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

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

Post by ChrisBEANS »

So my much anticipated U4 arrived today.

Plugged it in, it came on, and so I went into the hardware test menu.

Into the I/O screen, and all the P1 buttons registered, but when I rotated the P1 stick, the screen crackled and then went off.

I switched it off and back on again, and the below video is exactly what happened.

Any ideas??

Last edited by ChrisBEANS on June 7th, 2021, 4:11 pm, edited 1 time in total.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by SuperPang »

Sorry to hear that. You must be gutted.

Someone who knows what they're talking about will be along in a minute but I don't think it has anything to do with the controls, I think the monitor has developed a fault in transit, in which case you'll need to send the chassis off to @grantspain for a service.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Pretty sad!!

If it is something as simple as getting something serviced, that'd be great. I completely understand these things are old and require maintenance, but I am pretty miffed I didn't even get to use it at all!!

P.S. thanks for the forum move and the edit :)
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by grantspain »

check all the connectors, neck card is fully home and remote board connectors and crt earth to neck card

you went into horizontal failure at the point of shutdown
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by SuperPang »

Just steer well clear of the anode cap.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

I'm afraid I might be well out of my depth here... First cab...

Assuming this is the neck board, it all seems secure

Image

Big lump of white guff on the back, but I'm assuming that's not the issue??

Image

As for it all being earthed... Everything that's plugged in seems to be plugged in firmly and apparently correctly. Only anomaly is this wire that seems to be coming from somewhere around the front of the monitor that's not plugged into anything. It was tucked behind some other wires though so it's not like it's come loose from anything, seems it was never plugged in to anything?

Image

Also, seems far too thin to be an earth anyway I'd guess...?
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by nem »

That will go to the neck board. There's going to be an empty header pin for it. Should be on the bottom, just out of view in the pic you have uploaded.

Out of interest, I don't think I've seen this neck board before. What does the A-B switch (SW331) do?
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by Ioncannon »

In fact I think I see it in the neckboard photo, far left of it.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by grantspain »

get that wire back on the neck card if its the crt earth i mentioned in my last message- its critical
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

There doesn't seem to be a place for it??

I'll have a good go at taking a photo of the other side of the neck board but it's a blood tricky angle!!

In other news, there is a random earth wire just loose in the bottom of the cab! Is there somewhere specific I should attach it??

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

Post by cools »

The neck board is safe to remove when powered off. Gently pull it towards you, you'll need to wiggle it slightly as you do so.

Take a photo of it then.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by nem »

The green earth wire should touch the metal shell. Place it under a screw if you can't see an obvious place for it.

It's also irrelevant for the monitor working or not.
Last edited by nem on April 6th, 2021, 3:59 pm, edited 1 time in total.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by geldra »

Got no advice to offer but WELCOME TO THE HOBBY! This type of bullshittery will be your life from now on. 8-)
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Image

Image

Image

Ok, so here are the best pics I can manage of the neck board...

Only place I can imagine the dangling wire may go is onto 'CN301', that you can see in the bottom picture??

Again though, it definitely hasn't come loose from there in transit as it was tucked behind some other wires...

In the mean time, I'll attach that earth to a screw somewhere.

Thanks again for the help...
Last edited by ChrisBEANS on April 6th, 2021, 4:08 pm, edited 1 time in total.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

cools wrote: April 6th, 2021, 3:55 pm The neck board is safe to remove when powered off. Gently pull it towards you, you'll need to wiggle it slightly as you do so.

Take a photo of it then.
Didn't see this until I'd taken the photos, and frankly I'm too scared to break anything anyway :lol:

Thanks though!!
geldra wrote: April 6th, 2021, 3:58 pm Got no advice to offer but WELCOME TO THE HOBBY! This type of bullshittery will be your life from now on. 8-)

Ha, thanks... I think??
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by nem »

ChrisBEANS wrote: April 6th, 2021, 4:04 pmOnly place I can imagine the dangling wire may go is onto 'CN301', that you can see in the bottom picture??
That's the one.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by grantspain »

yep cn301, people do not realise how critical that wire is

don't connect the wire with the power on, i am sure you have already figured that out- you will get a lovely massive arc and almost certainly an electric shock
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Right, this thing's a lemon for sure!!!

So, plugged the dangling wire into CN301, and put the loose ground wire under a screw on the bottom of the case.

Put Metal Slug 2 in, and it comes on and looks ok. No sound though, so I go into soft dips to see whether 'demo sound' is in fact on, and it is. Still no sound.

Also, while in the soft dips menu it's apparent that up is down and down is up on the P1 stick (another forum suggests this is something to do with CP grounding).

I add a credit with the service button, and on the character select screen all sorts of odd and garbled sound effects, but not the correct music. However, the screen isn't crackling... so, just to see how bad things are, I start the game and it seems to 'play' correctly, but all the sound is completely knackered, and after a few seconds it crackles again and the screen goes off as before.

It's in a right state. I don't want to mess around with it for fear of making whatever's wrong worse, but right now it's of no use to man nor beast.

I can take a video of the above if anyone thinks it'll be of any value at all, and that it won't cause further damage?? Failing that, I can take a 75% loss and sell it for spares/repair. I'd be very reluctant to do that though...
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by nem »

Aww, don't give up yet.

Reseating the cart could possibly fix your sound issues. The cart slots can be temperamental.

Up and down is easily fixed with just swapping two connectors that plug in to the microswitches on the joystick.

As for the monitor, I'll leave that to grant.
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Re: SNK U4 - Screen crackles and dies (help!!)

Post by ChrisBEANS »

Yeah, the CP stuff is no issue, I’ve built my own fight sticks etc, but the fact the CP isn’t working properly, and the 4 slot isn’t working properly, and the monitor dies after a minute or so all at once...

I could deal with a problem or two, but the whole thing being knackered is pretty disheartening!!

The CP actually confuses me. I had a look and it’s clearly not been touched in years... so surely it can’t have been wired wrong for years?!
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