I have a DELL XPS 12 9Q33. I had it laying on its side resting in between my bed and nightstand, power adapter side up. I had a drink spill onto it from my nightstand and the laptop would not boot/post at all. I found a replacement motherboard and installed it then reinstalled Windows 10. Now the computer runs extremely slow to the point that its not really usable. I had defaulted the BIOS/made changes but nothing helps. Is there another component that should be replaced considering the motherboard is like 80-90% of all of the components? I don't know if the power cable assembly could be damaged or possibly the SSD. Passes the DELL diagnostics tests that can be run from the BIOS with no issues. Any ideas? I really liked this particular model due to its size/weight so it'd be a shame to scrap it.
After the spill, did you make sure to open it up, pull the power and battery, as well as anything attached to it and leave it somewhere safe to dry for days (yes I said days) before even attempting to turn it on?
If not, you likely have liquid still in it. Depending on the type of liquid, it may also have turned into a sticky residue instead of drying which can cause more damage.
If you turned it on without letting it dry correctly (without power/battery/etc.) then you could have damaged any number of parts.