T495s only outputs to external display

[razorball]

I got hold of a Thinkpad T495S with Ryzen 7 Pro 3700U and 16.0 GB RAM. I don't know the history behind this, but, I'm running into a weird issue where I cannot get the display to work on the laptop. The machine outputs fine through HDMI to an external monitor. Within Windows, I only see a single display output device (my monitor), while the laptops display is not visible.

For diagnosis, I tried the following,

• Cleared CMOS by unplugging battery & CMOS and draining out the machine by holding power for 30 seconds. No difference.

• Tried the hard reset button under the lower shell. No difference

• Tried booting without the wifi card incase it was interfering. No difference.

• Updated to the latest bios and ran the Lenovo Self Update tool. No difference.

The weird thing is that the display is likely not the issue as during boot I can see a really faint Lenovo logo (like the startup one) before it disappears and the screen goes black. I initially assumed it might be a backlight issue with a blown fuse, but I ran the LCD function test by holding Fn + Left Ctrl + power which iterated through all of the colors. I'm at a loss for what could be wrong. Any help would be greatly appreciated.

[RealBlackStuff]

Welcome to the Forum.
The "really faint Lenovo logo" means that you have blown the backlight fuse F3, near the LCD-connector.
It is 3A/32V/Fast, type ERBRD3R00X.
Nearby is also another fuse F7, same value, that you should also check.
Unfortunately I don't have a boardview, so the fuse(s) could be on the opposite side of the motherboard.
To make life easier, you can solder the new one on top of the old one.
Make sure to disconnect the main battery before you begin.

PS: if it helps, T495s has the same motherboard as the X395.
How to take it apart: https://www.ifixit.com/Guide/Lenovo+Thi ... ent/149166