Reverse engineering 161 in 1 cartridge to change Rom games

[leonk]

Maybe they mean just the M1 rom.

M1 is used to test the z80. Bad z80 won't trigger the memory error, only way to test that is with the DIAG ROM.

FWIW, 240p test suite does MROM test on itself during boot up. If you got a bad MROM on the cart, it will tell you. It has audio tests afterwards to validate the z80.

 

[MaRC]

I need help.
I successfully flashed my own cartridges, but then a friend asked me to flash his. I flashed two C roms, but the third one wouldn't pass the test. I re-soldered it onto the board several times, but now not only the last chip but also none of the previously successfully flashed chips are passing the test. The P roms are also failing the test. I tried to run a Line Capacitance test on a programmer that doesn't have any jumper boards connected, and it seems to have two stuck data lines on the C2/C3 pins. Is there anything I can do about it, or should I replace the STM32?

 

[leonk]

I had a chance to try a CPU swap on AES and can confirm that the Toshiba CPU is 100% compatible with multicarts. I don't know why this is the case, but here's my guess.

- The 68000 is made by Motorola. It's what you find in all MVS PCBs
- To reduce size, for the AES, SNK decided to use the SDIP package CPU (1.778mm pitch pins vs 2.54mm) They had no choice but to go with 2nd source (Hitachi or Toshiba) as Motorola doesn't make SDIP 68000 CPUs
- The Toshiba timing seems to be much closer to Motorola than Hitachi. Is it caused by flash memory that's too fast? Who knows. I've seen glitches with original carts on Hitachi CPUs where the same cart on a Toshiba CPU AES doesn't have them.

Here's what I used:

- CPU: (https://www.aliexpress.com/item/1005010298730761.html) Get the MC68HC000P10. It's a 10Mhz part but it runs at 12Mhz clock speed of the system. $3
- Socket: (https://www.ebay.com/itm/285532545623) 64 pin, 1.778mm pitch, 21.54mm wide (the last part is important!) $2

The most difficult part is removing the old CPU. I used my Hakko FR-300 with 0.8mm nozzle set at 400C.

 

[XtraSmiley]

Awesome work @leonk!

I'm still surprised no one is making these from the factory yet. I see repro carts out there, how hard is it to just do a proper multi cart?

 

[xodaraP]

Awesome work @leonk!

I'm still surprised no one is making these from the factory yet. I see repro carts out there, how hard is it to just do a proper multi cart?

They can keep selling cartridges the same way they always have (and have increased the price significantly since this mod became known). All risk is on the buyer doing the mod and if they break it, they may buy another one further increasing profit

Or

They can spend money on changes to the PCB design, additional parts, new programming for the ROMs and reduce their profit margin as a result

Option 1 has no increased costs, has seen a recent big increase in profit and there’s no additional risk - no benefit to option 2 for the sellers

 

[leonk]

They can keep selling cartridges the same way they always have (and have increased the price significantly since this mod became known). All risk is on the buyer doing the mod and if they break it, they may buy another one further increasing profit

Or

They can spend money on changes to the PCB design, additional parts, new programming for the ROMs and reduce their profit margin as a result

Option 1 has no increased costs, has seen a recent big increase in profit and there’s no additional risk - no benefit to option 2 for the sellers

100%!!!

The carts they sell now are V2 carts, an older 2019 design vs the 2022 V3 design. They reverted back because of price. Best Price has always been the driving force for most of the sellers on AE. Making a better cart will cost significantly more and they don't want anything to do with that. If they can save $0.01 by removing 5 capacitors they will and they have.

 

[Neo-Alec]

If the Aliexpress seller prominently displayed whatever number of hundreds of games are on the Vortex cart, I think there would be buyers willing to pay more for access to more games. The Aliexpress site does make it kind of difficult to comparison shop though.

 

[Niko]

I dont know if I fully agree that the sellers reverted back to the V2.

If I had to guess, they're probably still sitting on a stock pile of older version multicarts they're wanting to clear out before they consider doing another production run or producing a new version.

If that was truly the case, we'd have never seen the "CBOX" with the nice AES style shell. They'd just have kept selling them with the cheap acrylic cases.

 

[leonk]

I dont know if I fully agree that the sellers reverted back to the V2.

If I had to guess, they're probably still sitting on a stock pile of older version multicarts they're wanting to clear out before they consider doing another production run or producing a new version.

If that was truly the case, we'd have never seen the "CBOX" with the nice AES style shell. They'd just have kept selling them with the cheap acrylic cases.

I know this for a fact. I've been buying these carts from my supplier since 2023. At this point, I've purchased over 300 of these carts and have seen every single revision made in the last decade in person.

The latest carts sold are V2 carts with a 2019 (c) date on them. V3 carts have a 2022 (c) date on them (silkscreen on the PCB). The only difference is the current V2 vs old V2 from 2019 is the shell. They used to be banana yellow, now they're black. At this point I can tell you what month your V2 was made by looking at the SROM/MROM maker and chip size.

I've had a couple of times when the cart came to me with a missing component, and the factory sent it to me in my next order. They are making them all the time using the older PCB design.

 

[Niko]

Have you tried reaching out to the supplier about doing a custom run with all the games?

8 ~ 10yrs ago I had a lead on a supplier who mentioned they could do it but would have required a sizable deposit.

 

[leonk]

Have you tried reaching out to the supplier about doing a custom run with all the games?

8 ~ 10yrs ago I had a lead on a supplier who mentioned they could do it but would have required a sizable deposit.

They won't do it because it will mean designing a whole new PCB. The Vortex carts I make today are V2 carts with new custom PCBs to expand the existing flash memory. It is too time consuming to produce and populate using the existing 2019 boards. Their goal is to hit a price point for all the markets they serve. The cost increate to make a Vortex will push many of their customers out and they would rather do the same old, same old. It's a volume business afterall.

 

[fraggle200]

If the Aliexpress seller prominently displayed whatever number of hundreds of games are on the Vortex cart, I think there would be buyers willing to pay more for access to more games. The Aliexpress site does make it kind of difficult to comparison shop though.

i think it's twofold. they don't want to spend the cash making a new board, sourcing new chips etc as it all costs money
BUT if they did do it I wouldn't surprised if everyone who's ever bought a 161 cart would also buy their full set cart.

they just don't see the investment as worthwhile just now as they're making bank off the carts they have as it is.

 

[Old baby]

i think it's twofold. they don't want to spend the cash making a new board, sourcing new chips etc as it all costs money
BUT if they did do it I wouldn't surprised if everyone who's ever bought a 161 cart would also buy their full set cart.

they just don't see the investment as worthwhile just now as they're making bank off the carts they have as it is.

It's not that I'm unwilling to make new PCBs.
The original retail price of the blue 161v3 was around $40, at least that's what I could buy them for back then.
The profit was just marginal, hardly any real money to be made.
The mold cost for the casing alone was huge.
It was the distributors who made the real profit, not me.

Remaking them requires professionals to invest a huge amount of time,
and they're not willing to put in more investment.
I keep asking when they'll produce more,
and they just say they won't make any without large bulk orders.

As for the black transparent 161v2,
it seems to be a downgraded version compared to the blue one.

If someone develops a perfect finished product and there are orders,
they won't refuse to produce them.

 

[MaRC]

Please remind me - it is advisable to power the cartridge board from the neo geo, and the vcc and gnd pins of the usb blaster need to be soldered to the board, or only the 4 data pins?

 

[leonk]

Please remind me - it is advisable to power the cartridge board from the neo geo, and the vcc and gnd pins of the usb blaster need to be soldered to the board, or only the 4 data pins?

USB Blaster can't power the PCB, you need an external Vcc source.

 

[MaRC]

USB Blaster can't power the PCB, you need an external Vcc source.

I'm powering the cartridge from the neo geo itself, but do I need to solder the Vcc and Gnd contacts of the blaster to the jtag, or only the tck, tdo, tdi, and tms contacts?

 

[leonk]

Think of electronics flowing like water, they always need a return path to source, else you have a broken circuit. Vcc has it's own GND from the Neo Geo itself. But the other pins on the programmer don't have a return path, so you must solder ground for them. Only Vcc doesn't get soldered.

 

[pluger]

hi i use this way to program the clpd. The resistances: 4.7k Ohms 5%

 

[Butter Meister]

hi i use this way to program the clpd. The resistances: 4.7k Ohms 5%

I faintly remember in Quartus II it may be possible to program the flash chips via JTAG. It may take forever, but its gotta be easier than desoldering and programming that way. It's worth looking into again.

 

[HornheaDD]

Useless reply:

I remember when this was unveiled and I was hopeful that it was doable by the end user and it wasn't, and I think no one wanted to do it until rewrite and Leon offered.

Just a cool thing to see how all of this progressed from a post made in 2020. Now we've got Vortex carts out the wazoo (sadly at a higher cost, but what can you do), and someone is working on a PGM Multi.

What a time.

Thanks to all the people that made it happen.