A Lenovo ThinkPad X1 Carbon (2nd Generation, the one with the touch-bar in place of the FN keys on the keyboard) we have will power up but will not POST or display any signs of booting an operating system. We had replaced the original Samsung PM851 SSD that was faulty with a new Crucial MX500 M.2 SSD, and it worked for two weeks after that. Here are the facts as we understand them:
-The new SSD is still functional and has been tested in another system
-The issue happened following a restart for a recent Windows update.
-The touch-bar, keyboard backlight, cooling fan, and indicator LED on the SSD all turn on when we try to power the system.
-The system will shut down automatically after a couple minutes if left in the powered state.
-The system does not produce any beep error codes.
-The user has not indicated any liquid damage, and none has been observed internally or externally.
Things we have tried:
-Shutting the system down, and using a paper clip to trigger the hard reset switch on the bottom, as detailed in the service manual.
-Draining power from the motherboard with mains and the battery disconnected for an extended period of time.
-Powering up the system on mains with the battery disconnected, and vice versa.
-Observing the internal display for any LCD activity with a torch to rule out screen backlight issues.
-Connecting an external display via the HDMI port to rule out display issues.
-Powering up the system without the SSD installed in its M.2 slot.
The RAM is soldered and not end-user serviceable, and we do not have any spare parts specific to this model. We would not like to think a Windows update could have caused this, but we can find no reasonable explanation.
We would typically dismiss such a suggestion categorically, but we have had a similar instance of a Windows 10 update causing an issue in the past. Some form of BIOS incompatibility that we've never seen in any other model resulted in a Dell XPS 2710 displaying similar symptoms. The system in question would power up, but no display or splash screen would be observed. A few forum threads full of people reporting the same issue ended up convincing us to ship the motherboard out for a BIOS chip replacement, which ultimately solved the issue. However, besides just not running Windows 10, we never found an explanation for it and Dell never acknowledged it.
Any help or suggestions would be greatly appreciated.