Jump to content
Due to a large amount of spamers, accounts will now have to be approved by the Admins so please be patient. ×
  • 0
IGNORED

CRT Monitor display with wiggly lines


0xce

Question

I have recently got a CRT monitor up and running.

 

Previously I have this converter board which ran my Jamma board on a LCD screen:

 

adapterboard.jpg

 

The CRT monitor has a VGA cable wired (and taped) up. I am trying to plug the VGA cable from the CRT in to the adapter and I have the following results below. If I use the CRT controls, the wiggles resize and move with the screen when making adjustments.

 

I guess my question is that 1) Has anyone seen this before? and 2) Could it be the adapter causing this, meaning should there be a cable that goes from the Jamma RGB cable to the CRT?

 

Here is what I get:

 

IMG_0294.jpg

 

IMG_0295.jpg

 

IMG_0296.jpg

 

IMG_0300.jpg

 

IMG_0302.jpg

Link to comment
Share on other sites

22 answers to this question

Recommended Posts

  • 0

Is the CRT 31khz or 15khz?

 

If it's 15khz, no need for the adaptor now. Ditch it and hook-up the board directly. It may require some rewiring, but there's no need for the adaptor anymore if you're going to run a 15khz CRT.

 

Also, the VGA cable wired to the monitor may not be VGA, it could just look like one. If it's a 15khz monitor, it may just be a DB-15 plug that has been wired to take RGB-sync and ground.

Link to comment
Share on other sites

  • 0

Hi Namastepat

 

That sounds like the best option, I'm embarrassed to admit I do not know if it is 15khz or 31khz and on top of that I don't know how to find out.

 

I think you are spot on with the cable though. I have removed it and taken a couple of shots of the cable and connector.

 

It appears to go in this order:

 

1) Red

2) Red Ground

3) Green

4) Green Ground

5) Blue

6) Blue Ground

7) H\V ?

8) V ?

9) ?

10) Ground

 

IMG_0317.jpg

 

I figure I should be able to wire 1, 3, 5, and 10 to the Jamma video connector.. but which one should be 'sync' ? (which is a white wire from the Jamma video connector)

 

 

And here is the current connector:

 

IMG_0318.jpg

Link to comment
Share on other sites

  • 0

When it comes to specific wiring, I will pass it over to people who know more than I do.

 

Basically, take a photo of the monitor chassis with a model number and other stuff visible and @Jomac will likely be able to ID the chassis. Or you can go to his website here and see if you can ID the chassis from the photos. That will let you know if it's 15khz or 31khz.

 

http://www.jomac.net.au/services/monitors/

 

The rewiring is beyond my skills, but someone on here will be able to let you know what needs to go from the JAMMA harness to the connector.

Link to comment
Share on other sites

  • 0

No problem and thanks heaps for info you have provided.

 

I would say it looks like it is a Ducksan 1301 Series. I have found a schematic which looks like it matches too, and according to this:

 

Pin 7 = H Sync

Pin 8 = V Sync

 

Ducksan Schematic.PNG

 

 

And the Jamma Video connector has the following:

 

RED

GREEN

BLUE

GROUND (black)

SYNC (white)

 

JammaVideo.PNG

 

Which leads me to the question about which Sync should be wired up to this connector (V Sync or H Sync) ?

 

 

 

I still can't find whether it is 15 or 31 khz but here are the labels from the monitor:

 

ducksan.jpg

samsung label.jpg

Link to comment
Share on other sites

  • 0

I wired it directly, using sync H and unfortunately it didn't make any difference, the display remains sqiggly - I have noticed the squiggles change depending on what is on the display at the time. I managed to get hold of another board, (different game) and with using the same wire harness, there was no display distortion.

 

The game board I am using with the monitor issue is Point Blank. Now I am wondering if this Point Blank requires a specific monitor to run on?

 

I will try it with a different power supply tomorrow but I have my doubts that will change anything.

Link to comment
Share on other sites

  • 0

I've seen a similar wavy image problem myself. It turned out to be the video ground. According to the Jamma pinout, video ground is pin 14 on the components side but some boards use pins 1 or 2 as the video ground.

 

If your Jamma harness has video ground wired to pin 14 but your board's video ground is coming from pins 1 and 2 then your monitor ground isn't connected to the board's video ground. I picked up on this when trying out bootleg boards, another facet of penny pinching. If pin 14 on your board goes nowhere, there's your answer.

 

Solution: solder a wire between pins 14 and 1 or 2.

Link to comment
Share on other sites

  • 0

Hi guys, hope you all had a great weekend.

 

rocky2 / con: That sounds REALLY interesting and promising. I took a look at pin 14 on the Jamma wiring and it did not lead anywhere as expected. I soldered pin 14 to pins 1 & 2 - checked continuity which checked out. Unfortunately there wasn't much difference - possibly improved but I'm not 100% sure.

 

An additional note is that the wavy effect happens mostly where there is text.. like the scoreboard appears blank and not really wavy then the text for the players' results appears and the wavyness appears across the screen where the text appears. Not sure if that is a clue. I have marked the following image with green markers to indicate what I mean:

 

(I had to resize due to hitting my upload quota)

 

text wobble.jpg

 

But to give an idea, the wobble isn't really visible before the text appears.

 

 

Another suggestion was to wire the V Sync and the H Sync, but unfortunately this makes the screen much worse.

Link to comment
Share on other sites

  • 0

Thats actually a good question. I believe it may to do with text - looking at the following picture there is an image of a white flag which is not affecting the horizontal area - but perhaps that is a 'different white' to the text.

 

[ATTACH=CONFIG]132468[/ATTACH]

 

And to add to that I have a Tekken 1 board which runs on this screen without any of these issues.. I really hope it is not a board problem as I wouldn't have a clue where to look!! :unsure

Link to comment
Share on other sites

  • 0
I have a Tekken 1 board which runs on this screen without any of these issues.

 

OMG i wish you'd posted that first :)

 

So, it's a horizontal deflection issue to do with different levels on the HV (i think). I see the chassis has a horizontal hold pot; give it a twist. Can't hurt.

Link to comment
Share on other sites

  • 0

Sorry I thought I had mentioned that :redface, I had a mess with the Horizontal Hold and I could only make things worse so I have reverted it back to its original position.

 

I may have some more clues:

 

The issue also happens in the Service Mode menu, where the screen is black and the text is white.

 

Interestingly if I remove any one of the R/G/B channels the display is normal (but without the colour from the channel) it doesn't seem to be any single channel causing it from what I can tell - only when all three are connected it goes crazy on the areas with text

Link to comment
Share on other sites

  • 0

So, let's see if i can summarise where we are now.

 

You've left the converter board you used to use with your LCD right out of the circuit now, yes? And the Tekken 1 board you have syncs up and looks fine, nothing wrong with the picture. But the jamma multiboard gets these issues you posted pics of.

 

Is the screen stable with the distortion, not rolling or moving much if at all? Or is the whole image rolling or moving/vibrating somehow?

 

Have you tried leaving the distorted image on the screen and simply turning the overall brightness & contrast or screen pot on the flyback down to see if that affects things?

 

You say you tried wiring H- and V-sync to the board. Does the chassis have any way to switch modes from C-sync (which will go into the H-sync pin) to separate +/- H- and V-sync, any switches or toggles? Admittedly this is not likely to help, as without V-sync the picture would roll vertically, and without H-sync all you get is a mess. Anything set up for Jamma should be delivering C-sync to begin with, as i'm sure the Tekken 1 board would be.

 

Do you have any other jamma video sources to try? And where is this service mode you mention; is it part of the Ducksan chassis, or built into the jamma multiboard?

Link to comment
Share on other sites

  • 0

Hi and thank you again for taking time to help me out it is really appreciated

 

Summary: That is correct there is no video converter board in use. The Tekken 1 board looks fine yes. The other board is a Point Blank board (the one with the issue).

 

The screen is stable but the distortion wiggly lines move rapidly sort of left and right, only in the rows where the text graphics tend to be.

 

I have messed around with the monitor controls but it doesn't help, the problem stays in the relative position to the screen; so if I stretch and move the image the distortion also stretches and moves.

 

I have tried combining the H and V sync together with the c-sync but that made it worse and I can't see anything that allows me to change between H / V on the monitor itself, although I will take another look to double check. Its as though the screen has H and V but the Jamma boards only have one sync?

 

The service mode I mentioned was the game's service mode screen, on the board there is a little switch that activates it.. it allows you to configure coins / test and calibrate the gun - nothing that has video options though apart from a few test screens with colours and lines.

 

I think I should see if I can get someone to test my board with their monitor to see if the same things happen. This should confirm whether it is a problem with the board itself. Might take a while though!

 

I'll see if I can get a video of it. I have made one on my iphone but it saved like 150MB of data which I won't be able to upload.

 

Thanks

Link to comment
Share on other sites

  • 0
I think I should see if I can get someone to test my board with their monitor to see if the same things happen. This should confirm whether it is a problem with the board itself.

 

Yes, this is probably the next step. And find another board to test on your monitor, if you can. Beyond the pinouts, Jamma can be variable, and the video from one board might upset a particular monitor. Two different boards working fine elsewhere though, would probably point to a chassis issue.

 

It's never easy diagnosing at distance, but hopefully we haven't overlooked something simple :)

Link to comment
Share on other sites

  • 0

Well the monitor died when powering it up today, I'm not sure if it was on the way out - I was messing with the settings previously - I had a plan of seeing if I could use the checkered test screen and mess around with each colour channel individually - chances are it wouldn't have helped. Interesting one of the test screens had 1/4 size bars of faded Red, Green, Blue, and White. now on that screen everything looked fine!

 

Anyway the reason I am posting this is to offer the monitor to anyone that is interested in it for free. I believe a capacitor popped when I hit power and I really don't want to mess with the electronics of something such as a monitor. Not only that the amount of time I have spent messing with it has already been way too much.

 

I am located in northern suburbs of brisbane if anyone reading is interested. No obligations but if someone wants it and happens to have a jamma CRT setup they wouldn't mind testing my board on I would really appreciate it :) I really wanted to rule out issues with the board itself; then I can ponder getting another monitor in the future.

 

The screen has burn in, which wasn't too noticable when displaying an image. it is 19" - anything else wanting to know about it feel free to ask.

 

Thanks to all the people trying to help me through this, what a great site and community!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...