SNK U4 - Screen crackles and dies REDUX!!!!

For monitor related issues
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Buddyc
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by Buddyc »

It looks like you got a Nanao MS8-26 chassis in there.
You can download a English manual from this link
https://www.neo-arcadia.com/forum/viewt ... 14&t=61741

Looks like number 17 will help you out.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by thegreathopper »

Yes that’s my experience too, even when I had a cab with a factory fitted step down from Sega the screen wobbled, removed and all fixed.
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nem
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by nem »

Don't touch the jumper when the cab is turned on.

Also, can you take a picture of the sticker on the back of the tube? It will have the name of the manufacturer and the tube number.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by sven666 »

Yeah try the wide/narrow jumper (honestly never heard of it before), i had the screen dialed in perfectly before shipping..

The tube is a nanao also, dont know the numbers tho.

Ed: i guess its not, i have way to much **** and im always working on everything all at once, ill blame that..
Last edited by sven666 on April 9th, 2021, 9:42 pm, edited 1 time in total.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Hopefully the attachment works? I’m doing this from my phone and can never sort out image hosting like this :oops:

Thanks so much for the manual!!
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by Buddyc »

You are most welcome!
Great looking cab! Can’t wait to see it calibrated to perfection.

And like Nem said. Don’t touch jumper 17 while cab is on.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

thegreathopper wrote: April 9th, 2021, 8:54 pm Yes that’s my experience too, even when I had a cab with a factory fitted step down from Sega the screen wobbled, removed and all fixed.
Not something I’m massively worried about right now, but would you suggest putting a new PSU in might sort it?
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

sven666 wrote: April 9th, 2021, 9:25 pm
The tube is a nanao also, dont know the numbers tho.

Ed: i guess its not, i have way to much **** and im always working on everything all at once, ill blame that..
Ah, so is that why plugging the degaussing button back in sorted the discolouration??
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by SuperPang »

ChrisBEANS wrote: April 9th, 2021, 10:27 pm
Not something I’m massively worried about right now, but would you suggest putting a new PSU in might sort it?
You’d want to take it out, wire a Japanese power cable and use an external step down (Airlink JA0250).
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by thegreathopper »

Yes as Joe has suggested, that’s the route I would take.

Great looking cab, I was very close to hitting buy
when it came up but knew you were hunting one down.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by grantspain »

just a bit of info for you, wobble tends to be caused by three things- b+ chassis regulation or chassis mains smoothing, degauss issues or electromagnetic fields
if your screen is affected in one area only then it rules out the former of the two and points strongly to an electromagnetic field- as pointed out by others most likely to be the internal stepdown too close to the deflection coil

the width coil will only give a few cms adjustment and as previously stated the width jumper is more likely to resolve your issue
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Brilliant, cheers all.

Hopper, I promise I’ll try and do it justice!!

I’ve actually made a massive error in that I lack the space (and clearly the knowledge) to look after a cab... and I’ve bought three!!

Still got two to come.

The really good thing about that, is there’s another four slot coming (and a six slot board) and I’ve got an external transformer coming too.

Think I’m going to need a lot more advice along the way :wtf: :-P


Not sure if I’m going to be able to get to the jumper this weekend, but if that sorts it, I think we’re pretty much there on the screen!!

Thanks again all. Genuinely grateful.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Buddy C... I could kiss you!!!

Image

That photo was taken by holding my phone in a small gap between the chasis and the back of the screen, and that wire seems to be phyically impossible to actually get to, but the fact it's there, and it's set to wide, is fantastic news!!

I'll report back once I've moved it, and assuming I haven't broken anything while trying to access it :lol:
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

So...

Image

Image

Still too wide (you can see the avatar picture thing in the top left of the game screen), but much better than it was, and hopefully the last bit can be sorted with the trimming tools that are on the way.

Same issues with sound on everything but MS5, but I'm still waiting on the JAMMA voltmeter to arrive to see what it says. I've got a JAMMA board, and and AtomisWave (and the JNX JAMMA to MVS adapter) but I've been advised not to plug anything else in until the volt meter arrives and I can see what it says.

I do have a multimeter... Can I use that without breaking stuff?
Last edited by ChrisBEANS on April 12th, 2021, 9:20 pm, edited 1 time in total.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by cools »

Image
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by Buddyc »

I do have a multimeter... Can I use that without breaking stuff?
[/quote]

You can use the multimeter to measure 5v, 12v and on the MVS harness.
Heres the pinout from your cabs manual. Black probe on Gnd and red on 5v with multimeter set on DC voltage.
017F5B5D-2CAA-4569-86E7-F11DCB0633DE.jpeg
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Ok, so I'm 90% sure I've done this right...

Going by the diagram above, pins C, D, 3 and 4 all show 5.24v. Pin F shows 12.1v and pin 6 shows 0v

Edit: hilariously, I’ve no idea which way up the JAMMA/MVS edge was when I removed it, and now I’m too scared to put it back on :lol:

2nd edit: found a photo from before I removed it. Writing side up. Phew!!
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Apologies for the deluge of stupid questions, I'm just trying to make sure I treat this thing with the utmost respect rather than taking my best guess and ruining it!!

I assume this dial will adjust the voltage slightly? Slight turn anti clockwise to try to get it down as close to 5v as possible?

Image

Edit: It was, I got brave and had a play. It's now at a perfect 5.0v on all four pins.

Same sound issues sadly...
Last edited by ChrisBEANS on April 12th, 2021, 9:37 pm, edited 1 time in total.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by geotrig »

:thumbupright: yeah 5.24 is way too high

When changing between boards it always worth rechecking also as draw from boards can affect it
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<trk>:I remember catching a big fat one and my friend said "throw it back in, that one already tastes like wood"
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by geotrig »

Is your jamma edge "keyed" ?
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<trk>:I remember catching a big fat one and my friend said "throw it back in, that one already tastes like wood"
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