HP EliteBook 840 G9 RTC Battery Replacement

Written By: Spencer Day
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HP EliteBook 840 G9 RTC Battery Replacement

Difficulty

Moderate

Steps

12

Time Required

15 - 20 minutes

Introduction

Use this guide to replace the RTC battery (aka CMOS battery or coin clock battery) in your HP EliteBook 840 G9 laptop.

The RTC battery is responsible for powering the system’s clock and retains BIOS settings when the computer is turned off. If your computer loses track of time or resets BIOS settings, the RTC battery may need to be replaced.

When handling batteries, don’t use sharp or metal tools, and don’t bend them or use excessive force. If your battery is swollen, take appropriate precautions.

Still under warranty? Contact HP to learn your warranty status, receive a repair under warranty if eligible, or for further warranty information.

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    • Before starting your repair, allow your laptop's battery to drain below 25%—a charged lithium-ion battery is a potential safety hazard if accidentally damaged.

    • Save your work, fully shut down your laptop, and unplug all cables.

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    • Despite the standards, Phillips screwdrivers can vary in size and shape—two drivers labeled as the same size may fit differently in the same screw. Use the size that fits the most snug into the screw head to avoid stripping it.

    • Use a Phillips screwdriver to fully loosen (not remove) the five captive screws securing the bottom cover.

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    • Position your laptop so the rear edge (with the screen hinge) is closest to you.

    • Insert the flat end of a spudger between the rear edge of the bottom cover and the frame, near the middle screw and ELITEBOOK text.

    • If you're having trouble inserting your spudger, make sure the screw is fully loosened. If necessary, use your fingers to gently pull the screw up.

    • Use your spudger to pry up the cover to release the clip securing it.

    • Leave the spudger inserted under the bottom cover for the next step.

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    • Slide your spudger along the rear edge toward one of the corners to release the rear edge clips.

    • Rotate your spudger around the corner and up the edge to release the clips securing the short edge of the cover.

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    • Reinsert the flat end of a spudger near the ELITEBOOK text.

    • Repeat the previous step for the other side of the cover to release the remaining clips.

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    • Slide the cover towards the screen hinge to disengage the clips on the opposite edge.

    • Lift and remove the cover.

    • The cover should come away easily. If you feel resistance, use the flat end of a spudger to release any remaining clips.

    • During reassembly, slide the clips along the front edge of the cover (opposite the hinge) into their slots on the frame, then lay the cover down. Firmly press around the perimeter of the cover to engage all the clips.

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    • Position your laptop so the front edge (opposite the screen hinges) is closest to you.

    • Use the point of a spudger to push on alternating sides of the battery's sliding connector to walk it completely out of its socket.

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    • Be careful not to bend, crease, deform, poke, or puncture the battery with your tool—a damaged battery is a potential fire hazard.

    • Use a Phillips screwdriver to remove the four 4.6 mm‑long screws securing the battery.

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    • Lift the top edge of that battery and slide the tabs on the bottom edge out of their slots.

    • Remove the battery.

    • Never reuse a deformed or damaged battery—it's a fire hazard. Replace it with a new battery.

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    • Use the point of a spudger to push on alternating sides of the RTC battery's sliding connector to walk it completely out of its socket on the bottom left corner of the motherboard.

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    • While holding up the plastic battery cable clip, pull the cable out from underneath.

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    • Use the flat end of a spudger to gently pry up the RTC battery, separating the adhesive securing it to the frame.

    • Remove the RTC battery.

    • During reassembly:

    • When installing a new RTC battery, make sure the cable is facing its socket on the motherboard.

    • If your replacement battery comes with adhesive pre‑installed, remove the old adhesive from the frame before installing the new battery.

    • If it doesn't, you can reuse the adhesive if it's still sticky. If you need to replace the adhesive, use thin, double‑sided tape to secure your new battery.

Conclusion

Compare your new replacement part to the original part—you may need to transfer remaining components or remove adhesive backings from the new part before you install it.

To reassemble your device, follow these instructions in reverse order.

Take your e-waste to an R2 or e-Stewards certified recycler. Depending on your region, used HP devices and parts can be returned for reuse or recycling through the HP Planet Partners program.

Repair didn’t go as planned? Try some basic troubleshooting, or ask our Answers community for help.

Author

Spencer Day

Member since: 14/09/22

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