Hi tom911
Signed up just to answer here...
Laptops these days hardly use fuses anymore.... If you are lucky they use a 0 resistor in some cases. (SMD type). You generally only get fuses on the LCD/LED connection and the VGA/HDMI connection ports, sometimes the LAN ports as-well. I only find fuses on high end laptops they seem to actually care about the components. Anyways since you mentioned a spill.
I would suggest taking out the motherboard from the case. be patient and avoid build up static, discharge yourself to some tool hooked to earth and use a anti-static mat or a wood board over all avoid touching circuit components but also don't over think it. With the board out make sure there are no build up / corrosion spots on the top side (under the keyboard side). Also you said it was working fine which could mean that the spill weren't that much and only damaged the keyboard since the power button is on the Keyboard. (I hate these...)
So thing is if you can give me your model/detail number on the mother board, its usually printed in white and usually inside a printed block. See image here as sample:
Once I know the motherboard details, I'll look through my bin of schematics and see what the setup is on this one, but i'm pretty sure its the same way Acer did theirs on keyboard power button circuit/signal. With that you can at-least test and see if the laptop comes on without the keyboard plugged in. Other wise depending on the findings on the top side of the motherboard (the side under the keyboard) you will need to check the switches(mosfets) on the input rail 19v(usually depends on make), check for 3.3V & 5V ALW. There are a bunch of things and I'll help you kindly.
### EDIT ###
So I forgot to add that sometimes there are a "debug / test" power switch on the motherboard for instances like these where you want to figure out if its the keyboard or motherboard.... Should be a simple micro switch.
Also working from the Acers that do the same thing, having a power switch as a key on the keyboard. You can follow these schematic cutouts and see what you get on those pins. Be careful not to short two pins with the probe.... Anyways since this is Acer based schematics there is obviously a chance that they won't be the same but in most cases I found them to be exactly the same. I'm adding both the KB Connector pinout and the EC part that receive the Signal from the on/off button.
KB Pinout:
**broken link removed**
You can check the EC pin for as-well for any voltages. Usually in most cases its 3.3V-3.4V And usually its pulled low to initiate a "pressed" signal.
EC Pinout: Pin 114
**broken link removed**
So yeah good luck.