DARKSOFT CPS III Bios and CD Releases

[hatmoose]

I did it myself with the following gear
Hot air station (Atten)
Temp controlled soldering station (ksger t12)
SMD tip for the station (bc2 clone)
Some decent solder and flux gel
EPROM burner with NOR adapter (t48 w/ADP1)
binocular microscope
With the right gear it’s very possible, but I didn’t find it easy.

 

[xodaraP]

Hot air station to remove, bevel edge or knife tip soldering iron and decent (not from Aliexpress) flux and solder to attach

Drag solder to attach all pins then repeat to ensure good contact and remove bridges. Add more flux each time you remove and reapply soldering iron

The biggest thing is to take your time. Especially when clearing the bridges if you try to rush it it will just get worse

 

[hatmoose]

Replace 29f400 on PCB with programmed 29f800 (48 pin).
Raise pin 16 and proceed as in the attached diagram.

Thank you very much for sharing this, I would love to replicate your work!

Unfortunately I'm not very experienced with flash/eprom and tend to ask lots of silly questions - your patience is appreciated



Description says lift pin 16 (A1
Diagram shows pin 18 (A7) being attached to switch and ground
Not sure if there is an error in the diagram, or if im an idiot. or both

So do I lift pin 16 and attach that to the switch/ground? or do I leave 16 alone and lift 18 and attach that to switch/ground? or do I lift 16 AND also attach 18 to switch/ground?

Edit - whoops, after I read the instructions I understood, leaving this here in case others have the same question

Diagram shows A(ddress)18 being lifted and tied to switch/ground.
A18 is physically on pin 16 in the chip package


So exactly as per the instructions, raise pin 16 and attach it per the diagram

 

[tovar]

Hi Hatmoose,

The 29f800 memory is twice the capacity of the 29f400 (this is a no-brainer).

As it has double capacity, within the 29f800 there are 2 different programs: a 29f400 with the "CD" program and another 29f400 with the "NO CD" program.

The highest address "A18, pin 16" decides which half you use depending on whether it is tied to positive (via the resistor) or tied to ground (via the switch).

To avoid that there is originally some type of connection that interferes with pin 16 on the printed circuit, I recommend lifting- isolating pin 16 of the 27f800 and proceeding according to the diagram.

If you have any questions about this, I will be happy to answer them.

 

[hatmoose]

since I have a few of these to do I'm imagining some kind of helper board to keep everything tidy and make it more reversible (in so far as desoldering and desoldering TSOP is a fun day at the reversible beach

the vacant spot where the battery came off seems like the logical place, its close to the board edge, has GND and +5 easily available. The goal would be to have the slide switch right on the edge of the board, so the actuator could poke up through a hole in the cart.


So maybe something like this? I still need to measure the hole spacing and etc.


I'm still really struggling to understand the difference between the "theory" and "practise" diagrams
Theory: Switch between +5v and GND on A18 to switch between BIOS "banks" makes perfect sense

Practise: as drawn in the schematics (and recreated here?) has me me stumped, I'm not doubting that it does work, but my self-taught electronics cant see HOW it works.

 

[Fluffy]

https://eepower.com/resistor-guide/resistor-applications/pull-up-resistor-pull-down-resistor/

Your schematic is basically the first diagram in the article.

 

[tovar]

That's how I do it

 

[mR_CaESaR]

This is amazing.

I'd be all for some sort of pcb helper to be able to switch between cd and no cd.

Even if it's a jumper of some sort that you have to take the case off to reduce having to hack up the plastic - probably someone will do a 3d case eventually.

 

[hatmoose]

I'm about 50% sure all the holes will line up I checked the hole pattern with all the carts I had access to (A, B, D)
have not checked C or Darksoft cause I dont have them. The +5V hole on the top edge is a bit fiddly, needs to be about .4mm pin


Here's how it looks. Will produce some prototypes and report back. Gerbers attached if anyone else is silly enough to try my untested work.

The switch (MSK12C01) is very tiny, its a standard part for PCBA at JLC and by default only protrudes 1mm - there is more than 1mm of clearance inside the shell, so the switch is entirely concealed inside the shell.

It would be possible to cut a hole in the shell to reach the switch, and possible to print a shell with a hole, and possible to use a MSK12C01 with a longer handle, all of which would give access to the switch from outside the shell.

And now we wait approx 2 weeks for delivery. Fun!

 

[djsheep]

Game changer! Nice work as always @hatmoose

 

[kazuo]

If that ends up working out I'm building one for sure. Would save me a lot of headache when I am fiddling around between CD & NO CD setups.

Great work!

 

[kikaso]

Hi, there

I'm having trouble booting Warzard / Red Earth. After writing to SIMMs and choosing the region, I just get a black screen. In order to get the game to boot, I have to boot from the Darksoft menu, (hold 1P start after rebooting) and choose 3. GAME BOOT and it's the Japanese region that boots. The game seems to run fine otherwise. I'm running the latest UltraBIOS on a custom SH2 and the CD image with the Makoto fix. I also tried the image with no Darksoft text for competition but got the same results.

Anyone know what's going on here? I tried searching the forum but couldn't find another example of this.

 

[Darksoft]

Hi, there

I'm having trouble booting Warzard / Red Earth. After writing to SIMMs and choosing the region, I just get a black screen. In order to get the game to boot, I have to boot from the Darksoft menu, (hold 1P start after rebooting) and choose 3. GAME BOOT and it's the Japanese region that boots. The game seems to run fine otherwise. I'm running the latest UltraBIOS on a custom SH2 and the CD image with the Makoto fix. I also tried the image with no Darksoft text for competition but got the same results.

Anyone know what's going on here? I tried searching the forum but couldn't find another example of this.

this looks like the typical error when you have the wrong CD image, like i.e. custom SH2 vs Standard SH2.

 

[kikaso]

It's an original cart so that's custom SH2, yeah? I'll try a standard SH2 image in case parts were swapped at some point?

Thanks for the reply!

 

[Darksoft]

maybe post a picture of your cartridge so we can see the chip please.

 

[kikaso]

Same results with the standard SH2 image. 4th Strike won’t load with the new CD image either

 

[xodaraP]

You can’t run 4th Strike on custom SH2 which is what you have there. You need to replace the CPU with a non encrypted SH2

Have you installed a standard BIOS on a custom CPU perhaps?

 

[mR_CaESaR]

Yeah i've made that mistake the first few times when I first did the mod.

I burnt a "standard" bios, in a custom cart and then wrote a standard cd on the flash.

I eventually got it by reburning a custom bios with the custom cd and rewrote the game.

 

[kikaso]

Good idea, @xodaraP and @mR_CaESaR

I didn’t burn the BIOS but can re-burn to rule that out.

 

[mR_CaESaR]

Good luck!