Feb 202016
 

I recently received some faulty Capcom pre-CPS PCBs.As most of you know, these board are well known to commit suicide.As you can read from the Dead Battey Society site, “the way suicide work is that the batteries on board supply power to a bit of RAM that holds a decryption table. This table is the key to decrypting the encrypted program stored in the board’s ROMs. When the battery dies, this table goes away and the program code can no longer be decrypted. The CPU no longer has valid code to execute. The board stops working”.

In particular Capcom pre-CPS boards all use a single 3.6V battery and a custom Z80 marked “Kabuki”.The Kabuki has the RAM with the decryption table built right into it.

My Poker Ladies PCB committed suicided and all I got was a static blue screen:

Poker_Ladies_suicided

After reviving it with the use of patched ROMs available from the Dead Battery Society site and doing some modification on PCB (thanks to Corrado for providing me info), the board successfully booted but showed sprites issue:

sprites_issues

EPROMs containing this part of graphics were reafd fine so my first suspicions were on the custom sprites generator marked “86S105” (84 pin PLCC package) which addresses the devices :

86S105_sprite_generator

I played the card of its replacement taking a spare from a shorted Block Block PCB:

86S105_removed

and I won since sprites were fully restored:

sprites_restored

 Posted by at 9:38 pm