SF2' (CPS') Issues

PCB problems and fixes
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cowise
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SF2' (CPS') Issues

Post by cowise »

I just picked up an SF2' board set for cheap but it's presenting issues when plugged into my Neo 29.

My current setup is:

SF2' Board ---> Jamma PCB/MVS Cab converter (from JammaBoards) ---> MVS connector

Currently the game starts up fine but the backgrounds and some graphics are missing. Part of the title screen graphics are fine, and the character sprites in-battle show up fine, but almost everything else is black. I'm guessing this might be an issue with one of the ROM chips not being seated correctly, so I am in the process of reseating them. The other issue that has me stumped, though, is that it looks like button 4 is constantly being pressed. After I insert a coin, the game immediately picks the default character and when the battle starts that character constantly does a light kick. To diagnose the issue I've tried:

- Removing the Kick Harness
- Unplugging the connectors to all of the cab buttons

But the "kicking" issue still remains.

Has anyone seem anything like this before? When the buttons are all hooked up, the joystick works as do the other punch buttons (I can input a special move and it'll play through and temporarily override the constant kicking), so I don't think it is a problem with the converter.
LAW666
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Re: SF2' (CPS') Issues

Post by LAW666 »

Does the character still kick with the kick harness unplugged?

I had the same issue with my Wrestlefest board, but the player (one and two) would just kick once at the start of a fight and the button would no longer work as the switch was still pressed.

It turned out to be a couple of faulty 245 IC chips which I replaced with new socketed ones and now it works fine

http://www.jammaplus.co.uk/forum/forum_ ... sue-solved

Is this an issue for just player one or is player 2 affected too?

Hope this helps.
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cowise
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Re: SF2' (CPS') Issues

Post by cowise »

LAW666 wrote:Does the character still kick with the kick harness unplugged?

I had the same issue with my Wrestlefest board, but the player (one and two) would just kick once at the start of a fight and the button would no longer work as the switch was still pressed.

It turned out to be a couple of faulty 245 IC chips which I replaced with new socketed ones and now it works fine

http://www.jammaplus.co.uk/forum/forum_ ... sue-solved

Is this an issue for just player one or is player 2 affected too?

Hope this helps.
Thanks for the response!

The character still kicks with the kick harness unplugged. They also still kick even if I unplug the leads to all of the play buttons on the cab (ABCD). Both player 1 and player 2 are effected by the issue, as well.

Thanks for the link--I'll take a look and see if this might be my issue, as well. If anyone else has any input, I'm open to suggestions!
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Re: SF2' (CPS') Issues

Post by Asure »

As CPS1 consist of three separate boards, it is easier to diagnose if you have another boardset to swap stuff around with.

But alas, the most likely candidate for this issue is the top (small) board also known as 'C board' which holds the kick inputs, a few PAL devices and a big B21 chip, which acts as a sort of graphics multiplexing video card thing.

If the B21 card is broken, it will cause the exact issue with missing fore/background layers, or wrong priorities.

Button #4 input is on the C board as well.

You can borrow another C board from a CPS1 board, as long as the chip matches (B21) it should work. Narrow down the fault first.
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Re: SF2' (CPS') Issues

Post by cowise »

Asure wrote:As CPS1 consist of three separate boards, it is easier to diagnose if you have another boardset to swap stuff around with.

But alas, the most likely candidate for this issue is the top (small) board also known as 'C board' which holds the kick inputs, a few PAL devices and a big B21 chip, which acts as a sort of graphics multiplexing video card thing.

If the B21 card is broken, it will cause the exact issue with missing fore/background layers, or wrong priorities.

Button #4 input is on the C board as well.

You can borrow another C board from a CPS1 board, as long as the chip matches (B21) it should work. Narrow down the fault first.
Damn, that sounds like a pretty good diagnosis of the problems I'm seeing. I don't have any other C boards (B21 or otherwise). Looks like I'll have to pick one up to be sure. :awe:
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