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Old 10-29-2020, 01:02 PM   #1
fixitjunkie
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Default LG 47LA6200-UA No Picture - has audio

I recently fixed my Samsung plasma with the help of RJ and TV Timmy so I decided to try another project. This LG 47" was given to me by a friend. When I opened it up, the HDMI IN 1(ARC) input jack fell out. I'm guessing this is probably not the cause. All of the caps look good. Any feedback is appreciated. Thanks.
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Old 10-29-2020, 11:29 PM   #2
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Default Re: LG 47LA6200-UA No Picture - has audio

You said no picture. Do you get backlight or audio? If you turn the TV on and put a flash light onto the screen, do you see picture? You may need to turn off the lights and the picture will be very faint. You may also have a very quick half second flash from the screen as well.
These TV sets use backlights that often fail.

https://www.nickstvs.com/store/p2388/LC470DUE-SFR1.html
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Old 10-30-2020, 12:03 AM   #3
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Default Re: LG 47LA6200-UA No Picture - has audio

Maybe start with testing the voltages at the connector on the powerboard with the cables all hooked up, it's the connector that the cable from powerboard to mainboard hooks into, most times there's a legend/map nearby that gives the expected voltages, you measure them with your mutimeter, set meter to 20 vdc then report them, put neg probe on chassis metal ground, pos probe on pin of connector, measure in standby take note, leave probes where they are then power on tv and again take note of voltages, report them here, example pin 1-ps-on-0 volts standby-power on-3.3 volts.
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Old 10-30-2020, 12:04 AM   #4
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Default Re: LG 47LA6200-UA No Picture - has audio

Video demo: https://www.youtube.com/watch?v=4v8DcqCNG4A
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Old 10-30-2020, 06:22 AM   #5
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Default Re: LG 47LA6200-UA No Picture - has audio

Thanks nomoresonys and Nick's TV! It's doing exactly what you described Nick. I get the flash of the LG logo then the screen is dark but picture is there and can be seen with a flashlight. How difficult is the backlight replacement?
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Old 10-30-2020, 03:32 PM   #6
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Default Re: LG 47LA6200-UA No Picture - has audio

It's disassembled. Will order the LED's and see what happens.
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Old 10-30-2020, 03:37 PM   #7
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Default Re: LG 47LA6200-UA No Picture - has audio

The backlight replacement is unfortunately the most time consuming repair in a TV since you do have to completely take it apart.
that being said it's not all that tricky as long as you keep your screws and parts organized properly during the dissasembly.
I don't have a video available for you for the entire dissasembly, but shopjimmy does below:

https://www.youtube.com/watch?v=B7o-P7yXa3I
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Old 11-02-2020, 07:56 AM   #8
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Default Re: LG 47LA6200-UA No Picture - has audio

Just thinking, is the backlight circuit designed such that all the LED's go out if just one LED fails? If not, I may have jumped on this fix too fast instead of
checking for power going to the LED's.
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Old 11-04-2020, 10:34 PM   #9
Nick's Tvs
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Default Re: LG 47LA6200-UA No Picture - has audio

Most likely 1 of the leds is out and only just 1. Only replacing 1 would fix it technically.
I do not recommend only replacing 1 LED or even 1 strip. As a rule of thumb, if you have 1 bad LED's you have to assume all others are on the brink of failure. Opening up the TV set down to the LED strips is enough work that you don't want to do it again if you don't have to, and trust me you will have to if you only replace the singular LED or strip that went out.
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Old 11-05-2020, 02:10 PM   #10
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Default Re: LG 47LA6200-UA No Picture - has audio

Replaced the LED's with excellent quality replacements from Nick's TV. IT'S FIXED!!. Thank you nomoresonys and Nick's TV. Another TV to hang in the sports book!
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Old 11-05-2020, 02:53 PM   #11
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Default Re: LG 47LA6200-UA No Picture - has audio

Glad to hear it nice work, another save.
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Old 11-05-2020, 03:02 PM   #12
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Default Re: LG 47LA6200-UA No Picture - has audio

Good fix, make sure to turn down the backlights level (Not Brightness) to as low as possible on all inputs, also turn off any auto backlights settings, it will extend the life of the LED's.
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Basic LCD TV and Monitor troubleshooting guides.
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Inverter testing using old CFL:
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