Tip For Triggering Any Laptop To Switch It “ON”
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:
Location of Power switch cable socket on Motherboard:
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.
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.
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:
https://jestineyong.com/logitech-mouse-pointer-freezes-on-the-monitor-screen-intermittently/
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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
Waleed,
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.
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
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
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
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
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
Thanks!
Humberto
LUGUYESIA
September 7, 2020 at 6:51 pm
ok get more repairs
Yogesh Panchal
September 9, 2020 at 3:02 pm
LUGUYESIA,
Thanks! for the comment.
Mason Sarles
September 8, 2020 at 8:52 pm
Great article. Good information. I like this forum I lean from all you.
Thank you,
Mason
Dallas,TX
USA
Yogesh Panchal
September 9, 2020 at 3:03 pm
Mason Sarles,
Your Welcome!
Paris Azis
September 12, 2020 at 4:05 pm
Very valuable tip Yogesh. Thanks for sharing it.
Gihan
September 15, 2020 at 8:45 pm
Ancient pc use sand by mode for South Bridge chip
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