Reversing Cadillacs & Dinosaurs Board that has been De-Suicded w/ Decrypted Code

[NoAffinity]

Guys,

I've been asked by a fellow collector to put his C&D, which has been desuicided w/ decrypted code, back to native operation. If I read the instructions for the desuicide/decryption process correctly, some components have been removed which will be needed again. Hoping someone can help, as I'm not finding the info on google.

1) What is the value of C12?
2) What is the value of R33?
3) For the rom that has been decypted, simply repogram with MAME code?
4) What type, value, etc. is the battery that was removed?

All help appreciated. Hoping to get restore another board to native operation.

[leonardoliveira]

I have made decrypted ROMs for all CPS1 QSOUND games which require no modifications to the board for operating. You just need the KABUKI chip to be in the Z80 compatibility mode.

The solution on dead battery society website doubles the EPROM because it doesn't have the decrypted data/code sets merged properly.

The idea of modifying the components near the KABUKI chip are meant to put it on a mode where it operates like a normal Z80 ignoring the encryption function. It involves connecting the /REFRESH pin of the KABUKI (28) to ground. CPS2 boards have a jumper in them which shorts that pin to GND, meant to allow CAPCOM to reuse KABUKI chips as normal Z80s.

You can save yourself the hassle of modding the board simply by lifting the pin 28 so it doesn't connect to the socket and connecting it with pin 29 with a blob of solder.

A properly decrypted ROM will fit on the 128KB EPROM (no need to double the EPROM size) and will work correctly. No extra wires will be required, as well.

[NoAffinity]

The board is already desuicided with the battery removed, and the owner wants it returned to battery operation.

That's all the details I have so far although I asked if things had been removed as the dead battery society outlines, and if the z80 is a kabuki (not replaced) I haven't gotten a response yet. But I'm trying to get a sense for the work involved assuming the DBS method was used.

Nice work pumping out the decrypted sets, btw. You are preserving some great titles for sure.

[leonardoliveira]

I have a decrypted ROM which requires no board modding at all (besides connecting pin 28 of Kabuki to GND).

The battery leaks destroying the board are a good enough reason to not want it battery powered ever again.

Also, the properly decrypted ROMs allow for the use of a regular Z80H chip if the KABUKI ever fails...

[NoAffinity]

I understand, my friend. I agree that's the best way to go, if a board is in a suicided stated. Assuming this C&D in question has been fully modified per the DBS method, and the components have been removed, traces cut, etc. then I have some repair work to do for the owner, to get it back to the point that your decrypted set can be run on the board, no?

So, I still need to know:

1) What is the value of C12?
2) What is the value of R33?
3) 27C010 will do for your decrypted ROM file?

[leonardoliveira]

C12 is a decoupling capacitor for the battery backed power line. For that function it's safe to assume it will be something with a value between 10nf (103) 100nf (104).

R33 value is 1R0 (one ohm). Likely it's there to be used as a jumper. With R33 and C12 removed you can place a Z80H in the socket instead of the Kabuki without any other modifications and the board will work properly.

[NoAffinity]

And, do the cut traces have to be repaired for your rom to work?

[leonardoliveira]

Only one trace is cut, I believe. Pin 30 (Normally connected to 5V along with pins 31 and 32) of the Z80 ROM socket which is meant to release the address line A17 for the ROM to connect with pin /M1 (27) of the Kabuki/Z80 CPU.