Sony Vaio PCG-71911M faultu screen backlight

Recently the screen started going black when moving it and as of today it is completely black.
When I shine a flashlight I can see my desktop, so it is definitely the backlight.
As this is an LED screen there is no converter, so it must be either the screen itself or the screen cable maybe?

Is there a way to find out which part is causing the problem?

Thank you.

 

Hi CYPER,
I wanted you to know, I think I am looking
at the fuse on top of your motherboard.
Similar to my posted pik - where mine has a Z or N on the fuse.
I don't think it's the one you are looking for - though I'm unsure.
That fuse position - near that connector - was not the one I needed.

Here's my thought,
Look for a smaller one near the very LVDS connector
top or bottom of the board - I suspect bottom.
As others have said - clear piks of top and bottom near the LVDS Con
are needed.

I think you will find ngvuanh is the brain here - his posts got mine working
through his methods.
There is a redundant fusing - meaning a fuse on the display panel and
one on the board - so to short or solder over the fuse on the board
won't stop the protection from being in the curcuit.

It seems in most cases to be a much smaller fuse top or bottom
of the board and always close to LVDS Connector, with the designation
F16 - F15 - F14 or similar (listed in other posts) seems to always be near
the correct fuse
.
Your panel works - though no backlight - post clear piks of the
board - both sides near the LVDS Con to get clear help.

Here's hoping you find a positive result ..Tom

 

Thank you for you post.

Here are clear pictures: imgur: the simple image sharer

Click in top left corner for full resolution.

Thank you.

 

Excellent piks, though the back of the board
will surely help,
please understand my experience
with laptops does not meet that of other techs here,
I'm learning fast.

I'm still lightly sure after picture searching, the fuse is not
on top - here's hoping other techs chime in.

Please send board back piks, I will check tomorrow as
it is 10:30pm here and must work early am.

Will be happy to help if I can,
Goodnight & Happy New Year to all ..Tom

 

Most if not all pictures from the other thread show this side of the board I believe.
I am going to bed now, so will check back tomorrow for any new posts.
I haven't removed the board from the laptop, but if needed I will do it.

I will probably buy a faulty screen of Ebay (with cracked screen, but working backlight) and test with it first to make sure it is not the screen backlight at fault.

 

^^^^^^^^^^No need for all that just check to see if the fuse is blown with a multi-meter, if it is then you need to bridge or replace the fuse. If the fuse is not blown then your screen either is bad or the fuse on the back of the screen has blown and not the one on the motherboard.

 

I have a multimeter, but how do I check it exactly? DC Voltage or Continuity? When laptop is ON or OFF?
I did a resistance test and it starts from 6MoHm and goes all the way to 11MoHm. But the readout was not very consistent.
I also tested for Voltage, but I am unsure how to test each end. I touched one probe at one end and the other probe on the other end it read 18.26V. When I swap them around it goes to -18.26V.

I also won an auction for a cracked screen on Ebay, so will test with it when it arrives.

 

Use continuity, if the fuse is blown it will either read 0 or show error or no reading on multimeter. LAPTOP SHOULD BE OFF, UNPLUGGED AND BATTERY REMOVED before taking it apart -------------- not doing this also results in possibly blowing other fuses and more damage.

http://www.ehow.co.uk/how_7590933_check-smd-fuses.html

 

Pardon the late reply
I agree - most show board topside -But-
where the fuse is ? must be determined
before you can test it.
It has been stated many times in this 26 page (so far) thread - Both
sides of the Board need piks for this - two boards at least, in this thread
required board bottom repair.
Also the correct fuse for several has been near the F16 or similar
Board Designation.

 

Does anyone knows where is that fuse for sony vaio same model,same problem.