The CMOS battery, located on the left here, allows storage of essential settings on a computer's motherboard.
Like all personal computers, the Dell CPx laptop series comes with a motherboard, or CMOS, battery that allows the motherboard to store essential settings when the laptop's main battery is empty and the power cord disconnected. A low CMOS battery can cause a constellation of unusual PC behaviors, such as randomly turning on and off, and error messages stating the system does not match configuration. When these problems start to occur, it's time to change the CMOS battery. In the Dell CPx series, the battery is tucked into a foam-padded pocket under the palm rest.
Instructions
Preparing to Open Laptop
1. Shut down the laptop and close the lid.
2. Remove the power cord from the back of the computer and the battery from underneath.
3. Drain any remaining power in the computer by holding down the power button for 30 seconds.
4. Wrap an anti-static bracelet around your wrist, and attach the end to a grounded metal object, such as a metal chair leg.
Opening Laptop
5. Close the display and turn the computer over. Locate seven screws marked "K" and remove them with the Phillips screwdriver. Turn the computer upright and open the display.
6. Insert the flat-head screwdriver under the blank key to the right of the space-bar row and pry up the key. Flip the keyboard to the left and pull the flat wire bundle connecting the keyboard to the motherboard.
7. Close the display again and turn the computer 180 degrees so the back of the computer is facing you. Locate three screws marked "D" and remove them with the Phillips screwdriver.
8. Turn the computer back 180 degrees and open the display. Pull the flat wire bundle connecting display and motherboard. Pull the display straight up and put it aside.
9. Flip the computer over again and locate five screws marked "P." Pull up the palm rest and disconnect the flat wire bundle directly above the trackpad. Place the palm rest to the side.
Changing CMOS Battery
10. Remove two screws from the trackpad bracket, a silvery metal casing about the size of a credit card.
11. Pull the bracket away from the palm rest, taking care not to damage the wires connecting the trackpad to the palm rest.
12. Remove the CMOS battery wire from the bracket. Pull battery and foam from the wire assembly.
13. Connect the replacement battery to the wire assembly and set it into the palm-rest bracket. Turn the bracket over and replace it in the palm rest.
14. Follow the instructions in reverse to reassemble the palm rest, display and keyboard.
Tags: palm rest, CMOS battery, flat wire, flat wire bundle, screws marked, wire bundle