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Lenovo ThinkPad L390 CMOS Battery Replacement

Introduction

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

What you need

  1. Lenovo ThinkPad L390 CMOS Battery Replacement, Lower Case: step 1, image 1 of 2 Lenovo ThinkPad L390 CMOS Battery Replacement, Lower Case: step 1, image 2 of 2

    • 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. Lenovo ThinkPad L390 CMOS Battery Replacement: step 2, image 1 of 2 Lenovo ThinkPad L390 CMOS Battery Replacement: step 2, image 2 of 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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  4. Lenovo ThinkPad L390 CMOS Battery Replacement, CMOS Battery: step 3, image 1 of 1

    • Remove the protective tape over the CMOS battery.

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  5. Lenovo ThinkPad L390 CMOS Battery Replacement: step 4, image 1 of 1

    • Pull the white CMOS battery connector directly out of its socket.

    • Lift the battery up and off of the motherboard.

    Edit
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.

One other person completed this guide.

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Luka Eichenwald

Member since: 06/17/25

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

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