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

[thegreathopper]

Good point, I don’t think so but don’t chance it.

That post was too confusing so have edited it. It’s been a long day,!

[ChrisBEANS]

Already bought the multi meter... just no idea how to use it properly

Managed to measure some voltages, but that’s the current limit of my ability!!

[ChrisBEANS]

Good point, I don’t think so but don’t chance it.

That post was too confusing so have edited it. It’s been a long day,!

I’d just come back to re-read it!!

What I understood was that the multimeter I have should be able to tell me the resistance between pins 11 and M.

I should do this without the JAMMA/MVS edge connected to anything...

Due to the difference in wiring between JAMMA and MVS, the result should tell me one way or the other... right?




However, just remembered, in the hardware test menu in the speaker test, you can select ‘left’, ‘right’ and ‘centre’, and sound does indeed come from the left or right speakers individually when selected.

As JAMMA is mono, that must confirm that this cab is MVS wired... right??

(Thanks again for all the help and interest!)

[nem]

Measuring DC resistance with speakers can give you false positives, so I wouldn't even bother. For instance if I measure resistance between 10 and L on my MVS wired Neo cabinet, I get a full 8 ohm load. My meter also shows continuity between 10 & GND and 11 & GND.

As JAMMA is mono, that must confirm that this cab is MVS wired... right??

More than likely, yes.

[thegreathopper]

As JAMMA is mono, that must confirm that this cab is MVS wired... right??

(Thanks again for all the help and interest!)

[thegreathopper]

Measuring DC resistance with speakers can give you false positives, so I wouldn't even bother. For instance if I measure resistance between 10 and L on my MVS wired Neo cabinet, I get a full 8 ohm load. My meter also shows continuity between 10 & GND and 11 & GND.

Presumably a bit less resistance though? about 4 - 6 Ohms as you would be measuring each speaker rather than both in series.

[nem]

If you measured 10 & GND or 11 & GND, yeah.

On my Neo the grounds aren't bundled together, so you have to hunt down the correct ground wire that goes up to the speakers. Mine was at the very end, 28 or f, can't remember.

[ChrisBEANS]

Not much of an update today... there’s a puppy who doesn’t appreciate the risk of an open and powered up arcade cabinet getting in the way

However, chased up the external step down today and it’s looking good that I’ll have that early next week.

I’ll be taking delivery of a Blast City on Monday, and the Electrocoin six slot on Wednesday. (Also coming with a four slot board).

All going well, next week I can eliminate the wobble with the external step down, and assuming the four slot is in good order I can transplant that into this cab, and then find someone to repair this one with the sound issues

I’m anticipating big progress soon!!


Got an idea for the aesthetics on this cab too, just not sure how people will feel about it

[thegreathopper]

Got an idea for the aesthetics on this cab too, just not sure how people will feel about it

Easy answer to that one, If it’s not stock they will hate it!

[ChrisBEANS]

Yeah, figured...

All the stickers were repros and weren’t very good either, so they’re already gone.

CP’s a nice repro, I’ll keep hold of that of course, and the coin slot has been riveted closed, so that needs sorting out one way or another anyway...

It’ll be pretty simple, and worst case, I’ll simply reapply more repro stickers and have it looking stock again.

I’m not doing anything dramatic or destructive to it

[nem]

All the stickers were repros and weren’t very good either

[...]

and the coin slot has been riveted closed

[ChrisBEANS]

All the stickers were repros and weren’t very good either

[...]

and the coin slot has been riveted closed

Yeah, the blue stripes down the side of the monitor were slightly too wide, so the edges were sticking up in places, and the ‘MVS’ badge was off centre and at a bit of an angle.

You could only really tell when you sit in front of it, but it would have bugged me to leave it

I’ll chuck up a picture of the coin slot in a bit.

Same thing with the memory card slot and headphone jacks.

In a perfect world I’d replace the coin slot (cosmetically, no need for a replacement coin mech) and wire the ‘coin return’ button as a coin in button.

I’ve had a really good look around though and can’t find any coin slots, so I might have it patched up and then have a ‘coin’ button installed in its place.

Going to replace the memory card module...

[sven666]

CP’s a nice repro, I’ll keep hold of that of course, and the coin slot has been riveted closed, so that needs sorting out one way or another anyway...

It’ll be pretty simple, and worst case, I’ll simply reapply more repro stickers and have it looking stock again.

I’m not doing anything dramatic or destructive to it

uuuh bro, the CP is a NOS original, as are the buttons, the stickers were spot on size and colour of originals..

anyways the sound is wired correctly, ive had this cab up and running for months before i sold it, im not saying the 4slot couldnt be broken but it seems strange some carts work and some dont.
If i were you id wait untill you get that spare 4slot to test it before you start rewiring the cab..

[ChrisBEANS]

Ah! Makes sense it’s NOS! It’s immaculate so I’d assumed it was a repro...

The buttons are just a personal preference thing, I’m not chucking or destroying things, just going to change things up a little.

If it looks crap nothing original will be lost or damaged and all I’ll need to do is reapply the repro stickers.

I’ll wire pin F up to the 12v on the PSU as it’s not getting power in any case, and I won’t be rewiring anything else.

Looks like the other four slot arrives on Wednesday, so I should be able to test it on the new cab and then try it out in this bad boy.

Assuming this one does have issues, does anyone recommend someone in the UK who repairs them?


Hope you don’t get the wrong impression, I’m not complaining about the cab, I expected things to need doing, I’m just trying to get it to a position where I can simply sit down in front of it and play some games.

Getting it fixed up is half the fun

[sven666]

bro the cab is yours you may do with it as you please, ofcourse, I also understand the screen and sound issues are frustrating as hell, it is for me too as it kinda reflects back on me as a **** seller, really wish I could just pop over and fix it for you.

but letting one negative create more negatives and tearing the cab up in all different areas at once is not the way, youll just end up with a broken mess you hate.

give it a rest and try the new 4 slot when it comes, if the one I sent is proven faulty well work something out.
theres a great PCB repairman in the uk whos name escapes me (i think he used to go under r-typer?), hell suss it out im sure.

Im convinced once the gremlins are out of it and you take a step back youll realise the cab is a gem and youll fall in love with it again

[ChrisBEANS]

I fear I have come across wrong and given the wrong impression.

I’m not unhappy with the cab and I’m certainly not unhappy with you as a seller. I actually really appreciate the continued support, you’re not obligated and I think that reflects well.

I totally expect there to be issues with something like this that’s 30 years old.

The short was weird, clearly not something that happened before the sale, and it went away without me doing anything, so no issue there.

Screen calibration is to be expected, and it’s 99% there already. No problems. If I can get time away from this puppy today I’ll probably dial it right in.

The fact pin F was wired to something for a previous MAME usage is no issue, I’ll simply wire that to the 12v on the PSU and it’s all sorted.
Diagnosing and sorting that was fun! I’ve never used a multi meter or soldering iron before, and I’m enjoying the learning.

The appearance of the cab is a preference thing, and I’ll absolutely be looking after everything original. Nothing will be lost.

The replacing the controls I was always going to do. I’ve built and modified fight sticks for years, and I know what I like to use is all.

As for the four slot, again, I expect things to go wrong with 30 year old electronics. If it’s the case that I need to get it repaired, I’ll get it repaired. It’s all good.

I’m having fun learning with this cab, and I’m really looking forward to getting it sorted. It’s an adventure!

No problems or complaints, I’m just being very careful to get advice on everything I’m doing so that I don’t damage something that can’t be replaced.

There will only ever be fewer of these cabs in the world, never any more, and I respect that.


When all this COVID lark is done and dusted, get yourself over for a game of Metal Slug, and I’ll buy you a pint

[SuperPang]

Vectorglow is the repair guy but he doesn't touch MVS.

[geotrig]

If you are local to someone maybe they could test the 4 slot for you in there setup

[ChrisBEANS]

Getting two more cabs this week in any case, one MVS, and a Blast City which I’ve also got an MVS to JAMMA adapter for.

It’s all good.

I’ve also got a single slot that I could put in the U4 today, but I can’t go anywhere near an open cabinet with my dog constantly at my feet

[ChrisBEANS]

Progress!

I’ve wired F to 12v, so that’s now sorted.

Same issue persists with the sound on the 4 slot, however, using a JAMMA to MVS adapter (JNX) I’ve tried Metal Slug on the machine and it sounds perfect!

Only issue, which is a little amusing... there’s a volume slide on the 4 slot. There is no volume slide on the 1 slot, and it’s bloody loud

Edit: there’s a volume knob on the one slot