Dreamcast CMOS Battery Replacement

Written By: Dark Sakul
  • Comments: 12
Dreamcast CMOS Battery Replacement

Difficulty

Moderate

Steps

9

Time Required

10 - 30 minutes

Introduction

When a Dreamcast ask for time and date every time you power on your system, your CMOS battery is dead. This guide shows how to replace the CMOS battery.

Please note this guide is outdated and I am going to be updating this guide.

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    • Locate and remove all four black 12mm Phillips #02 screws from the underside of the console.

    • Note: Remove the expansion bay to locate the fourth screw

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    • Internal components can be loose. Be careful that they do not fall out when removing the cover.

    • Turn the console right side up.

    • Remove the top cover by gently lifting the upper portion of the console.

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    • Be gentle with the white controller cable as it can be a bit fragile.

    • Disconnect the white controller cable by gently pulling the the cable while wiggling it back and forth until it detaches from the controller board.

    Note that on some Dreamcasts the power board (on the left) overhangs slightly over the controller board, meaning one must also remove the power board at this stage. This is relatively straightforward, fortunately. Remove a screw each at the top left of the power board and at the bottom left of the power board, remove the white clip at the top left, pop out the white clip on the left of the power board and lift the power board out from the front where you have the white block containing eight pins that connect the power board to the sub board. Then proceed per the rest of this guide. Hope this helps.

    JP Asher -

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    • Remove the four 14mm Philips #02 screws located on the controller board.

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    • Disconnect the white fan header from the controller port.

    Perhaps list the battery type an battery holders that allow for easy replacement in the future?

    Brett Kampf -

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    • Remove the controller board by lifting it up from the controller port.

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    • Note where the positive and negative terminals go.

    • Desolder the old CMOS battery from the controller board.

    Hi! If there a way to avoid using a desolder?

    carlosretro -

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    • Solder the replacement battery holder to two electrical wires.

    • Solder the opposite ends of the wires to the controller board. Make sure to match corresponding points on the board with where the previous positive and negative terminals were.

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    • Reinsert the controller board.

    • Attach the battery holder inside with a self adhesive substance, such as double sided foam tape.

    • Insert the battery into the battery holder.

    • Reverse the disassembly directions to reassemble your Dreamcast.

    • Once your Dreamcast is reassembled, go ahead and connect the Dreamcast to your TV or monitor and power, and reset the clock.

Conclusion

To reassemble your device, follow these instructions in reverse order.

Author

Dark Sakul

Member since: 15/05/10

801 Reputation

9 comments

For the step 7, you can get the cmos holder like this from ebay. This holder is perfect fit for the dreamcast controller board and easily replace the cmos battery if it drains out again.

leat -

Just as a heads up, the coin cell that was pictured in this guide (a CR2025 from what I can see) is not rechargeable. The stock battery is an ML2430, so a suitable replacement of about the same size as a CR2025 would be cells with the code ML20XX (ML2020, ML2025, ML2032).

Elanna -

Something that should be noted, even if the pictures kind of hint at it, is that the power board - the large board to the left of the console in Step 3, picture 1 - needs to be removed BEFORE the controller board can be taken out. On my DC the pins that connect the power board to the motherboard have a surprisingly strong grip, so I needed to pull up on that end with some force to get it off. Definitely something to be careful with, as you don't want those pins getting bent out of shape, never mind broken.

HGB -

You can still use something like a CR2025, just wire a diode on the power line. Something like 1N581 or 1N5711 will work.

M. Guy -

Dont use non rechargeble batteries. you can replace it with the little square batteries you found in chinese mp3 headphones… they’re 3.7v, 2000mah and are perfect for the console. This kind of lithium polimer batteries tend to hold charge for as much as six months according to my experience. And they’re easy available, if you can’t find one, just purchase those little chinese micro SD mp3 players/headphones , they’ll have one of this kind inside. Be sure the voltage is 3.7 at a maximum 2.000 mah

toniremords -

Yes I know this guide is out of date as it was very long ago. I am making changes and later updating the pics.

Dark Sakul -

is it not possible to replace the battery without desoldering and replacing the holder? i don’t see why the holder has to be replaced if it’s just the battery that’s bad.

Albert Softie -

It's because the original holder in the dreamcast (from the looks of it based on the pictures) is actually also soldered to the battery itself.

Devilswarchild -

The original Dreamcast backup battery holder is spot welded directly to the battery. And the battery holder is soldered to the Dreamcast mainboard.

Brendan -