Things You'll Need
Instructions
Turn the Sega Dreamcast off and unplug it from the power source.
Remove the modem from the side of the Dreamcast. A small latch beneath the modem can be slid to disengage the component.
Turn the console over and remove the four screws from its base using a Phillips screwdriver.
Turn the console slowly back over and then lift up the top case, which is now loose. This reveals the components inside the Dreamcast.
Remove the power board so that you gain easier access to the rest of the components. The power board is the bronze colored circuit board at the front left of the exposed Dreamcast. This board has a number of tall cylindrical components attached to it and a connector at its rear. Gently pull the board from this connector.
Remove the two screws holding the power board in place. There is one at the rear of the board and one at the front. Remove each with a Phillips screwdriver.
Pull the plastic clip out that is also holding the board in place. This clip is gray and located at the front left of the board.
Lift up and remove the power board, grabbing it only by the edges.
Ensure no debris or collections of dust are in the Sega Dreamcast now that you have the system open. Carefully clean any such debris out with a soft, dry cloth, but refrain from rubbing down any components directly.
Locate the battery. This can be seen behind the removed power board. It appears as an upright, vertically oriented silver object that is circular in shape. It is partially encased by a light blue, rubber-looking border, making the battery distinctive and easy to spot. This is the rechargeable CR2032 battery. Visible damage does not have to be on the battery to warrant replacement. If the Dreamcast cannot remember its internal date and time settings, the battery simply has to be replaced.
Remove the screw from the base of the battery, which connects the spherical top to the board beneath it. Lift out the battery for replacement.
Insert a new rechargeable CR2032 battery in its place, securing it in place with the screw.
Replace the power board by following its removal steps in reverse, then replace the top cover of the Sega Dreamcast. Your battery is fixed.