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 LG SJ800T back light issue?, Need advise

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TSost1007
post Nov 12 2017, 07:34 PM, updated 7y ago

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Hi, recently I just purchase lg 49sj800t. Yesterday night I found out the back light change constantly when the movie play. Not sure is that normal or the defect or the tv. Please check the link below. Seriously need advise from expert here. Thanks.
https://youtu.be/UIQlvCSGFJg

This post has been edited by ost1007: Nov 12 2017, 07:35 PM
AVFAN
post Nov 12 2017, 08:20 PM

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QUOTE(ost1007 @ Nov 12 2017, 07:34 PM)
Hi, recently I just purchase lg 49sj800t. Yesterday night I found out  the back light change constantly when the movie play. Not sure is that normal or the defect or the tv. Please check the link below. Seriously need advise from expert here. Thanks.
https://youtu.be/UIQlvCSGFJg
*
this is using the tv's usb player?

that video u used... may not be exemplary, i have tested that and other variations... looks too dark, right?

anyway, i can see clicking throughout the 1 min... why?
TSost1007
post Nov 12 2017, 09:13 PM

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QUOTE(AVFAN @ Nov 12 2017, 08:20 PM)
this is using the tv's usb player?

that video u used... may not be exemplary, i have tested that and other variations... looks too dark, right?

anyway, i can see clicking throughout the 1 min... why?
*
The movie was played by using smart share app from pc to display to tv. The video clip I'm simulating the changes of back light when clicking on screen. Actually I tested with other movie, if movie with a lot of black scene, the problem looks obvious. The problem less obvious and hardly to detect with colorful picyure..
See the picture (attachment)below. Is that normal? Right side backlight seem brighter.... Actually I encounter this problem throughout the movie... It shows bright backlight randomly.in the area of the led.


Attached thumbnail(s)
Attached Image
TSost1007
post Nov 12 2017, 09:16 PM

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FYI. I tested with HDR movie
AVFAN
post Nov 12 2017, 09:44 PM

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QUOTE(ost1007 @ Nov 12 2017, 09:16 PM)
FYI. I tested with HDR movie
*
i do not have all the equipment and sources to test all of HDR, still experiemneting... but i will say, from what u described so far:

.. u r playing an ahem video from pc and casting to tv... questions about your pc and casting capabilities...
.. those files are ahem ripped, u never know how good or poor they are; try diff versions.. 10GB, 50GB., 90GB ones.
.. your tv... i dunno much but this strikes me... notice the use of words "supports", "compatible" and "optimizes"?
a true HDR Dolby Vision TV will not put it that way.
QUOTE
LG SUPER UHD TV supports premium HDR content mastered by Dolby Vision™
and is also compatible with generic HDR10 and HLG. LG’s Active HDR™ technology optimizes HDR picture scene by scene for a life-like viewing experience.
http://www.lg.com/in/tvs/lg-49SJ800T


those diff shades of dark and bright are normal with HDR videos in general.
the only way to truly test it is to use a genuine 4k HDR BD played thru a BD player to your TV.

my own experience... HDR is inherently dark, need to max out backlight, play with contrast.
if u play the better HDR files with a good player, with good player and tv settings, it can come out very nice!

read this:
http://www.hdtvtest.co.uk/news/4k-vs-201604104279.htm
olak329
post Nov 12 2017, 09:47 PM

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looks like backlight want to go kaput, try change source, if same problem most probably going kaput soon
TSost1007
post Nov 13 2017, 01:46 AM

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I tested streaming another video by youtube.
Here is the result.
https://youtu.be/XfkifPe-OdI


Fusion
post Nov 13 2017, 02:14 PM

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hi...i got the same TV

this is the TV backlight local dimming issue. The local dimming uses Edge-lit which the light source comes from the top and bottom of the TV and its divided to several vertical segment. when areas meant to be black, they will off the segment but when there is a bright area (example; mouse cursor), the whole segment from top to bottom will lit up. this is why you will see vertical grey.

they use this technology to increase the contrast so that you get a darker black but LG implemented it real bad. you can off the local dimming feature so that you will not have this problem but black will look grey once you off it.
TSost1007
post Nov 13 2017, 03:48 PM

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QUOTE(Fusion @ Nov 13 2017, 02:14 PM)
hi...i got the same TV

this is the TV backlight local dimming issue. The local dimming uses Edge-lit which the light source comes from the top and bottom of the TV and its divided to several vertical segment. when areas meant to be black, they will off the segment but when there is a bright area (example; mouse cursor), the whole segment from top to bottom will lit up. this is why you will see vertical grey.

they use this technology to increase the contrast so that you get a darker black but LG implemented it real bad. you can off the local dimming feature so that you will not have this problem but black will look grey once you off it.
*
Thanks bro... tonight I will try to turn off the Local DIM setting and check how's the condition.

By the way, what you rate the TV after owning for months?

This post has been edited by ost1007: Nov 13 2017, 03:50 PM
TSost1007
post Nov 13 2017, 03:49 PM

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QUOTE(AVFAN @ Nov 12 2017, 09:44 PM)
i do not have all the equipment and sources to test all of HDR, still experiemneting... but i will say, from what u described so far:

.. u r playing an ahem video from pc and casting to tv... questions about your pc and casting capabilities...
.. those files are ahem ripped, u never know how good or poor they are; try diff versions.. 10GB, 50GB., 90GB ones.
.. your tv... i dunno much but this strikes me... notice the use of words "supports", "compatible" and "optimizes"?
a true HDR Dolby Vision TV will not put it that way.
those diff shades of dark and bright are normal with HDR videos in general.
the only way to truly test it is to use a genuine 4k HDR BD played thru a BD player to your TV.

my own experience... HDR is inherently dark, need to max out backlight, play with contrast.
if u play the better HDR files with a good player, with good player and tv settings, it can come out very nice!

read this:
http://www.hdtvtest.co.uk/news/4k-vs-201604104279.htm
*
Thanks for the advise... Appreciate... Maybe I will look for another source to test on the TV.
Fusion
post Nov 13 2017, 05:11 PM

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QUOTE(ost1007 @ Nov 13 2017, 03:48 PM)
Thanks bro... tonight I will try to turn off the Local DIM setting and check how's the condition.

By the way, what you rate the TV after owning for months?
*
the reason why i bought this camera is not because of picture quality. this is my living hall unit and my aim is for a wide viewing angle. the LG IPS screen has one of the widest viewing angle (except for OLED).

Pro:
Wide viewing angle
Very user friendly smart system
can download LG software on computer and share any movies from the computer to the TV if its in the same network
very accurate color reproduction (i use the ISF Expert setting)
Has a lot of setting for a image calibration

Con:
Contrast Ration is not very good
horrendous HDR quality
stupid local dimming

if you off the local dimming, the image quality is quite acceptable with lights on but quite unbearable when the room is in total darkness. all the blacks are actually grey.

AVFAN
post Nov 13 2017, 06:08 PM

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QUOTE(ost1007 @ Nov 13 2017, 03:49 PM)
Thanks for the advise... Appreciate... Maybe I will look for another source to test on the TV.
*
if u try enough of them, u will see the diff.

i also suggest u try some 2160p 10bit SDR (not HDR) on your tv - u can then see the diff too.

typically, the small files are crap. tongue.gif

again, try adjusting the settings in yr tv and player - usually can find the sweet spot for the better files.

with many new tv's now claiming HDR, DV... so many boxes claiming same... and all kinds of HDR files, good and crap...

i think this issue will not go away anytime soon as more and more people get into it.
Mr_47
post May 17 2018, 11:56 AM

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From: Bora-bora u jelly? Special: Age of multi-monitor



backlight...my tv LG led, it works ok, then after about 20-30s the backlight fails...sound still works and you can see the image but super dark


 

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