Diagonal lines appearing in the video (DOA MODEL2A)

[mugen]

Hello, I recently got a DEAD OR ALIVE MODEL 2 A-CRX board.
It’s working well, but I’ve noticed diagonal lines appearing in the video.

My wiring: PSU - MODEL2A - JAMMA harness - SuperGun(CBOX USB v2) - RGB SCART - OSSC - HD60 X (capture)
I confirmed that the PSU output is clean.

Lines are noticeable in the blue sky area.

Has anyone else encounter this issue?

---

I inspected the +5V output from the board.

While the service menu is displayed, I observed slight noise, but there were no visible lines on the screen.

However, when the video board initiates 3D rendering, the noise increases, and the lines become visible.

58Hz frequency seems to be the same as the frame rate of the game.
I guess noise is produced on the video board but I'm not so sure.

Does anyone have any idea how to fix this issue?

 

[biggestsonicfan]

Are you using a video scaler?

 

[mugen]

Are you using a video scaler?

No.

But HD60 X (Video Capture Device) resizes the input when capturing the video.
e.g. 496x384 -> 640x480

I can see lines on both captured image and passthrough video on the display.

 

[biggestsonicfan]

Ah okay, just making sure. I want to say I sometimes see these lines on my m2b board but I am not 100% sure what the cause is. I recognize that JAMMA adapter and it's a good one so it can't be that.

Is the cage sitting on a metal rack? I know you can tie the PSU's earth pin (if it has one) to a cage lid screw to help from interference but I am highly doubting that's the problem.

 

[mugen]

Thank you, so it could happen to other boards than mine.

I'll try to tie the earth pin and a metal rack. I hope it will work.

 

[biggestsonicfan]

Thank you, so it could happen to other boards than mine.

I'll try to tie the earth pin and a metal rack. I hope it will work.

Oh no, don't put it on a metal rack, it just looked like it was on one in the photo you posted.

What's it running on with the JAMMA side? A supergun?

 

[mugen]

I got it. I use a SuperGun with the JAMMA.

PSU - MODEL2A - JAMMA harness - SuperGun(CBOX USB v2) - RGB SCART - OSSC - HD60 X (capture)

 

[biggestsonicfan]

Hmmm, I wonder if the supergun is unintentionally causing this somehow. I don't really have any suggestions to bypass the supergun for video though without something custom.

Edit: Wait, you should be able to wire the Model2 directly to the OSSC I think.

Would you be willing to to give this adapter a try? If you can rig the model2 video to this (this is what I use), you should be able to route the video directly to the OSSC using a VGA cable. If it works I can send you a cable for free that uses the proper connectors between the model2 and VGA board.

Edit2: Oh, I see you are located in Japan. In that case a cheap VGA breakout board on Amazon will work but the colors will look off,but it will confirm if the supergun is causing it.

 

[mugen]

Hmmm, I wonder if the supergun is unintentionally causing this somehow. I don't really have any suggestions to bypass the supergun for video though without something custom.

Edit: Wait, you should be able to wire the Model2 directly to the OSSC I think.

Would you be willing to to give this adapter a try? If you can rig the model2 video to this (this is what I use), you should be able to route the video directly to the OSSC using a VGA cable. If it works I can send you a cable for free that uses the proper connectors between the model2 and VGA board.

Edit2: Oh, I see you are located in Japan. In that case a cheap VGA breakout board on Amazon will work but the colors will look off,but it will confirm if the supergun is causing it.

Thank you so much for your various ideas.

I'd wired PSU-ground, PSU-rack, cage-ground and cage-rack, but there was no improvement.

When I connect other JAMMA boards to my supergun, no noticeable lines appear.
So I suspect that my MODEL2 board has some trouble but I'm not fully confident that my supergun is fine.
And also I'm very interested in connecting MODEL2 and OSSC with a VGA cable. Then I should try this.

 

[mugen]

Finally got the flawless image!

Here are what I did.

Shielding SuperGun from EMI

First, I shielded my SuperGun with aluminum foil.
Diagonal lines were weaken.

I guess radiated noise from the PSU or the MODEL2 cage (or both) interfere the SuperGun.

RGB to VGA adapter
Then I created this RGB to VGA adapter.

Video signal(R/G/B) -> 470uF -> 475ohm -> VGA

Perfect! Diagonal lines have been disappeared!

Also edge noise has been decreased, color tone has been richer.

I'm so satisfied with the result.
Thank you so much for your advices.

 

[biggestsonicfan]

I am very happy to hear you took my advice with the adapter! I am making a model special connector that will have the specs you have listed above if you are interested. It would take less space!



EDIT: Wait, in your photo you have 470uF and 475ohm resistors on the breadboard. The RGB lines already have 470uF (Maybe 470pF actually) caps on the adapter, and the pots should be 500ohm, so you can crank them up to 475, as they appear to be cranked all the way down to 8, lol. You have created a CGA adapter on the CGA adapter where you only needed the additional caps and resistors if you only had a VGA connector.

 

[mugen]

Custom PCB looks nice!

EDIT: Wait, in your photo you have 470uF and 475ohm resistors on the breadboard. The RGB lines already have 470uF (Maybe 470pF actually) caps on the adapter, and the pots should be 500ohm, so you can crank them up to 475, as they appear to be cranked all the way down to 8, lol. You have created a CGA adapter on the CGA adapter where you only needed the additional caps and resistors if you only had a VGA connector.

I am new to electronics so there may be mistakes.
Let me explain a little more.

CGA to VGA adapter
Potentiometers cause a lot of noise on the image, so I set all them to 0ohm. (the adapter was very cheap lol)
Caps on the adapter are bypass caps connected to GND.

Breadboard
I added 475ohm resistors on RGB lines instead of using potentiometers.
470uF caps are decoupling caps to remove DC offsets.

 

[biggestsonicfan]

I honestly believe if all that is absolutely required (including the overkill of shielding your supergun in foil) there is something introducing so much noise in your setup somewhere. I own a JAMMA adapter from the same maker, and experienced none of these issues, even on the worst considered supergun, the Retroelectronik.



This is also the cheap adapter I use, I believe nearly identical component-wise to what you have, with no issue with a direct connection to a CGA converter. However, I do not own an OSSC either, just a GBS-8220 with GBS-Control adapter.

I am now also concerned that the PCB I make will also look awful when used in other environments.

 

[mugen]

Basically, I agree with you.
My CGA to VGA adapter should work.

OK, I found the picture of mine.


It looks like components are almost the same as yours, but, in fact, the quality is pretty poor.

I've measured the resistance of potentiometers and found that range of resistance is up to 200ohm. (not 500ohm)
In short, it's a defective product. (I guess the circuit pattern has some defects too.)
I should have bought the same one as yours. lol

But it just works for me as a D-Sub15 connector.

Just for your reference,
I connected the adapter to MODEL2 directly, set potentiometers to 200ohm and got the terrible image below.
I have OSSC and GBS8200+GBS-control, both result in the same.
When I set resistance to 0ohm, I can get clear but bright image which can be adjusted by potentiometers on GBS8200.

 

[biggestsonicfan]

As I soon realized, this adapter I was making will put too much stress on the filter board's connector. I am revising the design and will incorporate the ferrite ring used by Sega for specific looms.

I will still test this adapter, however, as if this combo of pots and caps do not work, I will need to revise those as well.

 

[rewrite]

I am revising the design

I feel like you could just use longer wires and be fine, no? Let the PCB rest on the cab floor or bolt it to the wall depending on how the Model is mounted (or isn't).

 

[mugen]

Recently I added 1000 ohms resistor to CSYNC line just in case.
This note gave me the idea.
I don't know the best resistance value but 1000 ohm works with OSSC VGA input.

 

[biggestsonicfan]

I feel like you could just use longer wires and be fine, no? Let the PCB rest on the cab floor or bolt it to the wall depending on how the Model is mounted (or isn't).

That's actually how I do plan on testing it, but it's not how I envisioned the design. Also, after installing the pots, calibrating them was a really, really painful process.

I've decided to skip the pots entirely in the next design and just have footprints for metal film resistors. It seems like most people know what they need (and/or are using resistors already) so I may as well go for high quality resistors in a PCB/Enclosure design rather than variable resistor pots.

I got these for $2.52 off Aliexpress and I figure I can repurpose them into better adapters by spinning new boards into them.

 

[biggestsonicfan]

I tried, and failed, lol. Does not work. I am sorry.

 

[RGB]

Have you tried connecting the CSync from the MODEL2 to the VGA HSync pin? In the picture, it looks like it's connected to the VSync.