thing is running at all. I'm guessing that PSU needs a rebuild.

The coin door bulbs are even lower, at 4.4v. No wonder they're dim.
 
Game Bd will stall out at around 4.70v. Not sure how you are measuring but I cant see Game Bd running at 4.59v. Make sure you are measuring correctly before adjusting voltage.
 
Game Bd will stall out at around 4.70v. Not sure how you are measuring but I cant see Game Bd running at 4.59v. Make sure you are measuring correctly before adjusting voltage.
Screenshot_20250406-160853_Gallery.jpg

There a better spot than these pads to measure from?

I also clipped leads on to the lights in the coin doors.
 
No that is perfect, Just use that 5v and ground return next to it. Looks like this is one of my hybrid installs. Why don't you call me when you are in front of game. Might make this faster.
 
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