Question HP ZBook Studio G3 LCD backlight not working

[eccyearner]

Hi,

The LCD backlight on my HP ZBook Studio G3 isn't working. Using a flashlight I can see that the display is working so it's not totally dead.

I'm guessing it's either a blown backlight fuse, or a broken backlight.

Does anyone know where the fuse is for the display backlight? I looked at the "HP ZBook G3 Backlight Fuse Location" and disassembled my laptop, but the only fuse I can find seems to not be blown, testing it with my multimeter a few nights ago showed about 2-3 Ohms. I'm not sure I'm testing the correct fuse, though.

Linked images show both sides of the motherboard. The fuse I've found and tested is the one labeled "F2", indicated by the big red arrow.

Imgur link
Imgur link

If that's the correct fuse then I guess the backlight is broken. If that's the case, does anyone here have any tips or pointers to where I can purchase a new one, and how to replace it?

Thanks,

 

[helpstar]

is the video ribbon cable still connected correctly? unplug and replug on the motherboard and the display and check display light again

View: https://youtu.be/52Ux-m-A0O8?t=401

 

[eccyearner]

is the video ribbon cable still connected correctly? unplug and replug on the motherboard and the display and check display light again

View: https://youtu.be/52Ux-m-A0O8?t=401

Thanks, I'll check that.

I realized I wrote "HP ZBook G3" in my first post, when I meant "HP ZBook Studio G3". I've got a HP ZBook Studio G3 which is why the fuse identified in the "HP ZBook G3 Backlight Fuse Location" thread can't be found on my motherboard, and also why my images differ from the images in that other thread.

So before I reassemble the laptop to make sure it's not just the ribbon cable, can anyone point out the LCD Backlight fuse location on the HP ZBook Studio G3?

 

[eccyearner]

is the video ribbon cable still connected correctly? unplug and replug on the motherboard and the display and check display light again

OK, now I've checked the video ribbon cable. I can only unplug and replug it on the motherboard side, I can't figure out how to separate the display to reach the connector in there.

Perhaps the video ribbon cable is faulty. The screen flickered to full brightness for 1/20th of a second a few times when I moved the hinges (opened/closed the display lid) but now I can't repeat that.

I've disassembled the laptop so the cooling and battery are removed, and the display is released from the base, allowing me to try to move around the video ribbon cable more to try to get the backlight to work, but without success.

So, any suggestions for next steps? Any links to instructions on how to disassemble/separate the display so I can reach the connector inside there?

Also, when does the HDMI activate? I can't get anything from the HDMI output now, so is it also affected by whatever is causing the backlight problems, or is HDMI not activated until after an OS has booted?

 

[eccyearner]

I managed to pry apart the display, and checked the connector. Looked fine to me, I unplugged and replugged it just for the sake of it. Also followed the other leads which branched off from the video ribbon cable; one went up to the webcam and the other went to a small circuit board on the bottom, close to the display connector. Perhaps it's the microphone?

Didn't see any separate backlight module. Does one have to replace the entire LCD if the backlight is broken? I remember fixing some other brand laptop (Asus perhaps) around 10 years ago where the backlight was broken, back then I ordered a new backlight module from Aliexpress and replaced the faulty one and that worked.

So, any suggestions for next steps? Is it time to get a new display? In that case I'd really like to verify it's not something on the motherboard that's broken (such as a fuse) before ordering, if anyone has any pointers.

Also, when does the HDMI activate? I can't get anything from the HDMI output now, so is it also affected by whatever is causing the backlight problems, or is HDMI not activated until after an OS has booted?

The OS won't boot and I'm having a really hard time trying to read the screen using a flashlight, to troubleshoot the boot issues. White text on black background is basically impossible to read. Black text on white background, such as the error messages one get when changing RAM och storage, can easily be read with a flashlight and it's almost readable without a flashlight.

 

[helpstar]

replace the ribbon cable

n most likely wrong boot order