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

For monitor related issues
Post Reply
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

I don't expect anyone to recognise what's going on here without being able to look at the cab, and I've no idea where all the other wires trace back to... but here's where the wire for pin F (with no power) goes...

Image

All together in tape. The wire from pin F is yellow, and the other two in at the same end are black and orange.

Coming out of the other end of the bundle, a black and a brown wire...?
User avatar
geotrig
Potato!
Posts: 7506
Joined: December 5th, 2008, 1:14 pm
Location: ._.
eBay: ._.

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

Post by geotrig »

Yeah you can use the multi meter to measure voltage at t he ps
I'd guess the wire that's not getting power had got disconnected under the tape. You can just twist these around each other if there is a corresponding wire to get a connection again.
Edit:
Just seen you pic if you can trace any of those back to the 12v just connect it to the yellow one , blacks could be ground, you can use your continuity test to try and see where they all go and label according ly
Image

<trk>:I remember catching a big fat one and my friend said "throw it back in, that one already tastes like wood"
User avatar
sven666
Posts: 500
Joined: August 28th, 2008, 8:03 am
Location: Hisingen SE
eBay: sven-666
Initials: JNX
Contact:

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

Post by sven666 »

A previous owner ran a mame setup in the cab thats proboably why the cable is split, it runs to a connector of some sort i think?
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

So might it make sense to simply disconnect that wire from pin F, and run a 12v wire from the PSU straight to the JAMMA (MVS) edge??
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

thegreathopper wrote: April 13th, 2021, 2:34 pm 12V is used for sound as far as I know, you could always put a jumper cable on your jamma edge connector to get +12V on the correct terminals.
You mean simply use a short wire to bridge F and 6? And I assume remove/disconnect the wire that is currently attached to F?
User avatar
thegreathopper
Geese's Bodyguard
Posts: 1690
Joined: August 17th, 2008, 6:56 pm
Location: London
eBay: thegreathopper
Initials: STV

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

Post by thegreathopper »

ChrisBEANS wrote: April 13th, 2021, 8:07 pm
thegreathopper wrote: April 13th, 2021, 2:34 pm 12V is used for sound as far as I know, you could always put a jumper cable on your jamma edge connector to get +12V on the correct terminals.
You mean simply use a short wire to bridge F and 6? And I assume remove/disconnect the wire that is currently attached to F?
Yes simple as that, you got a soldering iron yet? it’s essential when you own cabs. :D
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

thegreathopper wrote: April 13th, 2021, 9:38 pm
ChrisBEANS wrote: April 13th, 2021, 8:07 pm
thegreathopper wrote: April 13th, 2021, 2:34 pm 12V is used for sound as far as I know, you could always put a jumper cable on your jamma edge connector to get +12V on the correct terminals.
You mean simply use a short wire to bridge F and 6? And I assume remove/disconnect the wire that is currently attached to F?
Yes simple as that, you got a soldering iron yet? it’s essential when you own cabs. :D
I thought I was being a grown up when I got the multi meter. A soldering iron is more grown up still...
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

Ah man :problem:

I got home all excited to bridge the pins. Had my spade connectors at the ready, and the bloody thing’s soldered :wtf:

Looks like I’ll have to order a soldering iron, and it’ll be a couple of days before I can see if that works...

Edit: Soldering iron ordered, same day delivery... whoop!!
User avatar
thegreathopper
Geese's Bodyguard
Posts: 1690
Joined: August 17th, 2008, 6:56 pm
Location: London
eBay: thegreathopper
Initials: STV

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

Post by thegreathopper »

Practice first on some spare cable, you don’t want to over heat-melt the Jamma connector. It’s not easy to damage it be careful.

You will need some decent lead solder 60-40 fine and some flux.

Like this

https://uk.rs-online.com/web/p/solder/7568904/

And this

User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

See, this is where I realise how out of my depth I am...

Here's what I've ordered:

Image
(arriving today, God bless Amazon Prime!!)

I've zero clue what flux is, no clue what 'tip tinner' is, and I was under the impression that leaded solder was a thing of the past?

I only want to bridge two pins :lol:

Edit:
Consider me educated (slightly)
User avatar
thegreathopper
Geese's Bodyguard
Posts: 1690
Joined: August 17th, 2008, 6:56 pm
Location: London
eBay: thegreathopper
Initials: STV

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

Post by thegreathopper »

Leaded solder is a thing from the past as is Metal Slug and Neo Geo MVS U4 cabs, hence old solder for a old jamma connector.

I am sure that solder will work but it needs more heat to melt so be careful, nice soldering iron by the way.
User avatar
SuperPang
Master or universe
Posts: 11012
Joined: August 16th, 2008, 2:45 pm
Location: UK
eBay: *_*
Initials: JOE
Contact:

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

Post by SuperPang »

I honestly wouldn't attempt this until you've ruled out the 4 slot as being faulty.
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

Oh... really?

Even though it’s confirmed that pin F isn’t getting 12v?
User avatar
nem
Needs a custom rank
Posts: 2768
Joined: August 17th, 2008, 6:59 pm
Location: Finland

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

Post by nem »

It likely won't make a lick of difference. F and 6 are bridged on the motherboard. I can't see the amp pulling so much current that it will matter if you have one or two wires going into it.

(doesn't mean you shouldn't fix it, because you should)

EDIT: wait a minute, how is it that it's not showing any voltage for you then? I have a 4-slot motherboard here and if put the meter leads on opposite sides on pin (ie. 6 and F), the multimeter will beep on continuity mode / diode test. Yours doesn't?
Last edited by nem on April 14th, 2021, 1:33 pm, edited 1 time in total.
User avatar
SuperPang
Master or universe
Posts: 11012
Joined: August 16th, 2008, 2:45 pm
Location: UK
eBay: *_*
Initials: JOE
Contact:

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

Post by SuperPang »

Has anyone said categorically that it's the cause of your audio issues? If so, then you have to bite the bullet and go for it. Honestly I have no idea if some MVS games require both 12V lines for audio. Seems weird but entirely possible.

All I'm saying is that if you've never soldered before, don't do it until you're absolutely sure you have to.

EDIT: What nem said.
User avatar
ChrisBEANS
moneyspendingexpert.com
Posts: 859
Joined: November 14th, 2020, 8:21 pm
Location: A Box
eBay: chrismartinlewis
Initials: BNS

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

Post by ChrisBEANS »

So, with the multimeter, black probe on a ground pin, and red probe on pin 6 shows 12.1v.

Black probe on ground pin and red on pin F shows nothing.

That’s on the JAMMA (MVS) edge.

I’ve since physically followed the wires back, and 6 goes to the PSU, F goes to the taped bundle pictured above.

It’s been said in this thread that the 12v are used for sound, and it seems the only issue is sound, so it made sense.

I’m totally open to guidance though!!!
User avatar
thegreathopper
Geese's Bodyguard
Posts: 1690
Joined: August 17th, 2008, 6:56 pm
Location: London
eBay: thegreathopper
Initials: STV

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

Post by thegreathopper »

Its a 30 second repair, if its not showing on both 12v terminals it cannot be linked on the MVS motherboard.. of course your pins could be bent on your Jamma connector. :-o

Have a look at the 2 bits that grip the MVS board on the 12V connections of your Jamma connector and post a pic.
Last edited by thegreathopper on April 14th, 2021, 2:03 pm, edited 1 time in total.
User avatar
nem
Needs a custom rank
Posts: 2768
Joined: August 17th, 2008, 6:59 pm
Location: Finland

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

Post by nem »

Nevermind. I'll grab a pic. Wait a minute.
User avatar
thegreathopper
Geese's Bodyguard
Posts: 1690
Joined: August 17th, 2008, 6:56 pm
Location: London
eBay: thegreathopper
Initials: STV

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

Post by thegreathopper »

ChrisBEANS wrote: April 14th, 2021, 1:56 pm So, with the multimeter, black probe on a ground pin, and red probe on pin 6 shows 12.1v.

Black probe on ground pin and red on pin F shows nothing.

That’s on the JAMMA (MVS) edge.

I’ve since physically followed the wires back, and 6 goes to the PSU, F goes to the taped bundle pictured above.

It’s been said in this thread that the 12v are used for sound, and it seems the only issue is sound, so it made sense.

I’m totally open to guidance though!!!

When you are measuring you need to have the Jamma connector connected to prove Nem's point about the 2 being linked on the MVS 4 slot.

Either way you do need your Jamma connector wired up correctly so the soldering iron will be helpful.
User avatar
nem
Needs a custom rank
Posts: 2768
Joined: August 17th, 2008, 6:59 pm
Location: Finland

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

Post by nem »

measuring_voltage.jpg

This is how you measure voltages. The motherboard needs to be connected to the jamma connector. Voltages aren't meaningful if the PSU isn't under load. Both 12V pins will show voltage, because the pins are bridged on the motherboard.

Check your +5V again.
You do not have the required permissions to view the files attached to this post.
Post Reply