Re: LG 65UJ6200 4K Smart TV Backlight Issue
Okay, I have reduced the backlight to 60% and its working fine now.
Thanks...
Anooc7
Member
Last Activity: 08-16-2023, 10:58 AM
Joined: 06-23-2021
Location: Halifax,NS
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LG 65UJ6200 4K Smart TV Backlight Issue
Hi all,
I have this lg 65 Inch TV with intermittent backlight failure. If it works for 1-3 hours without any issues a power on-off will trigger the issue. There is images I am attaching showing the voltage reading I got when everything works. I found a reset button on the main board that resolves the issues by pressing it. So I drilled a hole on the back to put a pencil through it to activate the switch. Checked the backlight strips and it all shows exact same voltages. Any inputs? Thanks... -
Re: RCA RLED6090 backlight goes affter 10 minutes
For those who have similar issues here is the fix, I have added 3x 0.6 ohm 2 watt resistors (I didn’t have any 2ohm single ones) in series with R5501 and It works great. Your human eye will never notice any difference at all , and its brightness setting is still in the middle and sufficient for my happy client . I did increase the brightness to 80% and it still worked without any issues.Leave a comment:
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Re: RCA RLED6090 backlight goes affter 10 minutes
Thank you so much, I will try to modify the current sensing resistor. So do I need to increase its value? (It is a 0.8 Ohm resistor so how much do I need to change its value? )The customer is happy to repair it cheap but he need a bit more brightness than eco.
Thanks...Leave a comment:
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Re: RCA RLED6090 backlight goes affter 10 minutes
Yeah , so true. Since every strips works I wouldn't be able to find the faulty one too unless I have a single oem strip to replace, and its a headache....Leave a comment:
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Re: RCA RLED6090 backlight goes affter 10 minutes
I couldn't find the schematic, very unfortunate on that....Leave a comment:
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RCA RLED6090 backlight goes affter 10 minutes
Hi,
I have this rled 6090 led tv which has this backlight issue, When I change it to energy saving mode and tv works fine , All the other mods has this issue. I have entered the service menu by pressing input + 2580 and reduced the backlight to 50% . But as soon as I exit from that service menu it goes back to higher levels. (Since there is no options to save it) . There is a small ic near led drive section a dual opamp , as358m . Is it serves as a controller for backlight? How do I reduce the backlight level using an increased current sense resistance or something like that? The psb is... -
Re: Sharp LC-42LB261u LCD TV flickers more while increasing backlight
Absolutely, It was the faulty leds , replaced 5 of them. TV is working fine, told the customer to limit the bl level.
Thanks...Leave a comment:
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Sharp LC-42LB261u LCD TV flickers more while increasing backlight
Hi,
This particular TV (LC-42LB261u) flickers more as I increase the backlight from ~10% onwards. Please find the attachment. Is it the backlight leds? I changed the 3 capacitors shown in figure, but still the issue remains the same. When it blinks I can hear a buzzing noice from the big o/p transformer. I checked the two led lines with backlight testet and both showing ~ 25.xx volts . Any inputs?
Thanks... -
Re: LG 60LB5200 No power , completely dead
That is a good input , but
I have already closed the unit and decided to order a replacement psb, when it comes I will do a side to side analysis and will post the findings.
Regards...Leave a comment:
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Re: LG 60LB5200 No power , completely dead
I jumped r33 but still issues remains the same. Before ordering a psb this was the only experiment remaining, I doubt the purchased IC’s quality at this moment, but not taking chances anymore.
Thanks all for your time.Leave a comment:
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Re: LG 60LB5200 No power , completely dead
From the schematic it is labeled as 103 , I found from a previous forum posting that its a half watt 10k resistor....Leave a comment:
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Re: LG 60LB5200 No power , completely dead
Update: So I hooked the psb to main board and the voltages (24 and 12 outputs) dropped to 4.2v and 2.2v (where it was 16 and 8 before). I checked the r33 resistor (10k)that I replaced and it is showing Mega Ohms.
I am including a practical circuit which I found from the data sheet of Tea1755t ic , there is no resistance in between the hv sens pin and the transformer, so can I short that with a jumper? (Instead of r33)...Leave a comment:
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Re: LG 60LB5200 No power , completely dead
I checked them in diode mode and found that the N-channel mosfets are conducting properly so as the diodes and resistors.
I will update if this setup works with attached main board.
Thanks...Leave a comment:
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Re: LG 60LB5200 No power , completely dead
No, it is not connected to the main board at this time. The voltage across c25 is 15v and across c51 is 20v . I am going to connect the psb to main board soon.
Thanks...Leave a comment:
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Re: LG 60LB5200 No power , completely dead
8 and 16 volts respectively. The IC is carefully soldered, and it is not burning that r33 resistor like before....Leave a comment:
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Re: LG 60LB5200 No power , completely dead
I checked before measuring the volts, they are fine....Leave a comment:
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Re: LG 60LB5200 No power , completely dead
Q8 - 1 and 3 pin shows few milli volts, 2- where d12 meets - 170v the other side of diode - 169.5...Leave a comment:
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Re: LG 60LB5200 No power , completely dead
Hi, I replaced the IC but still showing less voltage on the 24 v and 12 v connection, as well as 169 volts at the 400v places.
Any inputs at this point?
Thanks...Leave a comment:
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Re: Samsung UN75NU6950 no backlight but leds works when checked individually!
The tv is not here atm but it was few milli volts to 1v I remember....Leave a comment:
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