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Hi have acquired a laptop to repair and it has shown some signs of life with a solid white light and reading the battery voltage and the voltage coming into the board it seems fine but will not power on. Have noticed the power button is shorted to ground even not when pushed.
cheers
here you go … I can check other things for voltage too .. just let me know .. cheers
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Hi @capsitup ,
Have you checked that the power button is not actually short circuit? Pin 2 of the power button is always connected to earth. When operated the button connects the earth through on pins 1 & 3 to the IO chipset.
Here’s the LENOVO YOGA 510 14IKB COMPAL BIUS4S5 CIUY0Y1 LA E221P REV 1.0 schematic that may help. (verify that the model number matches your motherboard’s model number)
Go to p.32 to view the Power button for Yoga circuit. It connects the earth to pin 114 of the motherboard I/O chip (southbridge) - see p.34.
Hopefully a start.
这个答案有帮助吗？
Hi mate I’ll have to see cause it is open at the moment and when pressed still open and your a a legend for the schematics .. I’ll check tonight
When you said "Have noticed the power button is shorted to ground even not when pushed", I took this to mean that there was an earth on both the input and output side of the switch regardless of whether it was manually operated or not. That's why I suggested you check if it was short circuit.
Thanks jayeff .. Yes I probe the two points on the switch and get a short (like the switch is Normally closed not normally open till pressed) download the file and will have a look at that page you said .. it’s also interesting that I get voltage to the USB ports too.
Don't get caught because it may be that there is an earth coming from the chip or somewhere else
It pays to keep in mind that the switch is still connected to the board and there may be an earth coming from somewhere else so that it appears that there is short circuit switch contacts i.e. a short circuit through the earth - normally earth is on pin 2 and there is another earth on pin 1 & 3 coming from somewhere else when it shouldn't be there, if you get my drift ;-).
You may have to isolate the switch from the board to prove whether the problem is in the switch or not. Looking at the schematic it seems as though the switch is hard wired via the motherboard tracks directly to the I/O chip and not via a easily removable connection i.e. flex cable etc so unsoldering it may be the only option so that you can test it
Hi jayeff .. okay so your saying look else where .. it’s interesting because im getting voltage in to board and to the USB port and the LED power on button (it’s not glowing btw even though it reads 3v) I’ll add some photos for you
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Get voltage from the main board and from the Led next to the power button
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