Contents[Show]

1. Situation

A HP Elitebook notebook is not booting and just blinks every five seconds or so (keyboard backlightning, buttons, LEDS, screen...).

 

2. Things to try out

A few things to try out. They're variations of trying to make the computer boot with or without the battery etc.

 

2.1. Alternative 1

  1. We will try to start the notebook in BIOS recovery mode.
  2. Make sure the notebook is powered off.
  3. Press and hold the Windows and B buttons, while pressing the power button.
  4. If the computer starts, it should automagically show a BIOS recovery screen. Proceed as instructed on-screen.

 

2.2. Alternative 2

  1. Make sure the notebook is powered off.
  2. Unplug the notebook from the PSU.
  3. Remove the battery.
  4. Press and hold the power button down for twenty seconds.
  5. Try powering on.
    Note! Do not connect the battery or PSU!
    Residual power may remain, so it may actually power on or at least try.
  6. If the computer powers on now, put the battery back and see what happens.

 

2.3. Alternative 3

  1. Make sure the notebook is powered off.
  2. Unplug the notebook from the PSU.
  3. Press and hold the power and mute buttons for about twenty seconds.
  4. Release the buttons.
  5. Connect the PSU.
  6. Press the power button.
  7. If the computer starts - good. If it doesn't, remove the battery and repeat from step 1.

 

2.4. Alternative 4

  1. Try a different PSU, plug it in and let charge for a while. Try powering on now.
  2. Try a different battery, replace it in and let charge for a while. Try powering on now.

 

2.5. Alternatives worth trying or keeping in mind

  1. Keep mobile phones away from the notebook, specifically close to the touchpad. It has been reported that the CPU-shieldning is non-existent. It may mess around with your computer generally speaking.
  2.  ...

 

2.6. Still nothing?

  1. If neither of the above helps, call the HP-support for a possible motherboard replacement. 
  2. No warranty left? Check eBay for used motherboards, or look into buying a new laptop...

 

 

3. Sources

https://h30434.www3.hp.com/t5/Notebook-Hardware-and-Upgrade-Questions/SOLVED-Elitebook-840-g3-not-turning-on-power-wifi-sound/td-p/6784295

https://www.reddit.com/r/techsupport/comments/740gej/hp_elitebook_840_g3_wont_turn_on_no_lights/