You are a good repairman. I have such a problem. I broke the display on my ASUS G712 laptop before replacing the display the laptop worked but as soon as I turned it off to replace the display the laptop won't turn on anymore. All Mos-fets are checked, supply voltages are OK, BIOS is OK. But there is no reaction to the power button, the laptop also does not show the battery charge on the Led indicator when the charger is connected.