Replacing the battery of your motherboard (CMOS battery)

Topics

Symptoms

If your computer is showing the following symptoms:

Error with date and time options.

You are prompted with the following error messages:

bios cmos checksum error defaults loaded  
bios cmos battery low cmos wrong memory size  
no operating system 
CPU overclocking failed 
New CPU has been installed and more.. 

These problems may be due to the fact that your CSMOS battery is depleted and itâ€(TM)s about time to replace it.

Replacement sequence

It is recommended that you change the CSMOS battery every 5 years.

Saving the BIOS data

Open all the BIOS screen and note all the information on a piece of paper. It's important that you don't make any modifications. Once completed this document will be useful to check out if all the parameters are correctly inserted after replacing the battery.

Identify the CMOS battery

The CMOS battery is some kind of round shape button, thin in diameter, sometimes it can be hidden by extension cards or connectors or on old PC it has a cylindrical shape.
The battery model most widely used is the CR2032:

• Where :
  • CR- lithium battery
  • 20 - 20mm diameter
  • 32- Thickness 32* 0.1 mm
• This type or battery is easily found and has an average price of 4 to 5 Euros

How to locate it:

• Turn off your PC
• Remove the power cable attached to your System unit and remove the hatch.
• Discharge your System Unit from static electricity by touching it with a metallic object.

Removing the discharged battery

• First of all be sure that your System unit is laid down horizontally.
• The +ve pole of the battery should be visible.
• Remove the battery, but avoid any forcing and any contact with other parts of your motherboard (refer to the manual provide with your motherboard).
• Go to your local retailer any buy a battery of the same model or something equivalent.

Installing the new battery

Be sure that the battery is place correctly (firmly) in the slot allocated (positive side visible, depending on the model of your motherboard).

Verify the BIOS data and resetting the clock

• Once the operation complete, it is important to configure the BIOS settings.
• Start your PC.
• Enter the BIOS.
• Modify the Date.
• Verify if the parameters are the same as the one noted in step 1(perform any modifications needed)
• Save and quit BIOS.