So many (broken?) CPS2 A boards - yet another repair thread

[hatmoose]

I bought a massive pile of old CPS2 stuff off a local auction price for the local equivalent of $US300 - the seller was refreshingly honest "Safe to assume everything here is broken is some way". The dude is a fellow arcade fan, chatted for hours.

Anyhoo - now I am the proud(?) owner of a massive pile of "Assume broken" CPS2-A boards in various states of disrepair.

USA with shell
USA with shell
USA bare board
EURO sealed shell
EURO with shell
ASIA sealed shell
ASIA in shell
ASIA in shell
ASIA bare board

Next step is to test them and see if any of them actually work - I think this thread may be about to turn into another CPS2 A board repair thread

 

[hatmoose]

This actually went better than expected


USA with shell = Good
USA with shell = Good
USA bare board = Good
EURO sealed shell = Boots to glitches then solid screen (dead for now)
EURO with shell = Boots to glitches then a solid screen (dead for now)
ASIA sealed shell = Works, sprites do not draw correctly, background and sound fine
ASIA in shell = Works, sprite later flickers in a very interesting way, background and sound fine
ASIA in shell = Works, does not draw some
ASIA bare board = Boots to glitches then a solid screen (dead for now)

So the ones that boot to glitches then a solid screen are probably beyond my ability for now - might come back to those later.

But the ones that have graphical glitches do show some promise

This one has Bad sprites, otherwise fine


Some laters missing/badly drawn, sound dim but OK. In the first pic you can see the word "Alpha" is not being drawn, in the next one some of the detail in the sprites and background is not being drawn


I thought this one had flickering sprites until I took the photo, on the camera screen and in the photo the sprites are crystal clear. Suspect it is not drawing the sprites every frame, maybe every 2/3 frames


Fixing A boards is a massive pain because I can't easily get a logic probe in there - but I'm hopeful that at least some of these are just bad traces

Now that CPS2 has been fully reverse-engineered this should be possible for me. Unfortunately I have absolutely no idea how to read this (yet!)
https://gitlab.com/loic.petit/cps2-reverse/-/tree/master/

 

[hatmoose]

Took me a while to even figure out how the files were laid out.

So the main landing page is here
https://gitlab.com/loic.petit/cps2-reverse/-/tree/master/

There are links to the A board, and the B board, the A board is here and shows a kind of a logical map of how all the bits on the A board join up
https://gitlab.com/loic.petit/cps2-reverse/-/blob/master/93646A/README.md

What that logical map does NOT show is what is connected to what, where. All that stuff is in the downloadable PDF
https://petitl.fr/cps2/93646A.pdf

But it's not in the PDF in a format that im familiar with, so there is some looking up to do

For example, I want to know where pin A3 on CN3 goes.

So first I find CN3 which is on the sheet CN3/CN4 - I look as A3 on CN3 and it tells me that it goes to SOUND-ADR15
But what chip/pin is SOUND-ADR15?
So back to the first page which is the logical map to find SOUND-ADR, it tells me that SOUND-ADR is in the sheet sound_registers
then I find the sheet sound-registers
It tells me that SOUND-ADR15 is on a chip called "UK4" which is a PAL1608, and that Pin A3 on CN3 which carries SOUND-ADR15 is attached to pin 18 of that chip

So TL;DR
Pin A3 on CN3 -> Pin 18 on UK4

So this is kind of cool, but also kind of a pain.
Its a pain because it takes a long time to look things up
But its cool because if I can see the problem (glitchy sprites) I can look for the most logical culprit and start tracing from there, rather than just brute force checking every single trace

In the past there was a spread sheet for the B board that showed what pin was attached to what. Does anyone know if such a thing exists for the A board too?

 

[Blio Seri]

I bought a massive pile of old CPS2 stuff off a local auction price for the local equivalent of $US300 - the seller was refreshingly honest "Safe to assume everything here is broken is some way". The dude is a fellow arcade fan, chatted for hours.

So it was you

I once went to a local repairer and he was in the middle of a massive CPS2 repair plan, with dozens of boards all around his workshop. Epic!

 

[xshezx]

Do you offer any kind of A board repair service? I’ve got 5 that aren’t working (usa and Asia) that I had another member look into a couple and it’s beyond what they can do. Or am I just Better off trying to purchase a few new ones

 

[hatmoose]

Sadly no - I live on a tiny island in the middle of nowhere - getting things in and out takes some doing. For high value "one way" items its not too bad, but wildly uneconomical for repairs :-/