Lenovo ThinkPad L390 CMOS Battery Replacement - iFixit Repair Guide

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Introduction

This guide demonstrates how remove and replace the CMOS battery of a Lenovo ThinkPad L390.

What you need

1. Step 1 Lower Case
  Before you begin, discharge your laptop battery below 25%. A charged lithium-ion battery can catch fire and/or explode if accidentally punctured. Lay the device down with the lower case facing up.
  
  Power off your laptop and disconnect the charger and any peripheries before beginning disassembly.
  
  Unscrew the nine 5 mm Phillips #00 screws that secure the lower case.
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2. Step 2
  Insert an opening tool in the gap between the lower case and the chassis.
  
  Pry around the entire perimeter of the lower case until it fully releases.
  
  Lift the lower case up and off.
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1. Step 3 CMOS Battery
  Remove the protective tape over the CMOS battery.
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2. Step 4
  Pull the white CMOS battery connector directly out of its socket.
  
  Lift the battery up and off of the motherboard.
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Conclusion

To reassemble your device, follow the above steps in reverse order.
Take your e-waste to an R2 or e-Stewards certified recycler.
Repair didn’t go as planned? Try some basic troubleshooting or ask our Answers community for help.

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Luka Eichenwald

Member since: 06/17/25

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Team

Austin Community College, Team 22-2, Watkins Summer 2025 Member of Austin Community College, Team 22-2, Watkins Summer 2025

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