Street Fighter II bad PAL chip or bad A board graphics processor... or both.

sabrewulf69

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I have this unknown version (maybe Hyper?) of Street Fighter II in my possession. It was given to me because it ran but it had garbled graphics. I assumed it was just a common bad graphics processor, but I swear I had read somewhere long ago that a faulty PAL chip (TIBPAL16L8-15CN) at A1 can also cause this issue. So I swapped it with the other PAL chip on the other side of the B board and the game quit working all together. Could it really just be a bad PAL chip? I'd like some other opinions before I try to track down 2 matching chips for a board with a bad graphics processor.

PALs in original location...
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PALs Swapped...
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Full Board...
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PAL's are programmed parts specific to locations on the board. You can't just take one from one place and put it in another (well... you can, but it will never work).

The photo kind of looks like you might have liquid damage or something near the square custom chip on the top C borad?
 
PAL's are programmed parts specific to locations on the board. You can't just take one from one place and put it in another (well... you can, but it will never work).

The photo kind of looks like you might have liquid damage or something near the square custom chip on the top C borad?
that may be adhesive from the black foam cover that goes around the chip. uncertain why anyone would remove that but whatever

I too made the mistake years ago putting the PAL chips back in the wrong places after I washed the boards. fairly certain I had the same issue. lol if you read close you'll see they have markings that usually tell where they go.
 
PAL's are programmed parts specific to locations on the board. You can't just take one from one place and put it in another (well... you can, but it will never work).

The photo kind of looks like you might have liquid damage or something near the square custom chip on the top C borad?
The stuff that looks like liquid damage is from the sticky residue from the foam. I thought that all that mattered was the code on the PAL chips? Such as both of these are BPAG1. I thought another BPAG1 from the same game would work I didn't know they were deferent other than that, thanks for the info.
 
The stuff that looks like liquid damage is from the sticky residue from the foam. I thought that all that mattered was the code on the PAL chips? Such as both of these are BPAG1. I thought another BPAG1 from the same game would work I didn't know they were deferent other than that, thanks for the info.

I don't know exactly what any of these PALs do but maybe that explains it better. it's probably what makes reading the 27C400 roms possible?
 
That is -most probably- not a case of liquid, PAL, or EPROM (don`t know if you check them already).
Those boards are suffering from custom CAPCOM IC`s failure. If on A board -lower board- the custom IC partially died, then -usually- garbage is the final destination.
If C board -small top- has issues with custom IC, that can be fixed.
Swapping the boards (A&C) with something known working is the fastest way to diagnose.
 

I don't know exactly what any of these PALs do but maybe that explains it better. it's probably what makes reading the 27C400 roms possible?
My limited understanding is each PAL is like a key to the bank of ROMs it is paired with. Obviously you can't move them around the board and you also can't swap in one from another board unless it's the same version as the other.

So in the case of Champ/Hyperfighting, the red PAL is for the graphics ROMs, the Blue is for the Program ROMs, and the Green is for the sound ROMs.

I learned this from experiments from a stack of SF2 boards as well as bits and pieces from here and Arcade-projects.

@loscanones has the simplest way to T/S this, which is to have another A-board at least. If you swap the A board and the graphic issues remains, it's likely the B-21 chip on the C-Board.


1749507156267.png
 
My limited understanding is each PAL is like a key to the bank of ROMs it is paired with. Obviously you can't move them around the board and you also can't swap in one from another board unless it's the same version as the other.

So in the case of Champ/Hyperfighting, the red PAL is for the graphics ROMs, the Blue is for the Program ROMs, and the Green is for the sound ROMs.

I learned this from experiments from a stack of SF2 boards as well as bits and pieces from here and Arcade-projects.

@loscanones has the simplest way to T/S this, which is to have another A-board at least. If you swap the A board and the graphic issues remains, it's likely the B-21 chip on the C-Board.


View attachment 825441
a Final Fight at my old-old job had serious graphic issues one day. I had to resolder the C board chip. I did it with Kester which was a mistake, but I think I ran out of Glowcore. which is way better for surface mount. then the A board crapped out. I still have it for some reason.
 
My limited understanding is each PAL is like a key to the bank of ROMs it is paired with. Obviously you can't move them around the board and you also can't swap in one from another board unless it's the same version as the other.

So in the case of Champ/Hyperfighting, the red PAL is for the graphics ROMs, the Blue is for the Program ROMs, and the Green is for the sound ROMs.

I learned this from experiments from a stack of SF2 boards as well as bits and pieces from here and Arcade-projects.

@loscanones has the simplest way to T/S this, which is to have another A-board at least. If you swap the A board and the graphic issues remains, it's likely the B-21 chip on the C-Board.


View attachment 825441
Thanks for this info, that was very helpful! I dont have any spare CPS1 boards to test with at the moment, but I'll keep it until I come across a good one I can test with.
 
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