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Do Laptops have a "Power On" signal? Answered

I was thinking of trying a project in which I do a custom watercooling setup on a gaming laptop of some kind. I would like the loop to power on and off with the laptop itself, but I don't want to use USB power or something like. That made me wonder if laptops have a power on signal, like desktop psu's have. Do they have it or something similar to a power on signal?


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4 years ago

If your lapp is old enough to have a 25
pin printer port (LPT) you can find 5V and GND there. A DVI video output
has 5V and GND too.

But why not use the USB? Not as a power
source, but using the 5V as your power on signal? If you tap into an
extension cable, you still can use the port.

Or did I missunderstand and you want to switch the laptop on/off via an external signal? In that case ... no idea. AFAIK, there is no such input. You may open the laptop and tap into the power button. Best to use a relay in that case or do some careful measurements not to fry your laptop. Other than this, you may use Wake-On-Lan.