CS2 MVS using CHA42G-1/2

[Vendest]

I am a bit confused when reading about CHA42G on NeoGeo Dev Wiki.
It seems that the board can only cater for 4x1024 max while installing 4x2048 is possible by mixing first half and second half of each C rom.
I only have CHA42G-1 and CHA42G-2 available.

Can anyone confirm if it's 4MiB or 8MiB?

Thanks

 

[aha2940]

I am a bit confused when reading about CHA42G on NeoGeo Dev Wiki.
It seems that the board can only cater for 4x1024 max while installing 4x2048 is possible by mixing first half and second half of each C rom.
I only have CHA42G-1 and CHA42G-2 available.

Can anyone confirm if it's 4MiB or 8MiB?

Thanks

I guess you can take a look at the boards and determine if all the required data lines are connected, or one is not? AFAIK the 4Mib chips have the same pinout as the 8Mib ones, except the 8Mib has one extra data line. If that line is wired on the board, then the chips can be used. If not, it might be added manually by soldering a cable and getting creative.

Regards.

 

[Vendest]

I guess you can take a look at the boards and determine if all the required data lines are connected, or one is not? AFAIK the 4Mib chips have the same pinout as the 8Mib ones, except the 8Mib has one extra data line. If that line is wired on the board, then the chips can be used. If not, it might be added manually by soldering a cable and getting creative.

Regards.

I've just checked, all lines are connected, thanks
My understanding is that the board is able to handle either 4MB or 8MB of combined C rom. Since the data lines are all connected I would assume it is 8MB.
As for CS2, C1 & C2 rom are 4MB each and since the board does only have 4 C-slots available I think it is necessary to split the C rom into 2MiB each.

 

[Xian Xi]

You need to do a chunk swap for those boards. Use a 42G3 instead, it's the 128 version of the CHA256.

 

[Vendest]

You need to do a chunk swap for those boards. Use a 42G3 instead, it's the 128 version of the CHA256.

Thanks for the advice.
I wish I had the luxury to choose among different boards instead I'm stuck with 42G-1 that I've salvaged from a bootleg.
Chunk swap will be challenging but that's the only road ahead.
I'd like to use M27C160 for C roms. Can you advise if that Eprom is suitable?.

Edit: I have answered to my own question above.

For CHA42G-1 I am about to use
C1 = M27160 (chunk swap)
C2 = M27160 (chunk swap)
C3 = M27160 (chunk swap)
C4 = M27160 (chunk swap)
M1 = AM27C010
S1 = will use MBM27C1000 (still having problem to buffer S1 with topwin....same as Ironclad)

For PROG4096 (vertical slots)
V1 = M27C800 (split)
V2 = M27C800 (split)
Set jumper 6 & 8 as per NeoGeo Dev Wiki

For P1 rom (16MB) can I use the following slots together?
P1 = M27C800
EP1 = 27C4002
EP2 = 27C4002
How should I set the jumpers? Is LS08 required?

Thanks

 

[bustedstr8]

Prog4096

V1-27C160
J6+J8

P1 - 27C160

J2+J3
Remove 4.7K resistor
add LS08

 

[Vendest]

Prog4096

V1-27C160
J6+J8

P1 - 27C160

J2+J3
Remove 4.7K resistor
add LS08

Thanks for the help, it's clear now.
I thought P1 and V1 slot were limited to 8MB each.

Not sure if anybody else encounter with the same issue , whenever TOP3100 (programmer) is connected to my laptop topwin 6/7 will not buffer S1 rom. It does buffer when the programmer is turned off. It's really weird and it has also been doing that when I was making a Ironclad MVS awhile ago.
For Ironclad I found out that S1 rom was corrupted somehow and downloaded another one then it worked.

 

[Vendest]

Got this far today.
Renamed S1 to .bin in order to load into topwin.
Set jumpers J8 J6 J3 J2, removed resistor 4.7k and added 74LS08N
Games boots up and launches the intro fine but the foreground is not displaying properly probably due to bad S1 (same issue I had with Ironclad)
No sound probably due to the fact I did not follow the instruction to burn V1 on 27C160 (I have split V1 and V2 on 2x27C800). I will work on that shortly.
For the rest I believe the chunk swap went well.

 

[bustedstr8]

You can keep the 8Mbit Vroms if you move the two jumpers to the LS139 down one address.

 

[Vendest]

You can keep the 8Mbit Vroms if you move the two jumpers to the LS139 down one address.

So I have set jumpers J5 & J7 for Vroms and it works! Thanks
The bad foreground was not due to a bad Srom but to the cart not sitting well into the daedalus (too loose)
Basically the game works great now!

Thank you for your help bustedstr8 and thank you all

P.S Why does topwin require to change the extension of Srom to .bin everytime before loading remains a bit strange...