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Tip For Triggering Any Laptop To Switch It “ON”

By on August 31, 2020
laptop turn on how to









Without On/Off switch you can trigger the laptop motherboard to switch it on for troubleshooting. This way you can also confirm that laptop ON/OFF switch is working ok or itself bad.

 On workbench while troubleshooting any laptop motherboard without schematics it is very difficult to trace the ON /OFF triggering switch connection and you have to remove whole On/Off Button Unit from the laptop this is extra and delicate work may damage the plastic lock or “FFC” cable while removing the Unit.

Location of Power Switch:

how to test laptop

Location of Power switch cable socket on Motherboard:

how to test laptop switch

how to fix laptop switch turn on

how to fix laptop can't turn on

Here is the simple trick as follows.

Just find out location of On/Off switch FFC cable Connector on the Motherboard.

Connect the power adaptor on laptop and power it “ON”. Now set the multimeter in voltage range and check and find on which pin of the connector you are getting 3.3V DC i.e. Stand by voltages.(referred by various name I.e. “PS ON”, “NBPSON#”,”PWR BT#” and so on and may vary manufacturer wise).

After confirming the voltage just short that 3.3V (Stand By) pin to nearby grounding point on the motherboard “for a moment”, this will trigger the Laptop to switch “ON” mode.

laptop turn on pin

Or you can trace the signal going from Super I/O or PCH (now a day’s new generation board having PCH chip instead of Super I/O and it embedded all the functions of I/O in this single chip) using Multimeter on Buzzer mode keep one probe on Connector socket (Refer Above Photo) and with other probe touch on every pin of I/O chip one by one multimeter Buzz on particular pin that is trigger pin.

laptop switch to tun on pin

This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.

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Note: You can check his previous repair articles in the link below:




  1. Waleed Rishmawi

    August 31, 2020 at 2:32 pm

    good article thanks for sharing. sometime I get more than one 3.3 volt reading on that panel depending on the model and brand name so the way to know it is by finding the 3.3 volt and press the power button, the 3.3 volts should disappear for a moment and then it comes back and that is how to know when you have more than one 3.3 volts reading. if the 3.3 volts do not disappear for a second check for another 3.3 reading. have a blessed day.

    • Yogesh Panchal

      August 31, 2020 at 6:29 pm

      you are right this is triggering signal from I/O when you press the momentary switch(On/Off) this signal(3.3V) goes low (0V)and accordingly I/O will release the signal to all the stages as per it programmed.

  2. Parasuraman S

    August 31, 2020 at 3:30 pm

    Very valuable tips indeed! Many thanks!

    • Yogesh Panchal

      August 31, 2020 at 6:31 pm

      your welcome! Sir

  3. Albert van Bemmelen

    August 31, 2020 at 5:26 pm

    Good tip Yogesh! Of course when you know where the momentary switch ON switch is you do not need to know the exact pin on the Super I/O chip.

    • Yogesh Panchal

      September 2, 2020 at 3:23 pm

      Thanks! Albert

  4. Tito Kanshulu

    August 31, 2020 at 9:22 pm

    This is an eye opening article Yogesh. It has been alot of work when it comes to testing laptops after repair. One has to do the reconnection. This experience will really add to the knowledge.

    • Yogesh Panchal

      September 2, 2020 at 3:29 pm

      Tito Kanshulu,
      Thanks! for your comment.
      Laptop Assembling and disassembling is very tedious Job. inside Parts are very delicate and can be easily get damage while opening.9

  5. Gerry

    September 1, 2020 at 10:38 pm

    Thanks for sharing and more blessings to come

    • Yogesh Panchal

      September 2, 2020 at 3:30 pm

      Your welcome ! Gerry

  6. Humberto

    September 7, 2020 at 10:38 am

    Good tip, I think this Blog is very instructive and useful.

    • Yogesh Panchal

      September 9, 2020 at 3:01 pm



    September 7, 2020 at 6:51 pm

    ok get more repairs

    • Yogesh Panchal

      September 9, 2020 at 3:02 pm

      Thanks! for the comment.

  8. Mason Sarles

    September 8, 2020 at 8:52 pm

    Great article. Good information. I like this forum I lean from all you.
    Thank you,

  9. Yogesh Panchal

    September 9, 2020 at 3:03 pm

    Mason Sarles,

    Your Welcome!

  10. Paris Azis

    September 12, 2020 at 4:05 pm

    Very valuable tip Yogesh. Thanks for sharing it.

  11. Gihan

    September 15, 2020 at 8:45 pm

    Ancient pc use sand by mode for South Bridge chip

  12. Ang

    October 27, 2020 at 11:30 am

    Yogesh May i know,how to check laptop asus a555l unable power on do u hv ebook step by step to learn and how to make a part rplacement


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