CPS2 – CAPCOM – Suicide Battery Replacement

A friend of mine, Daniele, gave me this board from his personal collection for a quick check-up and maintenance. As all we know CAPCOM uses on these CP SYSTEM II (CPS2) boards an anti-piracy measure protecting the game. The game code is encrypted and it’s decrypted on-the-fly by the main CPU using a special decryption key stored on a battery powered RAM. So if the battery is running out of power the decryption key is lost and the board “dies” preventing the CPU running the correct program code and obviusly the board stops working. This is why the battery who powers the special RAM is better known as “Suicide Battery”. So before the board commits its “programmed” suicide, the battery should be replaced.

Like Mr.Ozzi (a friend of mine) said, speaking about his personal arcade boards collection: “a suicide battery is like a cucumber in the a*s, the more batteries, the more cucumbers you have!“.

Here is the CPS2 board, a Japanese SUPER STREET FIGHTER 2X :

The CPS2 system is a two parts sandwich, a bottom mainboard with a black case and a top game board with a coloured case, which holds the game EPROMS and the SUICIDE BATTERY too. This game board is made in green plastic because is a japanese CPS2 but you can find them in different colours for each different region :

Region Case Version Screen
Japan Green plastic White text
U.S.A. Blue plastic Red text
Euro/Etc./World Blue plastic Blue text
Asia Grey plastic Yellow text
Hispanic Orange plastic Green text
Brazil Orange plastic Magenta text
Oceania Blue plastic Orange text
Rental (any of above) Yellow plastic (Any of above)
(Any of above) Black metal “all-in-one” (Any of above)

This table is taken from CPS2 page on Wikipedia.

Once opened the game ROM board we can see its PCB and the battery, the red one on the bottom right side, on the following picture:

Measuring the battery reveals it’s not in so good condition to power the security RAM anymore, it’s around 3.48 Volts. It’s enough to keep the game working but a new one should be around 3.6V and this is a clear signal that the battery which served this board for over 10 years il slowly depleting its power. So we must replace it, here is the new battery ready to be soldered on the PCB:

We must proceed to remove the old one desoldering its leads on the pads in the back side of the PCB:

Now there will be the “hardest” part, once removed the old battery the special RAM will remain with no power and we must hurry replacing the battery, because the battery-powered RAM will loose its contents in minutes. Some guys says 10 minutes, other guys says over 1 hour, by the way i don’t want to discover it for sure …

So if you are going to replace it tremendously really slowly you must use a helper battery for the process, but if you are a PRO there should be enough time to take a shot too … LOL !

Once removed the old battery, the new one can be soldered in its place, but be careful to install it in the proper way, the positive (+) side of the battery must go on the left side, the negative (-) side instead goes close to the edge of the PCB, like the photo below:

Solder the battery on the underside of the PCB, cut the exceding length of the leads off and make ABSOLUTELY sure that the battery is soldered properly and in the right way.

Job done … now we must test the board …

Yeah! Repeat the test and power up the board again after few hour to make sure the new battery is doing it’s job …

… if the board has committed suicide is a clear sign that something has gone wrong, but thanks to the effors of Eduardo Cruz, Artemio Urbina and Ian Court few months ago they announced the successful reverse engineering of CPS2 security protection, allowing to DE-SUICIDE and restoration of any dead games without hardware modifications.

Here is the links to their site … follow them, it’s a very interesting reading:

Eduardo Cruz (30 April 2016). Arcade Hacker: Important Capcom CPS2 Announcement.

Eduardo Cruz (13 September 2016). Capcom CPS2 Security Programming Guide.

… another case closed!

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