Several Capcom CPS1 games manufactured after 1991 and all CPS1 Q sound games have a 3 volt coin type battery backing up data within the CPS graphics chip mounted on the small, top "C" board. When this battery dies it will permanently kill the board. It is recommended to do a "hot swap" with a new battery every few years to insure the continued functioning of the game.

If the battery has already died Tim of ArcadeCollecting.com has developed a modification to revive some of the dead boards by using the "C" board from a Street Fighter PCB. See the The Dead Battery Society page. Tim has also designed a modification  to permanently remove the second 3.6 volt half AA Lithium battery which protects data in the Q Sound Kabuki processor found in CPS1 Q Sound games too.

The procedure to replace the "C" board battery is straightforward but extreme care needs to be taken. If the board loses power at any point it will become inoperative. I've used the following procedure several times to "hot swap" the battery with 100% success but do not hold me liable for any damage caused by following these instructions.

!!!YOU DO THIS AT YOUR OWN RISK!!!

WHAT'S NEEDED:

2 x 2032 3 volt coin type batteries with solder tags,

Soldering Iron & Solder,

Solder Sucker,

2 lengths of wire,

Wire-strippers,

Cross-head Screwdriver (Q Sound only),

Torx Screwdriver (Q Sound only),

Plain Sticky Label,

Multi-Meter,

Earthing Strap,

Safety Goggles.

BATTERY REPLACEMENT PROCEDURE:

1. Solder two wires to one of the 2032 coin batteries, on to the positive (+) tag, the other to the negative (-) tag. This will be your helper battery.

2032 coin type battery

2. Make sure you are wearing an earth strap, remove the small, top "C" board from your CPS1 game, simply by pulling it off.

If working on a Q Sound CPS1 game, it will be necessary to open up the grey plastic case. Remove the four screw covers on the top of the board and unscrew using a cross-head screwdriver. Use a torx bit to remove the three security screws above the JAMMA connector through the green plastic side piece. Pull open the box a little way and unplug the fan connector.

Note: opening this case will break the seals rendering the Capcom Guarantee invalid.

3. Identify the positive and negative solder points for attaching the helper battery. See the pictures below. The procedure is easier on the regular CPS1 "C" boards, more care and good soldering technique is required for the Q Sound "C" board.

Helper battery solder points for CPS1 "C" Board	Helper battery solder points for Q Sound "C" Board

4. Solder the wire from the negative (-) terminal of your helper battery to the negative (-) solder point identified in the photograph.

5. Solder the wire from the positive (+)  terminal of your helper battery to the positive (+) solder point identified in the photograph.

Helper battery attached to a Q Sound "C" board

6. Carefully de-solder the positive (+) terminal of the original board battery using a soldering iron and solder sucker and gently lift out.

7. Carefully de-solder the negative (-)  terminal of the original board battery using a soldering iron and solder sucker and gently remove the old battery. Be very carefully not to short-out or put stress on your helper battery. This is the most dangerous time, remember if the board loses power, even for a split second, the board is killed!!!

8. Take your new second 2032 battery and insert the negative (-) terminal into the "C" board and properly solder the joint.

9. Insert the positive terminal (+) of the new battery into the "C" board and solder the joint.

10. You can now remove the helper battery, carefully de-solder it from the "C" board. Remove the positive (+) wire first, then the negative (-).

11. Insert the "C" board back into the game PCB. Re-assemble the grey plastic box, if a Q Sound game.

12. Put the board back into your cab or test rig and power up. You should now have a fully working CPS1 game with a brand new battery which should last in excess of 3 to 5 years.

13. I suggest you place a sticker on the game board with the date of the battery replacement.