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

[ChrisBEANS]

I’ve got neither a multi meter, nor any idea how to use one!!

I can certainly get one, and I’m certainly willing to learn. Will any old one from Amazon do, or is there a recommended one I should grab?

[ChrisBEANS]

Also, it’s been suggested that it was a bad idea to turn it on so soon after it being brought inside, and that maybe some condensation was causing a short.

I honestly don’t think it’s been cold enough for that to be it, but anyone got any thoughts on that?

[SuperPang]

Just get a JAMMA volt meter like this. MVS wiring is slightly different to JAMMA but voltage is still wired the same.

https://www.ebay.co.uk/itm/JAMMA-Voltme ... Sw3BJcVbNQ

[sven666]

Just a brief update, I might not actually get to look at it properly until tonight, but I appreciate everyone taking an interest and trying to help and I didn’t want to leave you hanging or to appear that I’d lost interest.

No worries, i will be here untill it runs properly
And like i said dont despair, its a beautiful cab and once we get the gremlin out of it youll enjoy it for many years to come

An intermittent problem sounds even more like a loose connection somewhere.. id just go over everything with a screwdriver to make sure all the terminals on the psu and transformer are properly screwed in.

Keep us posted buddy

[ChrisBEANS]

Just get a JAMMA volt meter like this. MVS wiring is slightly different to JAMMA but voltage is still wired the same.

https://www.ebay.co.uk/itm/JAMMA-Voltme ... Sw3BJcVbNQ

Purchased! Ta!

No worries, i will be here untill it runs properly
And like i said dont despair, its a beautiful cab and once we get the gremlin out of it youll enjoy it for many years to come

An intermittent problem sounds even more like a loose connection somewhere.. id just go over everything with a screwdriver to make sure all the terminals on the psu and transformer are properly screwed in.

Keep us posted buddy

Thanks dude. Really appreciate the after sales support

Hopefully I’ll learn a ton with this cab and in the long term I’ll have it restored to as close to it’s former glory as I possibly can...

[geotrig]

Also, it’s been suggested that it was a bad idea to turn it on so soon after it being brought inside, and that maybe some condensation was causing a short.

I honestly don’t think it’s been cold enough for that to be it, but anyone got any thoughts on that?

It good advise with regards most of stuff like this , while your insulated heated house may not be particularly cold and the odd day out side recently may not have been cold ,but the the cabs route to you may not have been so fortunate ,warehouses, containers ,ships or lorry don't tend to be insulated or heated etc ! so as soon as its on a warmer room some coondesation can build up !
it always best to have a quick run through to make sure nothing has been knocked loose during transit as sometimes even things that dont look like they would come loose before some flimsey item !. although we all as soon as they arrive just want to flick the switch and test it out

I’ve got neither a multi meter, nor any idea how to use one!!

I can certainly get one, and I’m certainly willing to learn. Will any old one from Amazon do, or is there a recommended one I should grab?

its pretty important to have a meter and any old one on amazon etc will do

re the leaving it acclimitise it is best practice , while

[ChrisBEANS]

One big positive, although the picture is slightly wobbly and currently stretched off the screen (all things I know can be adjusted, one thing at a time ) the screen is beautiful!!

I’ve left it running just to see if it stays on... and so far, so good!!

[ChrisBEANS]

H'ok...

So, the short seems to be gone. No idea what was causing it or why. Gone is good, that's what matters.

Keeping this thread strictly to the monitor, I've got a few questions, and an observation...

So the observation is, that the screen developed a really bad purple discolouration on the top corners. Not just a little, but really bad. I know it was mentioned that the degauss button on the front is not needed as the monitor would auto degauss on start up, but it wasn't. I attached the wires to the degauss button, and it sorted it immediately. Great news!

Now I've got some questions on dialling in the screen...

Here's a pic of the chasis (as best I can)




(apologies for what is certainly incorrect terminology coming up!!)
When I got the cab, you can see in the first video that the checkerboard pattern shows that the image was pretty much correct in the top left corner, and was slightly extended past the bottom of the screen and was extended way past the right hand side of the screen...

So, I've had a slight mess about with the knobs, and I've got the top and bottom of the image perfect to the top and bottom of the screen.

I also managed to move the image so that it wasn't so far off the right hand edge, but now it's stretched so that there's some of the right edge and some of the left edge extended past the screen.

There's also some wobble in the picture. Not a massive amount, but there is some.

Any ideas what I do to eliminate the wobble first of all? Secondly, I'm assuming that the 'H-size' is what I need to adjust to effectively shrink the picture in from the sides. However, as per the pictures, there's no dial like there is with the other settings, but instead there's what looks to be a slot for an Allen key. There has to be a reason that this is so different to the other adjustors, and so I thought I'd ask in here first before I just bung a key in it and start twisting!!

Cheers


In other news, I've ordered a bunch of stuff to replace all the controls in the CP, and I've also ordered the JAMMA voltmeter as linked previously, and I've ordered a proper multi meter like a grown up too.
I also have another four slot coming which I'm told works perfectly, so I can see how MS2 works in that.

Feeling much more positive about it all, and again big thatnks to all of you for the help so far!!

[ChrisBEANS]

Also, seems that MS1 and 2, in any slot both have the same weird audio issues. Same issue no matter what slot they're in. MS5 doesn't seem to have any issue regardless of the slot.

Again, not an issue with the carts as they're used on a consolized MVS without issue. Does that point further towards the idea that the voltage may be off? Maybe older carts have a lower tollerance to variations?? I'm just guessing, but someone out there might know?

As above, I have the JAMMA voltmeter coming, so I can at least measure soon. If it is slightly off, can the PSU be adjusted, or will it need to be replaced?



Edit: I removed the fact that MS3 worked without sound issues. I was wrong. In fact it has no sound at all? MS5 plays with what seems to be perfect sound, but has no demo sound even though it is enabled in soft dips...?

[SuperPang]

I'm assuming that the 'H-size' is what I need to adjust to effectively shrink the picture in from the sides. However, as per the pictures, there's no dial like there is with the other settings, but instead there's what looks to be a slot for an Allen key. There has to be a reason that this is so different to the other adjustors, and so I thought I'd ask in here first before I just bung a key in it and start twisting!!

This is a ferrite core and should only be adjusted gently with a plastic trimming tool. They break easily so don't play around with it too much.

[ChrisBEANS]

I might not have to do it at all to be honest...

I’ve managed to adjust the screen so that I can see the blue of the checker board on either side, but just not as much as I should.

In a perfect world I’d pull both sides in a bit, but if I’m likely to cause damage, I can certainly live without those few millimetres...

I’ll google the tool anyway...

[Buddyc]

I got this tool kit. Works great.

https://www.arcadepartsandrepair.com/st ... piece-set/

[SuperPang]

I'd do final adjustments with a game running. Set a 2P game of Garou going.

[ChrisBEANS]

I got this tool kit. Works great.

https://www.arcadepartsandrepair.com/st ... piece-set/

I'm in the UK, but will this do??

https://www.ebay.co.uk/itm/362576075739

I'd do final adjustments with a game running. Set a 2P game of Garou going.

So, here's how it looks on the test screen...



Which I thought was going to be ok, however here's how it looks on MS5 (the ONLY game that seems to run without garbled sound?!?)



You can see in the top left the player avatar/icon thing is pushed off the screen, so I will make the effort to adjust it after all...




Lastly, the slight wobble in the picture is there, and quite evident particularly towards the bottom of the screen, however I barely notice when playing games... Is this just a thing with CRT monitors, or should I be able to adjust it to a perfectly stable image??

Thanks again guys

[cools]

The wobble is more than likely magnetic interference from the internal stepdown.

[Buddyc]

I got this tool kit. Works great.

https://www.arcadepartsandrepair.com/st ... piece-set/

I'm in the UK, but will this do??

https://www.ebay.co.uk/itm/362576075739

I think that will work just fine!

[ChrisBEANS]

The wobble is more than likely magnetic interference from the internal stepdown.

Ah, that makes sense, it’s much more noticeable at the bottom of the screen and pretty much nonexistent at the top.

Worth putting some sort of shielding in there?

https://www.ebay.co.uk/itm/362576075739

I think that will work just fine!

Ordered

[nem]

Is there a narrow / wide jumper on this chassis?

[ChrisBEANS]

Is there a narrow / wide jumper on this chassis?

Certainly not that I’ve seen, but that definitely doesn’t mean there isn’t one!!

I’ll try to take a look over the weekend...

[cools]

The wobble is more than likely magnetic interference from the internal stepdown.

Ah, that makes sense, it’s much more noticeable at the bottom of the screen and pretty much nonexistent at the top.

Worth putting some sort of shielding in there?

The topic has come up time and again, I'm not sure anyone has shielded anything - normally the stepdown is moved to fix the problem.