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Street Fighter 2 bootleg board help need to fix it


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Hello Guys

Have this old SF2 bootleg board that was working normaly, but stays to much long period without use, now i decide to give it a try on my multi-game cabinet, but the board now is acting strange, like it was out of sync (jumping sometimes) and all colors messy, any one have seen such issue like that.

OBS: Replace some caps since i dont have and schematics, i think those caps bellow to audio section think they will not interfering in video section, and arcade monitor is fine, because i use it with a regular PC with 15khz output and works fine, the problem is the sf2 board itself

 

Here is the video, and photos from the board: https://photos.app.goo.gl/BaAUY9bj4cMSUF758

 

Any help will be very much aprreciated !

Thanks

Marcos

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Hello Womble

Thank you so much for your help !

Man do you think is only just that, lol, ,because the gnd from jamma conector 1 to 2 both sides are wired on the gnd power unit.

 

Do you think if i crab the gnd from 27 and 28 jamma section both sides could be a test point ?

 

Thanks a lot

Marcos

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Your monitor needs a connection to that pcb ground too, it’s called video ground but it is almost always the same as system ground. The monitor needs red, green, blue, sync and ground hooked up. Without it the colour and sync signals lack a reference point, so you get unstable sync and weird colours as they drift and interfere with each other.

 

All grounds on the Jamma connector should be common (connected to each other).

 

But yes, probably just that.

Edited by Womble
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Hello Womble

Thanks again !

The video gnd is already wired too, very strange, well will try to get gnd from pins 27 and 28, just a note on the 1 and 2 pins both sides solder and part, does it need to be all conected each other i mean, because if i remember well i wired 1 + A them 2 + b into another wire, do you think those 4 have to be all toghter ?

 

Thanks a lot

Marcos

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Actually, I can see the problem in your photos, some bootleg boards have this issue, it’s that pin 14 doesn’t go anywhere on the board, it’s just a pad. So even if you have the harness wired up correctly to that pin you lack a video ground connection to the monitor.

 

On your harness just run a wire from any of the other ground pins to pin 14 and it will achieve the same thing.

 

The pcb will connect 1/2 and A/B together anyway, it’s just the board’s video ground pin that doesn’t connect to the others on this pcb .

 

It’s a board design fault, or a daft design decision they made.

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Hello Womble

This is the good news post !

Thank you so much for your help, you were right the tab 14 has no gnd connection at all, it leads to no where, made a jumper from 28 pin to 14 and bam ! SF2 returned from the dead !

I updated the google album with some nice sf2 shots: https://photos.app.goo.gl/BaAUY9bj4cMSUF758

 

Thanks to you my this board will be use in a new project in mind, will try to use it with a regular tv Philips RGB modded: https://photos.app.goo.gl/ROlDzMpabIOwCrV42

will see if it will work !

Only thing i noticed comparing the footage with my pc runnig grovymame + crt_emudriver outputing 15khz, the board shows a more dancing screen them the pc, maybe the issue is with arcade monitor, or do you think there´s something on the board that can control the frequency or something like that.

 

Thanks a lot

Marcos

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Great news, glad I could help.

 

Not sure what you mean by "dancing screen" so its hard to say. Without seeing it I would say your most likely options are going to be 1) the monitor 2) a power issue.

 

I'd check the voltage levels across the PCB, measure it on an IC as far away from the JAMMA connector as possible. If it is around 5v you are fine, if it is rather low then there you should check the voltage at the JAMMA connector side of the board. If your 5v and ground wiring between the PSU and the PCB is too thin then you can get a lot of voltage loss in the wiring, so even if the PSU is reading 5V you may only get 4.7 at the board, and 4.3 at the back. That can cause video or graphics issues.

 

Voltage drop across the board is normal, you just need to give the board enough that the natural drop doesn't leave remote areas too low.

 

If your harness is dropping more than half a volt you should add more runs of wire to it.

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Hello Womble

You were right again ! Probaly my chassi needs another cap kit, or my isolator transformer is kind week, will investigate.

About the "dancing" is more than a pulse on areas with very bright contrast, so when i get the contrast lower it stops "dancing" imediataly, so for sure some issue on chassi or isolator.

About the board has a little doubt, maybe you already see something like, on the scene where the build kind scrools up, it´s not smooth kind jumpy or jerky, i used groovymame with crt_emudriver is extreme smooth, but with original board is not.

Will give a example like Pal and NTSC kind an analogy, one works with 50khz another with 60khz, do you think some sort of thing can happens with an arcade board, it´s like its out of horizontal or vertical frequency, dont exactaly knows how to explain that.

Any clue ?

Other detail, i measure some chips far from the edge conector, and some are 4,38v other 2,81v others 1,89, and most strange thing those yellow caps or resitors all over the boards gives me a solid 5.03v, another mistery !

 

Thanks a lot !

Marcos

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The brightness pulsing is a chassis issue, but it may also be that your chassis isn't matched to the tube, it isnt uncommon to find an eBay yum-cha "universal" chassis installed with an original tube. There really is no such thing as a universal chassis, the ones you buy tend to be set up to flog the tube to death, knowing that the tube is probably old and the seller is unlikely to blame the chassis. Sadly the high quality chassis (that may well have been faulty) went in the bin years ago.

 

Can you upload photos of the chassis?

 

The scrolling could be a board fault, or some more bootleg goodness.

 

I think you are measuring the voltage on the chips wrong, if the decoupling capacitors all read 5.03 your power supply and wiring are fine.

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Hello Womble

For sure will upload some chassi photos so you can see, but it´s a brazilian generic copied from Eygo (old Wey-la) called Eletrocyan.

About the board i´m kind like this new adventure, like i said was used with emulation with groovymame and crt_emudriver that produces a very good result, matching exact same resolution and frequency from the pcb.

But i´m really interest to try fix that board and at least some sprite issue it has, if you could look my album again: https://photos.app.goo.gl/BaAUY9bj4cMSUF758

I uploaded some "China" scene you can see clariry that this board has some issue with sprite, specialy on that bicycle guy that runs on the screen you can see it is very messy with colours change, the software on this board is 920313 (writed in blue colour), there are 2 variants of this on mame World and USA both 920313 both shows the street fighter logo with a "´" , mine doesnt show this, only SF2 logo nothing more, so try to figure out with version is really inside those chips, will dump them after messing with new writes.

So i´m trying to get more information i can get on net and with you guys!

Will buy a eprom programer (cheap ones) just to try to re-write the sf2ce bootleg on those chips maybe it can cure that issue.

But still have to learn more, my board has 5 chips with window (writable ones), already download the sf2ce version, try to check those zip files to see wich one has to be write in wich chip.

Any special advance in write them will me much appreciated.

 

Saw that from those 5 chips:

2 - m27c4001 -15 f1

1 - 27c010a -20 jl

1 - 27c010 -205 dc

1 - 27c512 -15 Fa

 

Already figure out that those numbers after chip is read and write so no big deal if found some faster.

Now i´m searching for a cheap eprom burner !

 

Thanks a lot

Marcos

Edited by m.andrade1
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