CPS3 Problem board

[KnuckleheadFlow]

I got a Third Strike board for a good price (by today's standards). Listed as "untested", I hoped that it was just a dead cart. Well after finally sorting out flashing the super bios (bad 29F400 apparenty), I soldered it back onto the cart and I still have a black screen. More of a very dark grey I guess. It doesn't exactly look the same as with the stock bios, so I don't think I wiped a good cart. The voltage on the never-changed battery was 2.8v. Where as before it was a full screen of black, now it looks squished, as if it was letterboxed.

Anyway, the cart is clean, the soldering on the 29F400 was good (I'll have another look at it tomorrow just to be safe). I just cleaned out the SIMM slots, though I don't think that'd be the problem. I also cleaned out the cart slot with rubbing alcohol and a cotton ball, waiting for it to dry now. I thought it might be the mod wires coming up from the underside, since one of them was shorting to the pin next to it, but that didn't change it either.

So... any tips on what to check next?

 

[Mitsurugi-w]

I always clean the cart contacts with Brasso. Dirty carts are a huge problem with CPS3.

 

[KnuckleheadFlow]

Haha, man, guess what I used? The gold was reflecting all across the ceiling when I was done.

 

[kuze]

The cart also has to sit just right or you'll get a black screen. It's worth reseating a few times and if that doesn't work, test a known good cart on the mobo.

 

[KOarcade]

I would for sure double check your voltage levels. I have always had problems with cps3 not booting correctly when there was a shortage on the 12v.

 

[KnuckleheadFlow]

Ah now there's something I can check! "Thou shalt check voltages," how could I forget? Thanks. Could it be that the NAC's PSU is going and it can't handle the extra draw of the CD-ROM?

I don't have another CPS3 cart to test with and I don't know anyone that does. In fact, other than a buddy with a big red MVS, I don't know anybody else interested in arcade hardware. Except when it's time to play it, of course!

I kinda wish I had a schematic for this. When I got the board, there was some kind of tarry residue that had dripped onto the RAM chips. I can't shake the suspicion it might be weed tar from a pipe. The CDROM smelled like it too. How desperate you gotta be to use your arcade cab as a bong?! It took a lot of swabbing with acetone to even put a dent in it. I got most of it out, but I think there's still some underneath a chip or two. I can't clean it out and who knows what it's done to those j-leads. Heck, even my cleaning might've pushed a lead loose. It's probably not the cause of my problems but I had a Nomad that wouldn't power on, opened it up to find someone tried the old coca cola conformal coating technique around the DC jack. Cleaned that up and it turned on just fine.

If it's not the 12V, it might be finally time to learn how to use that logic analyzer I got.

 

[KOarcade]

You would be very surprised about the voltage levels. I sold a perfectly good CPS3 recently to someone here on the forum and I even mentioned that the board was being very picky with power levels. I even made sure I streamed using the setup before it sold. Good thing because when the buyer got it. He wasn't able to power it on. It just gave him a "black screen". Finally after he purchased a good supergun with a descend PSU. The board just power up and worked.

Cleaning, power levels, and carefulness. Three words to go by with the ways of the cade boards.

 

[cpsystem3]

I would for sure double check your voltage levels. I have always had problems with cps3 not booting correctly when there was a shortage on the 12v.

12v is only used for audio amplification and the CD-Roms motor. Circuit board logic levels on arcade pcbs are either 5v or 3.3v. Lack of, or low 12v will not cause the CPS3 to fail to boot.

I would recommend inspecting your board carefully in direct sunlight. There are potentially gouged traces on the solder side of the PCB, or lifted pins on the surface mounted IC's.

For what its worth, I've repaired countless PCB's over the years, none of them being CPS-3. Its to the point I won't even attempt a motherboard repair, they're just too complicated with the custom architectre. I personally will only repair the cartridges. In my (vast) experience with the system, once the motherboard is dead its dead.