According to the following thread:
The possible culprits for the laptop not turning ON are:
- A defective Mother Board (or Logic Board).
- A charging Port defect.
In my experience, I will add to the previous list:
- The AWM cable run, located below the upper frame (ie. the frame where the trackpad is attached).
Above you can see the original Dell 40cm AWM 20696 E221612-S 80C 30V VW-1 Ribbon cable.
This cable connects the laptop Power Button to the Mother Board.
Detailed in this picture what could happen to your cable.
As you may notice, the golden pins are all ripped off and broken.
If you connect such a cable don’t be surprised if your laptop doesn’t turn ON!
So, before rushing and buying a replacement Main Board for your Dell XPS l501X (but I reckon it also applies to L502X), check your AWM Cable status (ie. take a snap & zoom)!
I got the replacement cable from the following E-Bay shop:
For my wife’s Dell XPS L501X I ordered an AWM 20798 RIBBON CABLE 0.50 mm pitch 12 PIN 400mm 12PIN 40 cm (which slightly differs from the Dell original one, but is 100% COMPATIBLE).
I also got two spare unused Dell L501X mainboards and a spare charging port for sale:
DELL XPS15 L502X MotherBoard nVidia 2G (DAGM6CMB8D0 Rev.D GM6C Black CPU Socket).<- Not Available anymore!
DELL XPS15 L501X MotherBoard (DAGM6BMB8F0 0C9RHD White CPU Socket).<- Not Available anymore!
DELL XPS15 L501X Charging Port.<- Not Available anymore!