T470 backlight fuse

[Nostos92]

Stupidly tried the change the display on my T470 without removing the internal battery and now the fuse is blown and the back light doesn't power on. I can still see the Thinkpad logo faintly when I power it on though and it works with external displays no problem.

Does anyone know which fuse I should be taking a look at? I figure I should be able to just solder over it.

[rkawakami]

Don't have any specific details on the T470, but traditionally the display fuse has been located next to connector where the ribbon cable from the lid attaches to the motherboard.

[Nostos92]

There is a fuse labelled F39 and a spot for a fuse labelled F44 where the cable from the display connects to the motherboard. The F39 gives me continuity, but the F44 seems completely absent.

[rkawakami]

Knock, knock.... you've got a PM!

[tychon]

I'm in exactly the same spot at the moment. Have a T470 and did the screen replacement without disconnecting internal battery.
The fuse configuration is also the same: the easily accessible side of the board shows fuses F39 (~ 0.5 Ohm) and F44 (absent) close to the video connector.

Was there a conclusion to this?

(Also I'm new on this forum, because it's the only place where I could find the lcd-backlight problem for the T470)

[RealBlackStuff]

You need to look for backlight Fuse F3 (type ERBRD3R00X = 3A/32V/Fast) near the LCD-connector.
Fuses F39 and F44 are 0.5A/32V/Fast and are not for the backlight.

[tychon]

I finally had both the components and the time to attempt a fix. The silkscreen for the board is available in a badcaps.net-thread, which makes it easy to CTRL-F for the fuses.

I managed to remove the motherboard and check the fuses. In my case F3 was okay, but F7 was open/broken, like here. After carefully replacing it with a new fuse (ERBRD3R00X), the backlight works!

This was an exciting adventure, since I never took my laptop apart that far before or soldered components so small.
Thanks for the help!