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xodaraP

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KotR should be a 12mhz Dash board and will have the correct battery powered C board (KotR is my donor)

If it has a 10Mhz A board it’s still fine as long as it’s a short board, the crystal can be changed out
 

raffy92

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I've noticed a lot of posts with confusion surrounding the different CPS1 A-Board differences. This confused me for a while as well when I was researching which boards to look for/buy. So I decided to piece together a guide.

CPS1 "Long" Board (10MHz)
Good for playing 10MHz games, also the largest PCB variant
cps_long.jpg
A-Board alone: https://i.imgur.com/EDviXRh.jpg
note that the audio chip is visible on the bottom left, is upright, and has a large heat sync, the volume knob is above the audio amp and the dip switches are perpendicular to the JAMMA edge.


CPS1 "Short" Board (10MHz)
Good for playing 10MHz games, also the smallest PCB variant
cps_short.jpg
A-Board alone: https://i.imgur.com/GTFN9Vr.jpg
note that the PCB is so short that you can't even see the audio chip under the B-Board, the audio amp is laid flat to fit under the B-board, the volume knob is moved to the left edge of the board so that it is still accessible and all of the dip switches are parallel with the JAMMA edge.


CPS1 "Dash" Board (12MHz)
Good for 12MHz games (some 10MHz games will run fast). this is the ideal candidate for a CPS1 multi
cps_dash.JPG
A-Board alone: https://i.imgur.com/4e6k3q7.jpg
Dimensionally and layout-wise this is nearly identical to the "short" board. the easiest way to tell if it's a "Dash" board is to look for the "CPS-Dash" sticker behind the dip switches. outside of the sticker the only way to tell the difference is to look for the crystal and see if it's labeled as 12MHz or 10MHz. 12MHz games, as seen here, tend to have shorter b-boards exposing more of the A-Board below.



CPS1.5 "Q-Sound" Board (12MHz + Q-Sound)
only good for CPS1.5 games
cps_qsound.jpg
A-Board alone: https://i.imgur.com/8SD9L5K.jpg/
Q-Sound Board alone: https://i.imgur.com/SWDANNg.jpg
All of these games come in a black plastic case with a filter-board (in this picture you can see the lower half of the case and the filter-board), also note that there is an additional Q-SOUND PCB in the stack between the A and B boards which has audio chips is on the top left rather than the bottom left. The A board is similar to the CPS-Dash board but does not have the audio section populated.


Upgrading a 10MHz PCB to 12MHz
According to Apocalypse even if you do have a 10MHz board it can be upgraded to a 12MHz by replacing the crystal: Interest Check: Darksoft CPS1 Multi - Unofficial
Most games should work on either board, there will just be more slow-downs on the 10MHz variants.
This image shows where this crystal is located.


Here are the different games and which board they're compatible with:
10MHz (can only use 10MHz board)
1941: Counter Attack
Captain Commando
Carrier Air Wing/U.S. Navy
Dynasty Wars/Tenchi wo Kurau (12MHz version also available)
Final Fight
Forgotten Worlds/Lost World
Ganbare! Marine Kun
Ghouls'n Ghosts/Daimakaimura (12MHz version also available)
The King of Dragons
Knights of the Round
Magic Sword: Heroic Fantasy
Mega Twins/Chiki Chiki Boys
Mercs/Senjou no Ookami II
Nemo
Pokonyan! Balloon
Street Fighter II: The World Warrior
Strider/Strider Hiryu (12MHz version also available)
Three Wonders
U.N. Squadron/Area 88 (12MHz version also available)
Willow


12MHz (can only use "Dash" board)
Adventure Quiz Capcom World 2
Area 88 (10MHz version also available)
Daimakaimura (10MHz version also available)
Mega Man: The Power Battle/Rockman: The Power Battle
Pang! 3
Pnickies
Quiz & Dragons: Capcom Quiz Game
Quiz Tonosama no Yabou 2: Zenkoku-ban
Street Fighter II': Champion Edition
Street Fighter II': Hyper Fighting
Street Fighter Zero
Strider Hiryu (10MHz version also available)
Tenchi wo Kurau (10MHz version also available)
Varth: Operation Thunderstorm


Q-Sound (can only use "Q-Sound" board)
Cadillacs and Dinosaurs
Muscle Bomber Duo
The Punisher
Saturday Night Slam Masters/Muscle Bomber: The Body Explosion
Warriors of Fate/Tenchi wo Kurau II: Sekiheki no Tatakai/Sangokushi II




I'm still very much a CPS noob so please correct any inaccuracies I may have posted, but hopefully these pictures and descriptions will help people seek out and buy the right PCBs for their CPS projects.

I did nt check yet on my version yet but on the upper post, Kotr was classified in the 10 Mhz category. Also on eBay there is currently a Kotr with the A board unplugged and it is actually a 10 Mhz. If possible I prefer to not modify my version which is an original one, sell it and found a game which can give me the Cps dash and the appropriate C board.
 

mthngn

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Hi,

I bought this C-board:
Capture d’écran 2022-03-31 à 17.30.09.png



I removed the wire/bridge between ppu and D3.

IMG_6793.jpg


IMG_6792.jpg


Is that all?
no battery, no reprogrammed anything.

Regards.
 

duffcon

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Hi,

I bought this C-board:

I removed the wire/bridge between ppu and D3.

Is that all?
no battery, no reprogrammed anything.

See here:
https://www.arcade-projects.com/thr...e-for-the-cps1-multi.13106/page-7#post-299448


Yes But not much.

The Old C-Board De-Suicide Method:
CPS-B-21 Pins 45 and 46 are normally connected to ground. The old "de-suicide" method was to disconnect these pins from ground (on some chips this was done with a trace cut, on others they lifted pins where there were traces under the chip). After disconnecting from ground these pins were then tied to +5V.

Undoing the modification:
To reverse the mod you simply need to disconnect these pins from +5V and then re-connect them to Ground.
  1. Start by removing the bodge wire
  2. If the pins are lifted then solder them back down in place.
  3. Use a Multi-Meter to check and make sure there is no lingering continuity between the pins and +5V
  4. Connect Pins 45 and 46 to ground. If the pins were lifted then you might already be done. On some boards this might be just adding a solder jumper to the nearest ground pin, on other boards you might need to add a new bodge wire to tie the pins to ground to "fix" any cut traces.
  5. Do a final check to make sure there is no continuity between +5V and Ground

Testing That you were successful:
If you have a CPS1 C-Board Infinity Key you can easily set the jumpers to whatever game you're trying to run, then plop that on there, and if it boots/plays you've confirm functionality.

Alternatively you can re-install a battery and then use the Arcade Hacker's Key Restore method to reprogram the original keys. and if that boots/plays you've confirmed functionality.
View: https://www.youtube.com/watch?v=w19r6jgTja8


Obviously once you've got the multi in-hand you can also use the multi to confirm that it's done right, however I would recommend waiting until you've got the Multi setup and running on modified C-Board first, so that you know the A-Board and multi are functioning properly before you undo the modification, that way you aren't trying to trouble shoot multiple things at a time.
 

mthngn

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thanks @duffcon

after checking: pins 45/46 (near ppu B21) seem to be not connected to the GND (41 43 47... yes)
So i am going to wire them to GND: can you confirm?

I don't undertand why pin 45 (near ppu B21) seems not be connected tu CNA/45: how can you explain that? the same thing for pin 46.

Regards


Edit: I think understand why...


IMG_6795.jpg
 
Last edited:

duffcon

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So yes, they were once connected to ground. Most of the time they just cut the traces. You can sand off some of the solder mask and bridge to ground again, or use a bodge wire and just connect it to ground wherever.
 

9999 Damage

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Amazing resource. Thank you, @twistedsymphony !

I bought a King of Dragons DASH board that appears to have a 92641C-1 C-board. I don't see a battery on the back of it, so it might be de-suicided. Before I can check for the telltale signs that twistedsymphony enumerated, I have to remove the C-board to see the other side. Do I just pull, or do I need to do something to unlock it? It didn't budge with a light pull and I don't want to pull too hard if it turns out I'm supposed to push in on a clip somewhere or something.
 

the Goat

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I have to remove the C-board to see the other side. Do I just pull, or do I need to do something to unlock it? It didn't budge with a light pull and I don't want to pull too hard if it turns out I'm supposed to push in on a clip somewhere or something.
It is purely held on with friction of the many pins. Pull up on each side individually just enough to move it a millimetre or two. Then it should come loose no problem.
 

MudGuts83

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Just ordered the multi. Pulled out the c board from its now dust covered box. It appears that the component at CCX3 has broken off.

I don't know what these parts are called. But based on the photos its probably the same part located on CCX1 and CCX2?
 

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the Goat

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Just ordered the multi. Pulled out the c board from its now dust covered box. It appears that the component at CCX3 has broken off.

I don't know what these parts are called. But based on the photos its probably the same part located on CCX1 and CCX2?
Looks like a tantalum capacitor.
 

Kujako

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OK... so got my multi-kit in today, have a clean CPS1-Dash "A" board ready, but looking at my "C" boards I'm confused. I have two modified ones, but the one I'd planned on using has a modification I've not seen before. It has a battery, where as the other (yellow dot) does not.
IMG_1191.jpg

Looking at the one on the left under the scope...
Quick Camera Image 2022-05-27 at 7.32.37 PM.png

I see pins 41 through 44 bridged. Then there's a bodge wire running to pin 60 (also ground?)

The other (yellow dot) lacks a battery, but has the more "traditional" bodge wire.
Quick Camera Image 2022-05-27 at 7.33.23 PM.png


If I'm understanding everything, the end goal is to have pins 45 & 46 grounded and to have a battery. Is that about it? Anyone know if having pins 42 & 44 also grounded is an issue? I guess if I were thinking this through I would replace the battery any how...
 

Darksoft

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Those C Boards dont look like they had a good job done on them. You might be shortcutting some signals without even noticing it.

to know which pins go where, check here: https://github.com/ArcadeHacker/ArcadeHacker_CPS1

Pin 42 in the B21 should go to pin 19 Dark Green in picture above
Pin 44 in the B21 should go to pin 20 Light blue in picture above
Pin 45 and 46 should be connected to GND.

PLEASE NOTE: the mod described above and information from ArcadeHacker have
worked and been accurate for us, your case may differ and you are doing any mods or
reversals completely at your own risk. We take absolutely no responsibility when not using
original and untouched C Boards. PROCEED WITH CAUTION AT YOUR OWN DISCRETION!

1653723301696.png
 

Dloop

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Those C Boards dont look like they had a good job done on them. You might be shortcutting some signals without even noticing it.

to know which pins go where, check here: https://github.com/ArcadeHacker/ArcadeHacker_CPS1

Pin 42 in the B21 should go to pin 19 Dark Green in picture above
Pin 44 in the B21 should go to pin 20 Light blue in picture above
Pin 45 and 46 should be connected to GND.

PLEASE NOTE: the mod described above and information from ArcadeHacker have
worked and been accurate for us, your case may differ and you are doing any mods or
reversals completely at your own risk. We take absolutely no responsibility when not using
original and untouched C Boards. PROCEED WITH CAUTION AT YOUR OWN DISCRETION!

1653723301696.png
Is this for rewriting the c board or what is this?
 
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