HELP! Dell inspiron 7547 LED no back-light after replacing LED screen and probably a blown fuse.

Hi Guys, My problem is similar to thread http://www.tomsguide.com/answers/id-3206844/dell-inspir...

Context : After replacing the screen on my Dell Inspiron 7547, i'm not getting backlight, although on seeing with a flash light i can see that the display is working and also being detected via windows.I'm using an external monitor and it works fine.

Things tried without success (mean no backlight):
1. Remove battery and discharge fully.
2. Change display cables.
3. Diagnostics test at bootup (Pass)
4. Dell support assistant Graphics card test. (Pass)
5. Re-seat the ram. (Pass)
6. All hardware BIST tests. (Pass)



More details on what has been done.
https://www.reddit.com/r/Dell/comments/8bsihf/inspiron_...

I've two display cables and 've confirmed that they both work well on the new screen but without backlight.

Now i've an original replacement of the screen i.e B156HAT01.0 40 Pin
But no backlight.

My motherboard reads DAOAM6MB8EO Rev:E

And i've also found semantics ( https://www.dropbox.com/s/l05mz9mkmgv76b6/vinafix.com_Q...) for my board. Unfortunately i don't know how to read this properly but looking back and forth the previous mentioned thread and proposed solution i'm trying to find the fuse for my board.

I've short listed few.
U23, C576/574.575, C580/C581/C579, C583 and R403.

If someone can help me read the sheet, i'd be able to solder (jump) the blown fuse and get it working.

Thanks for your time and help.

 

Hi, I can give you my experience with diagnostics backlight problem on Inspiron 7347 (13' display). In my case display (propably LED driver) was dead but maybe my suggestions it helps.

Here is my display with eDP connector:


You can check LED supply voltage on eDP connector (in my case 30pin):


If voltage is OK maybe display fuse blown-up. On my display fuse is located on PCB next to eDP connector under "Do not touch" tape (copper tape over black plastic tape):


If supply voltage is not OK, then display do not have fuse or there is activated motherboard fuse. Motherboard fuse i my Inspiron is located at the bottom of the board:



This fuse is self recoverable so if there is no more overcurrent it works again.

 

Sadly the pictures are no longer available. Is there a chance someone made a backup of them?

U23 is a voltage regulator, C574-C576, C579-C581 are capacitors, and R403 is a resistor. None of them are fuses.

I tried finding the fuse from the schematics and the only one I can find is for the keyboard backlight (FS0) and the HDMI (HDMIF0) .... Maybe there is actually no fuses for LCD for the Inspiron 15 7000 line?

EDIT: I think I found itsvikg's solution here: https://devrant.com/rants/1392280/s...ad-laptop-motherboard-semantics-sheet-in-shor

The problem was a faulty Q25 (AO3413)