MVS scrambled VIDEO Problem! Please help diagnose!

tastysoil · Oct 22, 2009

Seriously, it's seeming like I am not supposed to ever have a working MVS cabinet. I originally got my MVS cabinet and it had sound issues, which was diagnosed as a bad JAMMA board. I got a new board in the mail today, took out the old one and put the new one in and the sound works! ***BUT*** I'm now having video problems! AHHHHHHH

Watch this video to see: http://www.youtube.com/watch?v=GsOx165zJG4

This flickering of the screen happens with both boards & no matter what game I put in--it's something wrong with the hardware but I have no idea what. Seriously, this is making me insane :-(

I'm crossing my fingers someone has an idea of what's causing this. Thanks again...

Dion · Oct 22, 2009

That's an easy fix. Adjust your vertical hold.

tastysoil · Oct 22, 2009

Thanks for replying! stupid question, how do I adjust this? :-) thanks!

tastysoil · Oct 22, 2009

Here is a photo of my monitor--which knobs do I twist? I'm twisting them all and nothing seems to be happening.

kernow · Oct 22, 2009

tastysoil said:
Here is a photo of my monitor--which knobs do I twist? I'm twisting them all and nothing seems to be happening.

Rule #1 - Don't twist knobs that you don't know the function of.

tastysoil · Oct 22, 2009

kernow said:
Rule #1 - Don't twist knobs that you don't know the function of.

Any pointers on what I SHOULD twist?---do you agree with Mitsurugi-w that this appears to be a vertical hold problem?

tastysoil · Oct 22, 2009

tastysoil said:
Any pointers on what I SHOULD twist?---do you agree with Mitsurugi-w that this appears to be a vertical hold problem?

Well, i found the vertical hold and adjusted it and it slowed down the flickering a bit, but it still doesn't fix it. The picture is kind of stretched & rolls over the screen (just keeps flipping)-- Check this new video out...

http://www.youtube.com/watch?v=atCqE2rS-EE

What else can I check? This is really confusing to me because i have not had this problem until today. is this a sign of a monitor that is about to die?

Thanks again for the help with this

tastysoil · Oct 22, 2009

anyone have any other ideas of what I can try (besides adjusting the hold)? Hoping to get to the bottom of this tonight..

Dion · Oct 22, 2009

Now adjust your horizontal hold.

tastysoil · Oct 23, 2009

Mitsurugi-w said:
Now adjust your horizontal hold.

I tried adjusting both the holds, they don't fix the problem. They make it not flip so fast, but it never fixes it.

grantspain · Oct 23, 2009

the sync is not present,check the video input cable on the monitor chassis

Dion · Oct 23, 2009

grantspain said:
the sync is not present,check the video input cable on the monitor chassis

The harness going into the monitor chassis should have 5 wires. Red, Blue, Green and probably grey or white and black. The grey/white one would be the problem. Might be loose at the harness also.

chris1 · Oct 23, 2009

also

Check to see if you have a seperate monitor adjustment board in the cab,.Some wires coming from the monitor to a small pcb with pots on it..In some Candy cabs it's hidden up front...

.sometimes if bumped.or the wire pulled on the plug gets loose into the lil pcb and will cause all kinds of problems,.

just be carefull touching stuff in the back of that monitor..

Aso,run the wires that go from the monitor to the harness,check that the pins are making good contact to the board in the harness.
I had a problem with pins being bent,worn out in a harness that didn't make good enough comtact with the board and I got all kinds of problems..sound etc..I had to install new pind\s in the harness ..I didn't try to bend them but it might be possible.

channelmaniac · Oct 23, 2009

WOW...

That's an old monitor... the pic you sent looks like a Wells-Gardner 4600 series.

It's also missing the plastic retainer that keeps the vertical daughter cards in place.

That monitor suffers from the typical monitor problems of cracked solder joints and bad caps.

Buy and install a cap kit. Check with Bob Roberts or Zanen for the kit.

When doing that, resolder all the interconnects for the daughter boards, the flyback, and all the connectors such as for the yoke.

RJ

tastysoil · Oct 23, 2009

channelmaniac said:
When doing that, resolder all the interconnects for the daughter boards, the flyback, and all the connectors such as for the yoke.

RJ

wow, thanks for the info! This sounds like I might be pointed in the right direction. This sounds like it could be a complicated repair though. I'm not well versed in electrical repair so here is my delema: do I pay a local arcade repair guy to come fix it? I'm not sure what all this connectors are that you said I should repair. Does anyone know of any photo tutorials to help me along on this repair? I know that's a long shot but I'm hoping!

tastysoil · Oct 23, 2009

So, I showed this video of my problem to a local arcade repair guy and he seemed pretty sure that this is a SYNC problem--he thinks that I knocked some wire in there loose and that it should be a pretty easy fix. I tried to find the sync wire that Mitsurugi-w explained above but the inside of my cabinet is a mess---there are wires in it that were never connected to anything when I got the cab (when the video problem wasnt an issue) but i'm not knowledgeable enough to know what shouldn't be connected and what should. Here are some photos, maybe you guys will notice something that sticks out to you:

Inside the cabinet--what a mess!

some wires leading from the monitor spliced into wires going to the jamma

wires leading from the back of the monitor to the jamma

more inside the cabinet

more inside...

Back of the monitor..

I'm going to have a repair guy come out and try and fix this, it'll be expensive though so hopefully with your help I can figure this out! thanks again everyone for your help and suggestions. Let me know if you want any more detailed photos of any particular area, i'd be happy to take them and post them here.

Xionicist · Oct 23, 2009

As was mentioned above, that is a very old monitor.

If it comes to calling out an arcade repair guy (they always overcharge if it isn't their equipment), I would instead look into just getting a new damn monitor in there. Trust me, unless the guy is a friend, it will be cheaper and more reliable in the long run.

This is probably a sync issue, but I'm not familiar at all with the 4600 series. I have a 4903 in a different game, but I don't know it well enough to diagnose this specific problem. I'm fairly certain the the issue could be resolved by doing a complete cap kit on the monitor, which information can be found all over the place to learn how to do. One rite of passage of owning an arcade game is learning how to fix stuff like this. It can be a pain in the ass, but once you do it, you'll be able to handle the inevitable problems that come from owning a 20 year old (or more) piece of electronic hardware.

What I would suggest is going over to the KLOV forums at http://www.klov.com/ and taking a look through their monitor repair section to see if anyone has had the same problems with a 4600. If you can't find anything, post a question and be VERY SPECIFIC about the model and nature of the problem. They have some good monitor techs over there, but they don't like having their time wasted.

Xian Xi · Oct 23, 2009

Read the jamma pinout and trace the sync wire from the board to the monitor.

Blur2040 · Oct 23, 2009

Check this link:

http://www.therealbobroberts.net/slanted.html

The whole Bob Roberts page is full of solid advice. Do what it says. Be careful though. Seriously. High voltage and such.

I had a problem with mine that caused the picture to go sideways...the hidden horizontal adjustment fixed it. It wouldn't explain the vertical rolling though. Might be worth a look anyway.

Edit 2: I guess I too am leaning towards you yanking on something that messed with the sync connection when you took out your first board. I'd say that you should first check the sync pin at the jamma harness (seems like the most likely place for something to get screwed up)...and then work back.

grantspain · Oct 23, 2009

thats some seriously bad wiring on the cab,i reckon the sync will not read continuity to the jamma connector -those push in connectors are really crap

ReplicaX · Oct 23, 2009

Personally I'd just wire in a new harness, but thats me.

Dion · Oct 23, 2009

Did the video on the first board work good? Does it not work now? I'm going to check some schematics when I get home and see which wire is the sync wire. Or you could fine the video sync wire on the jamma harness and follow it up to the monitor.

But it could just need a cap kit also....

grantspain · Oct 24, 2009

i am guessing this but i am sure the sync is on the bottom 2 pin plug,that plug goes onto a 3 pin header-i bet moving that plug to the next pin will have an affect

incrediblehark · Oct 24, 2009

grantspain said:
i am guessing this but i am sure the sync is on the bottom 2 pin plug,that plug goes onto a 3 pin header-i bet moving that plug to the next pin will have an affect

Thats what fiixed my monitor issue

tastysoil · Oct 24, 2009

Mitsurugi-w said:
Did the video on the first board work good? Does it not work now? I'm going to check some schematics when I get home and see which wire is the sync wire. Or you could fine the video sync wire on the jamma harness and follow it up to the monitor.

But it could just need a cap kit also....

Hey Mitsurugi-w--- well, originally the video worked fine on the first board, but the audio was totally messed up. Fast forward>> I end up getting a new board to fix the audio issue and when i installed that and turned it on the video was totally messed up (like what we've been talking about) but the audio was fixed. >> I installed the old board to check and see if it was a problem with the new one, but nope, i have the same video issue with the old board (confirming that it's a problem with the jamma harness or the monitor) After messing with the horizontal and vertical hold all night i realized that it was a possibly something that came loose while I installed the new board.

I'm not sure what to look for in the cabinet due to how this cab was wired up---whoever wired this up didn't care about any order whatsoever. Makes it 100% confusing for someone trying to learn to have any idea of whats what.

Does anyone know of any tutorial videos or photo sites dedicated to cap repairs?

MVS scrambled VIDEO Problem! Please help diagnose!

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