CPS3 Bad Sprite RAM (24000000)

[mmmmaerk]

I just bought a Darksofted CPS3 from a user here and I guess USPS really banged it up during shipping.

This is the first thing I saw when I turned it on. I never loaded a game but after a few power cycles, reseating the BIOS cart, and popping the SD card in and out a few times it eventually ran Third Strike.

I reseated SIMM1 and SIMM2 but I'm still having the same problem.

Sometimes when I turn it on I get a blank black, white or purple screen.

My BIOS cart shell was destroyed right out of the box. From what I can tell the cart itself is still okay.

Did USPS really screw this thing up that badly? It looks like the motherboard is in good shape. It was in a metal case and wrapped in bubble wrap. Is it normal in this hobby for things to just not work when they arrive? I've purchased a Naomi, MiSTercade, and a CPS3 and none of them worked right from day one. I'm not trying to sound like a dick. The sellers always try their best to help me out and I appreciate it. I'm pretty new to all this and I'm wondering if this should be expected.

 

[notsonic]

I would definitely work with the seller to file an insurance claim. It was pretty obviously damaged in shipping.

Could you take up close pictures of the simms and slots as well as the sprite ram?

You can try all the usual clean the simms, slots, check for bent pins, and rearrange them to see if the problem is the stick or slot.

Physically inspect the sprite ram as well for cold joints, corrosion, or even just debris.

I'm not very familiar with troubleshooting CPS3 so all I have is high level suggestions.

 

[mmmmaerk]

Here is a picture I took of the board earlier. Which one is the sprite RAM? I'll take pictures of the SIMMs in a minute. Something tells me this is going to be like my Naomi all over again.

 

[Haydouken]

For context I have no problem sharing that this was my unit. I’m working to make this as right as I can as I’m pretty upset this happened as well. The unit was working flawlessly before and with bubble wrap (albeit in a tight package) on both the metal enclosure and the bios cart—I suspect USPS threw it around like a basketball.

Unfortunately filing an insurance claim is not an option—I did not opt for extra insurance. My bad but they’ve really never messed up this bad or at all before sadly :/. That’s my fault.

That said, we are exploring our options and doing my best to make this right. It is weird because both the bios and the board from the pics does look fine physically but as we all know… this stuff is super finicky and I won’t pretend to be technical enough to figure it out either.

If anyone can help—would be massively appreciated! I am offering to buy a new bios card )if anyone has one) if we do find that to be the issue. I’m really hoping it’s not the simms themselves as I imagine replacing those is not easy. Guess we could explore putting some money into ultra simms haha. But again would love to hear from you all if anyone has any ideas!

Rn asking @mmmmaerk to try rewriting the simms to see if somehow that fixes things. I’m also wondering if, without the cart housing, if the bios card just isn’t connecting well? Again—not knowledgeable enough to determine exactly the issue so any help is welcomed/grateful for!

 

[mmmmaerk]

I tried rewriting Third Strike but it still has the same problem. I know a few guys with CPS3s and maybe I could ask to borrow SIMMs / the BIOS cart just to test and narrow the problem down. I'd understand if they didn't want their perfectly functional CPS3s fucked with, though.

 

[Ape Cosplay]

Is it normal in this hobby for things to just not work when they arrive?

Normal, no. Common yes, for various reasons (one part could have been on its last leg with no warning whatsoever, vibrations during shipping can cause cold solders, humidity and temperature variations can also kill chips, especially air mail in an uncontrolled environment, etc.).

Which one is the sprite RAM?

The one at 1D. Errors on SIMMs 1 & 2 are normal on a DS setup.

 

[thegreathopper]

I would try swapping the Simms around and rewriting another game, I doubt it’s the cart.

 

[tDRG]

I have a spare Superbios cart that you're welcome to borrow if the local connections fall through. Not close enough to help out, but happy to ship it. Like @thegreathopper said, it probably isn't the cart, but it doesn't hurt to try another, and a non-broken shell might make sure it's sitting properly at least.

You can try all the usual clean the simms, slots, check for bent pins, and rearrange them to see if the problem is the stick or slot.

I didn't have these issues, but I had to clean my cart and simms pretty heavily with rubbing alcohol and eventually a pencil eraser before my setup started working. Definitely worth cleaning as well as the usual inspection and rewriting steps.

Is it normal in this hobby for things to just not work when they arrive? I've purchased a Naomi, MiSTercade, and a CPS3 and none of them worked right from day one. I'm not trying to sound like a dick. The sellers always try their best to help me out and I appreciate it. I'm pretty new to all this and I'm wondering if this should be expected.

It happens, fixing stuff up and troubleshooting are great ways to learn. But that sounds like a pretty unlucky streak. Your dead Blast monitor was tough too. Hope it ends up being a simple fix and you're up and running soon.

 

[tDRG]

If anyone can help—would be massively appreciated! I am offering to buy a new bios card )if anyone has one) if we do find that to be the issue. I’m really hoping it’s not the simms themselves as I imagine replacing those is not easy. Guess we could explore putting some money into ultra simms haha. But again would love to hear from you all if anyone has any ideas!

Full or partial sets of original/repro Simms come up for sale pretty often. I saw a set somewhere recently that wasn't too expensive. Easy to drop in and try rewriting. UltraSimms alone don't show up often now though.

 

[Darksoft]

The one at 1D. Errors on SIMMs 1 & 2 are normal on a DS setup.

That's correct. That's related to encryption of the original game.

I would try swapping the Simms around and rewriting another game, I doubt it’s the cart.

That is a good option, rewriting a new game, but actually the test is telling you what is bad.....it's GFX RAM. You need to check those, cold solder or just chip gone south. I also doubt it's the cart.

I have a spare Superbios cart that you're welcome to borrow if the local connections fall through. Not close enough to help out, but happy to ship it. Like @thegreathopper said, it probably isn't the cart, but it doesn't hurt to try another, and a non-broken shell might make sure it's sitting properly at least.

If you can try with a new cart that'd be great, but I think that you are going to see the exact same glitches that you see now.

I didn't have these issues, but I had to clean my cart and simms pretty heavily with rubbing alcohol and eventually a pencil eraser before my setup started working. Definitely worth cleaning as well as the usual inspection and rewriting steps.

In this case, the issue that you probably had was black screen, here, the cart and the system seem to be working well. The problem is rather bad RAM or something related to that RAM, that's been damaged during transportation.

 

[mmmmaerk]

If it's a bad chip, is it replaceable? I might be able to handle fixing a cold solder joint but I don't think I've ever worked on something so small. I'm getting nervous lol.

 

[Haydouken]

Thanks everyone for the support here! It does indeed sound like something wrong with the 1D chip it seems.

Would anyone be game/familiar or skilled enough to help us out if we shipped and paid to fix (though up to @mmmmaerk of course)? I’m also not solder savvy enough to do it unfortunately :/

 

[Ape Cosplay]

Before trying to replace the sprite RAM chip, I forgot to mention it's extremely common for the pins of the GPU/VDP (that big ass QFP304 chip) to come loose. Check that first, especially the pins in the corner closest to the sprite RAM.

 

[ShootTheCore]

Thanks everyone for the support here! It does indeed sound like something wrong with the 1D chip it seems.

Would anyone be game/familiar or skilled enough to help us out if we shipped and paid to fix (though up to @mmmmaerk of course)? I’m also not solder savvy enough to do it unfortunately :/

I can take a look at it if you like. I've had some success with repairing other CPS3 boards: https://shootthecore.tech/arcade-game-pcb-repair-logs/

 

[Haydouken]

Thank you @ShootTheCore! I’ll leave it up to @mmmmaerk to decide but really appreciate you offering your arcane arcade powers here .

 

[mmmmaerk]

I can take a look at it if you like. I've had some success with repairing other CPS3 boards: https://shootthecore.tech/arcade-game-pcb-repair-logs/

Sounds good to me. I appreciate it.

I forgot to mention it's extremely common for the pins of the GPU/VDP (that big ass QFP304 chip) to come loose.

I tried to check this out earlier but I wasn't totally sure which one it was. Would it be obvious if it was loose? I just pushed them all a little bit with my fingers and nothing seemed loose.

 

[ShootTheCore]

Sounds good to me. I appreciate it.

I tried to check this out earlier but I wasn't totally sure which one it was. Would it be obvious if it was loose? I just pushed them all a little bit with my fingers and nothing seemed loose.

The PPU is the large chip near the edge with a black heatsink on top of it (middle-right in your board photo, across from the cart slot). Press down on it firmly with your thumb while switching the board on. If the graphic corruption changes when you apply and remove thumb pressure then the PPU needs to be resoldered. Try the thumb pressure test with each of the RAM chips at D1, D2, D3, D4 and D5 one at a time as well.

Send me a PM if you want me to work on your board and we can hash out the details.

 

[mmmmaerk]

I just tried it and I didn't notice a difference. I didn't want to push too hard but I think I pushed enough. I also just sent you a PM.

 

[streetfighterken]

I've had an original CPS3 for many years and can tell you that simms fail without touching them and cause graphic glitches. I had several fail within a 1 year span for some reason. They've since been replaced with repro simms. I wouldn't doubt that bad simms could produce a false positive on the sprite ram.

 

[ShootTheCore]

Still need to thoroughly test the board before shipping it back, but it seems that the culprit was two legs bent together and touching on a corner of the PPU.

Note that it’s normal for SIMM 1 & 2 to report NG when using the Darksoft BIOS and CD image. The game code is stored on those SIMMs and the code is modified to run without the factory encryption, changing the checksums that the diagnostics expect.