Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Hi all,
I have replaced all the LED strips and the picture is lot better than before. But I could still see "faint" crosses in the picture when there was gray background?
Is it possible that maybe the power supply board is supplying a little bit too much voltage and hence the LEDs are too bright causing the non-uniformity backlight?
Has anyone come across this issue with full-array LED backlight?
Wildwind
Member
Last Activity: 05-14-2017, 06:14 AM
Joined: 05-16-2012
Location: Melbourne
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Yes, I used the 3 holes from the old black glue as guides. You can vaguely see the 4 bright spots with the old LEDs as well.Leave a comment:
-
Re: Samsung LA55A950 55'' with fuzzy lines until warmed up
Regular horizontal lines in whole picture but become perfect after the set has warmed up....Last edited by Wildwind; 01-09-2017, 08:02 AM.Leave a comment:
-
Samsung LA55A950 55'' with fuzzy lines until warmed up
Hi all,
My friend's Samsung LA55A950 55'' TV has horizontal lines in the picture and they go away after the set has warmed up. Lately, it's taken longer for the lines to go away. Is the T-con board or Power Supply board or worst mainboard doing this?Last edited by Wildwind; 01-09-2017, 08:01 AM. -
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Nothing printed on both LED beads. The PCB pads on the LEDs are identical to the LG ones though. I'm getting some from another seller (1.2W, 6V, 120lm) and he reckons that the others are selling fakes (I bought 2W, 6V, 150lm earlier). I will compare the two and let you good folks know if the new ones are a better match.
This is a global team effort with an Ozzie, UK, USA team
...
Last edited by Wildwind; 01-09-2017, 07:37 AM.Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
No, picture is clear and it's a spinning logo and the camera had trouble in low light with the shutter speed....Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Yep, 127V in VDC meter reading. It could be the PWM causing the multimeter to read such low value.
Could there be something wrong with the power supply board?
I gave attached a photo of the backlight distortion. You can still make out the distortion with the original LEDs as well. This project has taught me quite a lot about LED CD TVs (with a lot of the forum posters' help)...
Last edited by Wildwind; 01-09-2017, 12:41 AM.Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
I measure the Vf of the LED circuit and its was constant at 127V with various backlight settings.
I think I live with it and will wait for some cheap 2nd hand strips to come up for sale...
Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
It is a stupid back-light design to connect ALL the LEDs in series (like the Christmas decorative lights) so if 1 fails (open circuit) then the whole thing is dead. Putting a resistor in across the LEDs will work but it is too tedious. If I have to open it up again then I might as well replace them with the correct LEDs...
Last edited by Wildwind; 01-08-2017, 10:00 AM.Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
I bought these 6V LEDs from AliExpress. I think all sellers are selling the same LG Innotek LATWT391RZLZK LEDs. Some how these ones are a bit brighter then the original LEDs.
Does anyone have the datasheet for the LG Innotek 3535 6V LEDs?
[url]https://www.aliexpress.com/item/LG-Innotek-LED-LED-Backlight-2W-6V-3535-Cool-white-LCD-Backlight-for-TV-TV-Application/32643527631.html?spm=2114.13010608.0.0.PNnvfE[/url]
The measured LED backlight voltage was 211V which is a bit higher than 192V...Last edited by Wildwind; 01-08-2017, 07:35 AM.Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
This the the strips for my model but there are out of stock. They are 6V, 200mA LEDs
[url]http://www.shopjimmy.com/lg-6916l-1709a-6916l-1710a-led-strips-8-strips.htm[/url]Re: LG 42lb5820 Won't Turn On with 3...rips.htm[/url]...Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
I got some Innotek LEDs from China (which looked very similar to the original ones) and installed them individually (using SMD heatflow workstation) and glued the lens back on using superglue as I had a bit of spare time to play around with it....
Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Thanks for all the replies. ShopJimmy did not have the strips for this model in stock (for quite a while now). Even the old LEDs (less bright) still had some non-uniformity when I looked closely so it is a bad design from LG then
Have any of you come across an LED LCD panel with a reflector film between the diffuser and LCD panel (as some models on YouTube did not have it)?Last edited by Wildwind; 01-06-2017, 08:41 PM.Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
UPDATE: I managed to buy a second hand mainboard (from a 50LB5820) and it worked OK. However, there was a bit of non-uniformity as the new LEDs were a bit brighter than the old LEDs and they came through to the picture.
And I was wondering if I the installed the diffuser and the thin reflective film inside the panel wrongly. I did not think it was the case if there were back to front/up side down etc. then the clip/screw holes would not line up as they should act as aligning holes.
Does anyone...Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
UPDATE: I got some replacement SMD LEDs and managed to replace all the dead ones. The LED backlight still would not come on (DRV_ON = low) so the mainboard is faulty as well. It came on when I manually pulled it HIGH so the PS board is OK. Already tried to re-flow the main IC but it did not help
I have the wait for a PAL mainboard to come on eBay...
Leave a comment:
-
Re: 40" Samsung UA40C6900 with washed out picture
I think it has this T-con board....Leave a comment:
-
40" Samsung UA40C6900 with washed out picture
Hi all,
Great forum
I have a Samsung UA40C6900 with washed out picture. is it a T-con board issue or panel issue?
Also, what is the fault when the whole screen is white with no picture at all?
Thanks all....Last edited by Wildwind; 11-01-2016, 05:36 AM. -
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Thanks for the info Budm
Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
Do you know if the the DRV-ON pin would go high if there is an open circuit in the LED string?
Is the P-DIM input or output from the mainboard?
I have opened up the display and found quite a few (11) dead LEDs and I will replace them individually using a SMD/heatgun workstation
Also, if the main CPU is dead would the TV still respond to the remote control?
Thanks....Last edited by Wildwind; 10-21-2016, 09:25 PM.Leave a comment:
-
Re: LG 42lb5820 Won't Turn On with 3 Blinking Red Light
That was what I was afraid of (dismantling the LED assembly).
BTW, I did a voltage measurement between the +ve and -ve terminals of the LED connector and it never went very high as though both pins went high together. Should I tie the -ve pin to ground (without the m/b connected test) to make sure there is a high-ish potential difference between them.
Sorry for all the noobie questions as I am curious on the new LED LCD TV technology. I have substantial knowledge in electronics...Last edited by Wildwind; 10-15-2016, 11:24 PM.Leave a comment:
No activity results to display
Leave a comment: