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Remove the CMOS battery

Follow instructions in this section to remove the CMOS battery.

About this task

The following tips describe information that you must consider when removing the CMOS battery.

  • Lenovo has designed this product with your safety in mind. The lithium CMOS battery must be handled correctly to avoid possible danger. If you replace the CMOS battery, you must adhere to local ordinances or regulations for battery disposal.
  • If you replace the original lithium battery with a heavy-metal battery or a battery with heavy-metal components, be aware of the following environmental consideration. Batteries and accumulators that contain heavy metals must not be disposed of with normal domestic waste. They will be taken back free of charge by the manufacturer, distributor, or representative, to be recycled or disposed of in a proper manner.
  • To order replacement batteries, call your support center or business partner. For Lenovo support telephone numbers, see Support Phone List for your region support details.

After you replace the CMOS battery, you must reconfigure the server and reset the system date and time.

When replacing the lithium battery, use only Lenovo specified part number or an equivalent type of battery recommended by the manufacturer. If your system has a module containing a lithium battery, replace it only with the same module type made by the same manufacturer. The battery contains lithium and can explode if not properly used, handled, or disposed of.

Do not:
  • Throw or immerse into water
  • Heat to more than 100°C (212°F)
  • Repair or disassemble

Dispose of the battery as required by local ordinances or regulations.

disconnect all power
The power-control button on the device and the power switch on the power supply do not turn off the electrical current supplied to the device. The device also might have more than one power cord. To remove all electrical current from the device, ensure that all power cords are disconnected from the power source.


  1. Make preparation for the task.
    1. If the server is installed in a rack, slide the server out on its rack slide rails to gain access to the top cover, or remove the server from the rack. See Remove the server from rack.
    2. Remove the top cover. See Remove the top cover.
    3. Remove any parts and disconnect any cables that might impede your access to the CMOS battery.
  2. Locate the CMOS battery. See System-board-assembly connectors.
  3. Remove the CMOS battery.
    • Differentiate between the positive and negative ends of the battery socket as shown below.

    • Failing to remove the CMOS battery properly might damage the socket on the processor board. Any damage to the socket might require replacing the processor board.

    • Do not tilt or push the CMOS battery by using excessive force.

    Figure 1. Removing the CMOS battery
    Removing the CMOS battery
    1. Pry the CMOS battery from the socket with a flat blade screwdriver.
    2. Remove the CMOS battery.

After you finish

  1. Install a new one. See Install the CMOS battery.

  2. Dispose of the CMOS battery as required by local ordinances or regulations.

Demo video

Watch the procedure on YouTube