Ketsui - graphical corruption

[NightShadowPT]

Hi everyone!

Just recently got into PGM gaming, but unfortunately, my experience has not been brilliant, with 4 out of 12 games not working properly (+1 motherboard that is not booting).

I will probably open other posts for the other problems as they are different, so I'll start with Ketsui.

I bought a Ketsui cartridge for my PGM, but although it boots and is (arguably) playable I have a lot of graphical corruption on screen. (kindly see the attached photo).

Is there anything I can do to salvage this cart?

And yes, before you ask I have cleaned the contacts in the cart thoroughly.

Any suggestions are welcome.

Thanks.

 

[djsheep]

Have you opened up the cart to see what it looks like inside? Where is the cart from?

 

[NightShadowPT]

I haven't opened the cart, but I guess I can... What should I be looking for?

Got the cart from AliExpress.

Cheers,

 

[djsheep]

Post pics of the front and backs of the two boards in the cart, perhaps there’s something astray someone can pick up on.

 

[NightShadowPT]

To help troubleshoot, and as proposed by djsheep here are pictures (front and back) of both boards...

Curious to hear your thoughts...

Thanks.

Cheers,

 

[Fluffy]

Is all text corrupted? That would be the SMD mounted ROM on board1, or one of the GAL.

 

[NightShadowPT]

Is all text corrupted? That would be the SMD mounted ROM on board1, or one of the GAL.

Most text is corrupted (the text with larger font seems to be displaying ok though).

I apologize, but can you please elaborate a bit more on your diagnosis? (for someone technically inclined (my education is in IT), but an absolute beginner at chips, soldering and boards)

Thanks

 

[stj]

the gold contacts need a good clean with some alcahol
and a higher res picture of board1 front - the smd memory has "interesting" soldering!

 

[NightShadowPT]

the gold contacts need a good clean with some alcahol
and a higher res picture of board1 front - the smd memory has "interesting" soldering!

I've already cleaned them twice... the cotton buds are coming out clean now... But I'll do it once more, for good measure.

Regarding more pictures, here they are.
Please note some may be slightly distorted as I took the picture through a magnifying lens.

Happy to take more, if you feel may be useful.

By the way, thanks everyone for the help.

 

[Fluffy]

Most text is corrupted (the text with larger font seems to be displaying ok though).

I apologize, but can you please elaborate a bit more on your diagnosis? (for someone technically inclined (my education is in IT), but an absolute beginner at chips, soldering and boards)

Thanks

The big EPROM on board1 is program code, the SMD mounted one is the tile graphics (text and background). Board2 provides sprites and sound samples.

I assume the background looks fine? Then I expect the chips are not totally broken and data lines are fine. I'd look for problems on the address lines, both on the ROM and the GAL.

 

[NightShadowPT]

The big EPROM on board1 is program code, the SMD mounted one is the tile graphics (text and background). Board2 provides sprites and sound samples.

I assume the background looks fine? Then I expect the chips are not totally broken and data lines are fine. I'd look for problems on the address lines, both on the ROM and the GAL.

Thanks for the explanation.

Now that you mention it, the background gfx also seem to be corrupted (more photos attached).

Does this mean that the SMD chip is bad? Or is there something I can do to try and remedy it?

I'm disputing the sale on Aliexpress and they have offered me half the money (and I keep the cartridge) or full refund (minus shipping) and I have to return the cart.
I'm trying to assess if this is something I can take as a project and keep the cart, or if it's a lost case and I should return it in full and loose the shipping cost.

I'm quite new to the hobby, but I'm looking to improve my soldering and troubleshooting skills

 

[Fluffy]

Does this mean that the SMD chip is bad? Or is there something I can do to try and remedy it?

Could be, could also be the voltage regulator (does it produce 3.3V?) or one of the GAL. Or it could be a dodgy solder connection.

I'm trying to assess if this is something I can take as a project and keep the cart, or if it's a lost case and I should return it in full and loose the shipping cost.

That is up to you - there are no "unobtainium" chips used, though so far I haven't worked out the equations for the GAL if they need to be replaced. The problem with this and other conversions is that they use 3.3V chips in a 5V environment. That could work fine for ages, or could fail. Many people play with them without problems.

 

[NightShadowPT]

Here's an update for the day:

The Good News:
- I was able to re-flow the solder on the SMD chip mentioned by Fluffy, as well as all other regular solder points (although I did not touch the Surface mounted chips on the second board)
- and the board DID NOT DIE!!! (don't laugh... It's my first try at soldering, so I've very happy I haven't "killed" anything )

The Bad News:
- It did not solve the problem and the graphical corruption remains

Could be, could also be the voltage regulator (does it produce 3.3V?) or one of the GAL. Or it could be a dodgy solder connection.

Happy to measure that with my multimeter, but I'm not sure where to start... would you be able to kindly pinpoint the points I need to measure? (I'm sorry if I'm a bit of a pain, but I really am starting to learn these things)

On a different note, If the problem ends up being the SMD chip, where can I procure one of those? I'm happy to try and switch it myself.

Thanks again for all the help.

 

[Fluffy]

I made a PDF of the cartridge pinout: https://www.arcade-projects.com/threads/pgm-cartridge-pinout.13847/
(Ignore the pin numbers on the PCB. I don't think there is an "official" numbering.)

You can google the chip identifier and find the datasheet: http://www.farnell.com/datasheets/1726422.pdf That way you can identify input and output pins. (Though you can look at where the pads are connected to...)

People have reported success with buyicnow: http://www.buyicnow.com/it.php?i=194 They can program chips as well, that way you don't have to worry about tracking down a compatible programmer or adapter.

You can grab the files from the Mame roms, you're looking for the tiles ROM:
https://github.com/mamedev/mame/blo...0bd0e2d8de3171/src/mame/drivers/pgm.cpp#L4497

It may be worth checking the GAL, as that should be easier and cheaper to replace, though I don't know which one is responsible for tiles on that board. Is one of them getting seriously hot? One of them should be connected to the upper address lines. Testing this properly would require a logic probe or a scope...

 

[NightShadowPT]

I made a PDF of the cartridge pinout: https://www.arcade-projects.com/threads/pgm-cartridge-pinout.13847/
(Ignore the pin numbers on the PCB. I don't think there is an "official" numbering.)

You can google the chip identifier and find the datasheet: http://www.farnell.com/datasheets/1726422.pdf That way you can identify input and output pins. (Though you can look at where the pads are connected to...)

People have reported success with buyicnow: http://www.buyicnow.com/it.php?i=194 They can program chips as well, that way you don't have to worry about tracking down a compatible programmer or adapter.

You can grab the files from the Mame roms, you're looking for the tiles ROM:
https://github.com/mamedev/mame/blo...0bd0e2d8de3171/src/mame/drivers/pgm.cpp#L4497

It may be worth checking the GAL, as that should be easier and cheaper to replace, though I don't know which one is responsible for tiles on that board. Is one of them getting seriously hot? One of them should be connected to the upper address lines. Testing this properly would require a logic probe or a scope...

Thanks a lot for the detailed guide...

I am currently moving between countries, so I'll have to wait a few months to get knee deep into the issue, but this sounds like a nice project to tacke and hone my poor soldering skills (or kill the board once and for all in the process. Either way, I will be learning.

Cheers,

 

[mR_CaESaR]

I've got the exact same carts and fortunately for me I haven't got any graphical issues that you're having.

I've got all 3 of them and they're all the same pcb

Mine is slightly different to yours - my c19 and c20 isn't populated but c39 and c3 is (on both boards).

 

[ShootTheCore]

FWIW, I think you should just return the cart. I think it's very likely that one of the SMD flash chips is bad or was programmed improperly. The PGM mainboard is feeding 5.0V of current into flash chips rated for 3.3V so all bets are off on how long the parts will live. It could damage your PGM mainboard as well.

Fluffy sells blank PCBs that you can use to assemble your own Cave PGM carts using parts rated for the proper 5.0V - there's a thread here:
https://www.arcade-projects.com/threads/pgm-single-game-pcb-assembly-and-troubleshooting.10015/

I also think the assembly process for your own PCBs would be much more interesting for a beginner as well, as opposed to troubleshooting SMD flash chips which requires advanced soldering techniques for removal and reinstallation, as well as SMD flash programmers for reading and writing the flash. I'd highly recommend going the make-your-own route instead of dealing with the poor quality reproductions from AliExpress that don't use the right parts.

 

[jammajunk]

I have the same exact problem than the OP with my Ketsui cart. It worked a few days then the same problems started. I guess the design is just faulty

 

[ShootTheCore]

It's definitely a bad design since they're using SMD flash chips rated for 3.3V when the PGM mainboard supplies 5.0V to them. I'm not surprised at all that they're burning out. They need to add level shifters to shift down the voltage but that would increase the manufacturing cost of the carts...

 

[stj]

maybe someone could sell small adapters to fit between the cart & mobo unless there are 5v chips on the same rail.