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April 10, 2008

Replacing Your Motherboard CMOS Battery

Computers contains a battery to keep time when the computer is off, much like a watch or some alarm clocks. Just like a watch, the battery needs to be replaced when it runs low on power. You can purchase these batteries in most department or PC specialty shops. For most of us, the computer becomes obsolete long before we need to change the battery, but new technology allows us to keep our systems longer and longer by swapping out components.
How and Where to begin when changing the CMOS battery:

CMOS is an abbreviation for Complementary Metal Oxide Semiconductor. You may need to change your CMOS battery if your computer clock isn't accurate when you boot. However, if your pc loses time as the computer runs, that's another problem.

It is important to get into the BIOS settings and write down any special settings. If you remove and replace the battery quick enough, you might not lose your settings, but it's best to write everything down.

Remove the side panel so you have access to the motherboard. You should have the pc unplugged and be wearing an antistatic wrist strap to avoid damaging your boards.

1. Jot down notes if you cannot access the battery directly and need to remove cables. Note the connection and orientation of each cable. Do not unplug anything from the board unless absolutely necessary.

2. The battery is often only held in place by a couple of thin clamps that can be gently slid aside or raised enough to get the battery out. DO NOT BREAK THE CLAMPS.

3. Once the replacement is in, replace any cables, close the case and boot the computer. Go back into the BIOS and restore any settings, if necessary.

Discharge the CMOS

It is sometimes necessary to discharge the CMOS. This is done by a set of jumpers on the motherboard, often near the CMOS battery. The small plastic clip is normally on pins 1 and 2. To discharge the CMOS memory, make sure the power is off and move the jumper to pins 2 and 3. You can return the jumper to pins 1-2 after only a few seconds. Now the CMOS memory has been cleared.

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