Help please - getting garbled graphics

Xian Xi

JammaNationX,
15 Year Member
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Dec 1, 2005
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27,748
I still think it's a bad trace from ram to the CPU.
 

Hewitson

Metal Slug Mechanic
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Mar 6, 2008
Posts
2,198
distropia, is the picture on that VGA converter as good as it looks in that pic? If so I reckon I'll definitely be going the VGA route for my next supergun, although its a shame to not be able to play any boards that run at under 60hz.
 

distropia

SouthTown StreetSweeper
10 Year Member
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Apr 28, 2010
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1,075
The VGA converter gives a great still image, but if you're a hardcore gamer, you will notice some small artifacts in moving images or videos. Also in blinking texts.
The converter has an "auto" button for proper syncing with all the boards I've tried.
It works great with any kind of MVS's, CPS2, and pcbs like mortal kombat, the simpsons, raiden II, etc. I've not yet tried it with vertical games.

I've made some superguns with this converter for people asking me VGA out and not caring about artifacts. I always advice customers about that artifacts before building the supergun.

More info: it has RGB pots, you can adjust the resolution, brightness, contrast, size, position, etc. When you turn it on, it shows an annoying big chinese letters (I guess it's the brand) for 4 seconds.
 

Hewitson

Metal Slug Mechanic
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Mar 6, 2008
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2,198
That's a real turn off, that last point you made. Could you possibly take a photo of some of these "artifacts", and do you have any idea if they occur with all VGA converters or just this model?

Thanks
 

Bskull

Crossed Swords Squire
Joined
May 1, 2009
Posts
186
Xian Xi made me VGA box using this exact board. The "artifacts" are hard to describe. It is easy to spot in shooter games like MS due to the fact that there are sprites that are always moving, but the overall quality of the board is pretty good.
 

Bskull

Crossed Swords Squire
Joined
May 1, 2009
Posts
186
Surprised you still remember me after I have been gone for long. :lolz: Anyways, I've been doing other things and searching for another job. I do watch the boards from time to time.
 

distropia

SouthTown StreetSweeper
10 Year Member
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Apr 28, 2010
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Hewitson:
As Bskull said, is hard to describe with a still picture. That's why I took a video for you.

http://www.youtube.com/watch?v=-40gDZey0e8

I only have my phone video recorder, so forgive me about the quality.
Video explanation:
This is a detail of the Samurai Showdown IV intro on a NeoGeo MVS connected to a VGA monitor through this converter. You can see some pixels jumping on the japanese characters as the background moves. These pixels should remain still. The moving background is normal, is part of the intro animation.
The same occurs with the "INSERT COIN" letters.
Take note that this is a zoomed detail (not the entire screen).
The gameplay is not affected. But if you're a hardcore gamer you will notice it.

By the way, Bacteria what's up with your MVS?? We forgot your trouble! :oh_no:
 

bacteria

n00b
Joined
Oct 23, 2010
Posts
28
Not had time to check the board out yet. On the surface of it, can't see any issues with the traces, etc; so i'm going to give the boards a wash in warm soapy water and give a gentle scrub with a toothbrush, lots of rinsing, and a week in a warm cupboard to dry out. Thus, if any bits of debris are on the board this will remove them. I think the board is toast anyway so nothing to lose.
 

Hewitson

Metal Slug Mechanic
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Mar 6, 2008
Posts
2,198
I see what you mean.. I wonder why it does that?

Thanks a lot for going to the trouble of making that video.
 

jew90

Geese's Thug
Joined
Nov 6, 2010
Posts
273
I see what you mean.. I wonder why it does that?

Thanks a lot for going to the trouble of making that video.

Moire and dot-crawl are common under high color saturation with cheap encoders.

Neo video output level is quite high, you could try reducing the levels before they hit the scan convertor to see if this reduces dot-crawl.
 

distropia

SouthTown StreetSweeper
10 Year Member
Joined
Apr 28, 2010
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1,075
Hewitson, you're welcome. I think forums may help people learn one from another.

Jew90, with this converter, there's zero dot crawl and moire (that's mainly caused by interferences and bad shielding in the analog signal). It's another kind of problem. The pixels get "attracted" to the next upper line if that one is moving. Since it is a very complex converter with a processor and memory, I think the problem may be related to internal buffers or software bugs. I guess if it's upgradeable.
I got in contact with the seller and he only told me "press AUTO button for 5 seconds", but the results were almost the same. Also I told about the possibility of erasing that big chinese letters appearing at the boot of the device. He didn't answer...

Bacteria: after the rinsing, I would shake the excess of water and dry it with a hairdryer for 10 minutes at a distance of 15/20cm moving the airflow. If you see my other posts, I've made some advices about cleaning pcb's with water. You have to be VERY careful about that, and NEVER do it if in the pcb can remain a single 0.1 volt. So before cleaning, remove the MVS battery and discharge the capacitors.
 

CZroe

Zero's Secretary
Joined
Feb 5, 2017
Posts
149
Old thread but I landed here from Google after seeing an image just like mine so I thought I’d share the resolution with anyone landing here the same way I did.

Yesterday I had the exact same screen in my “broken” MV1FZ (paid $30) with or without a cartridge. Today I only got the multi color screen like that once but I was getting a very similar black and white (or black and “pink?”) screen. Before I even tried my Neo Diagnostics ROM, I tried dropping in my UniBIOS 3.2 and it fired right up. Switching back to the old BIOS restored the problem. Switching it to an MV1 moved the problem to my MV1. Clearly, the maskROM was faulty. Booting with no BIOS at all showed me the exact same blocky screen.

Easiest fix ever! ROMs were even socketed. Works perfectly as far as I can tell (got wire up some controls next). :)
 
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