iFixit - Answers With Device "HP EliteBook 840 G4"

HP EliteBook 840 G4: Why won't my laptop turn on after pressing the power button

Thu, 27 Jun 2024 21:30:49 -0700

After pressing the power button, it won't turn on and the charging indicator turns on when the laptop is plugged to a power source

⟐ Answered June 27, 2024 at 21:30 MST

HP EliteBook 840 G4: Cooling fan not working properly

Wed, 16 Oct 2024 15:33:43 -0700

It have high sound

⟐ Answered October 16, 2024 at 15:33 MST

HP EliteBook 840 G4: Laptop power issues after battery replaced

Sat, 27 Apr 2024 07:18:40 -0700

I have a Elitebook HP 840 G4 laptop. I replaced the battery as it was stuck at 40% charge and was bulging. After ordering a new battery from IFixIt, I'm experiencing some issues.

I calibrated this battery by charging it to 100%, then depleting it to 0%, then charging it back to 100%

While on battery, I have no issues. I'm able to use the machine just fine. When I plug the machine in to charge, it works until it charges to 100% and it remains plugged in.

Then the computer will randomly shut off.

This only happens while at 100% and plugged in. Eventually, the laptop will shut off with no warning.

Some things I have tried.

Bios and other driver updates

Power profile check to ensure nothing appears odd.

Another round of depletion to 0 and 100 to charge.

Downloaded HP Hardware checker and ran a battery test

Happens on a docking station or its standalone power adaptor.

Tried a different outlet in a different building.

Checked to make sure battery doesn't need reseated in chassis.

Occasionally when going from 0% and charging uninterrupted to 100% - laptop will not power on and charge LED remains on (even if I unplug the power) usually the fix is to hold down the power button for several moments - the charge led will go off, flash 3 times, and eventually let me turn it back on.

I checked voltage on battery at full charge. Shows 13vDC

I really don't want to imagine it being a bad battery. But I'm not sure what other options to go with. Any thoughts?

Thank you both for your advice. The battery connection was seated okay and I tried reinstalling the driver to no avail.

I ended up taking the battery out and replacing it again, but it was used (but newer) battery from a 850 G3 model (same battery - thank God for close generation laptops using similar parts)

I have had no issues with this battery. So I surmise it must have been the new battery after all that was the problem somehow. Which is odd considering the voltage showed okay and the repeated battery tests from HP showed okay.

All in all, this chapter is closed. On to the next mystery.

⟐ Answer accepted April 27, 2024 at 7:18 MST

HP EliteBook 840 G4: My laptop not turning on but when I press the power button it blink

Wed, 30 Jul 2025 22:02:46 -0700

How can I fix my laptop

⟐ Answered July 30, 2025 at 22:02 MST

HP EliteBook 840 G4: laptop not turning on but the fan is running

Mon, 21 Jul 2025 22:06:55 -0700

after turning my laptop on the fan is running for 7/8 seconds but display doesn't show anything and afrer 7/8 seconds it automatically turning off its self.

⟐ Edited July 21, 2025 at 22:06 MST

HP EliteBook 840 G4: How can stop system diagnosis

Thu, 17 Oct 2024 19:31:11 -0700

How can stop system diagnosis

⟐ Answered October 17, 2024 at 19:31 MST

HP EliteBook 840 G4: My battery died fast

Wed, 11 Sep 2024 16:35:06 -0700

my laptop battery died fast and its just charge for 80% and its died also when it close

⟐ Answered September 11, 2024 at 16:35 MST

HP EliteBook 840 G4: Caps lock & mute button light not working.

Wed, 25 Oct 2023 19:28:27 -0700

My laptops caps lock light and mute button light not working.so how can I fix it.please let me know thanks,

⟐ Answered October 25, 2023 at 19:28 MST

HP EliteBook 840 G4: Why my pc show that the internet from ethernet is connected but it doe

Fri, 25 Jul 2025 00:10:46 -0700

Why my pc show that the internet is connected from the ethernet but don't work

⟐ Answered July 25, 2025 at 0:10 MST

HP EliteBook 840 G4: Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz 2.71 GHz, 16.0 GB (15.9 GB

Thu, 02 Apr 2026 17:58:15 -0700

Dear IFIXIT

reference mentioned subject, my computer run very slow ?

Any APP to test the system?

⟐ Answered April 02, 2026 at 17:58 MST

HP EliteBook 840 G4: My Internal Keyboard is clicking on its own.

Mon, 23 Jun 2025 01:59:59 -0700

My Internal Keyboard is clicking on its own. What should I do?

⟐ Answered June 23, 2025 at 1:59 MST

HP EliteBook 840 G4: "My laptop isn't charging anymore, but t

Sun, 08 Mar 2026 12:51:28 -0700

"My laptop isn't charging anymore, but the charger is fine. When I plug the charger into the laptop, the green light on the adapter keeps blinking."

⟐ Answered March 08, 2026 at 12:51 MST

HP EliteBook 840 G4: keyboard key stop working

Wed, 05 Nov 2025 06:07:08 -0700

my keyboard keys stop working one by one

⟐ Answered November 05, 2025 at 6:07 MST

HP EliteBook 840 G4: When my laptop goes into sleep mode, the screen stays black

Mon, 20 Oct 2025 07:30:53 -0700

When my laptop goes into sleep mode, the screen stays black and I have to restart it. What should I do? Other than that, the laptop works perfectly, so I don’t understand what could be causing it. My power saving mode is set to activate at 20%.

⟐ Answered October 20, 2025 at 7:30 MST

HP EliteBook 840 G4: Laptop hanging frequently ands stops working

Thu, 20 Mar 2025 23:28:07 -0700

My laptop hangs minutes after i switch it on. Tried changing the ram and hard disk but has the same problem. What could be the problem?

⟐ Answered March 20, 2025 at 23:28 MST

HP EliteBook 840 G4: Why is my pc touch pad not working

Thu, 13 Mar 2025 07:13:54 -0700

Why is my pc touch pad not working

⟐ Answered March 13, 2025 at 7:13 MST

HP EliteBook 840 G4: I didn't turn it on

Wed, 01 Jan 2025 09:35:25 -0700

When I put the charger in it gives a signal but when I try to turn it on it doesn't turn on help me please

⟐ Answered January 01, 2025 at 9:35 MST

HP EliteBook 840 G4: Why is my audio device not working

Wed, 06 Nov 2024 04:53:48 -0700

sound device not working

⟐ Answer edited November 06, 2024 at 4:53 MST

HP EliteBook 840 G4: Keyboard key automatic pressing c

Thu, 06 Jun 2024 14:49:41 -0700

Me laptop's keyboard's 'c' key in automatically pressing without pressing it with a notification sound

⟐ Answered June 06, 2024 at 14:49 MST

HP EliteBook 840 G4: Laptop power not ON on battery

Sat, 25 May 2024 09:54:39 -0700

I bought it second hand laptop 3 month works good but suddenly laptop not power ON on battery but its does on Power Adopter and showing battery recharging. When i unplugged power supply its goes OFF. Please help.

⟐ Answer edited May 25, 2024 at 9:54 MST