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My LG TV 55lv5500 suddenly turn black with no sound or picture.

My TV turn black with no sound or picture. The power light is on. I openness the back cover and it seems all capacitor are in working order. Do I need to replace the BU board or power supply

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Have the same TV....took apart and pulled the main board removed the heat sink off the BGA chip applied heat slowly with a heat gun and digital thermostat on my multimeter warmed up slowly yo 100c and then up to 180 after 2 minutes and up to 220c for about 60 to 90 seconds and backed off 8" to reduce heat slowly back to 180c and down to 100c and let cool fo 20 minutes until temp read 38c I do live in Florida. Reinstalled the oars added power and sure enough powered right up. Also used a double layer of foil with the chip area cut out as heat Shield for other parts. Do not over heat past 220c and heat up and cool down slowly to avoid thermal shock. Make sure your power supply is working.

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Chianti, how did you remove the heat sink from the bga chip? I don't know how to remove those plastic pins without breaking them. (maybe my setup is slightly different as I have the 47lv5500)

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@chianti19881, this procedure worked for me, too. I have a 47lv5500. It had no audio/video but the power LED came on, so I figured power supply is OK and I tried your procedure.

Took the motherboard out of the TV. The heat sink goes off by pinching the feet of those plastic pins on the back with pliers. Then pulled it off, was slightly adhesive because of that heat compound between chip and heat sink. In the end, I just put the heat sink back onto the motherboard.

I used a Makita heat gun and a cheap, analog oven thermometer. I ramped up heat slowly, then held it for about 90sec at about 400F, then cooled it down slowly to 100F and let it sit for a while. Total procedure time 10minutes. Hope this helps somebody else, too!

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I had the same problem thanks for this solution.

I heated the CPU up with my hot air solder station to 220C for 5 minutes.

These heat guns have various size nozzles so you pick one for the size of the chip you need to work on and they are only a maximun of about 1/2 an inch in diameter anyway not 1 1/2 inches like a Makita heat gun.

I did not bother with a heat shield the chip is pretty much on its own. I was more worried about the chips underneath falling off.

Went to the shop and when I came back reassembled and all working.

Obviously a problem with this series of TV's.

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I finally made time to try this solution. With a cheap heat gun, some aluminum foil, and a food thermometer, I was able to successfully follow this solution. It worked for me on my 47LV5500. We'll see how long it lasts.

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Chosen Solution

jpwinarto this sounds more like a power board issues. You do want to start by checking the power board voltages. Post some images of your boards with your question by using this guide. There are two different power boards depending on the type of LED backlight.

Block Image

and

Block Image

check the connector (red rectangle) to see if you get those voltages:

1 Power on

2 20V (24V)

3 20V (24V)

4 20V (24V)

5 GND

6 GND

7 GND

8 GND

9 3.5V

10 3.5V

11 3.5V

12 3.5V

13 GND

14 GND

15 GND

16 GND

17 12V

18 Inverter On/off

19 12V

20 Lamp : A-Dim LED : N.C

21 12V

22 PWM Dim #1

23 NC

24 Error-out.

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I replaced my LG power supply with brand new power supply and still no picture. Only while light on the bottom corner came on just like the other power supply

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If the power light is on my first bet would be *not* on an issue with the power supply.... this answer should not be the chosen solution.

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@argv I think you are perfectly right. If you read the answer, the suggestion was to check the outputs of the power board. You have to start somewhere. I am aware that this could be caused other issues. Let me hear what you think this could be.

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Hi.

I had the same trouble on a 42LX6500. TV powers on, but no video, backlight or sound. Nothing.

Checked voltages and power-on signal as explained by oldturkey03 but voltages were correct.

So, I decided to reflow LGE3556C under brown heatsink and it is working now. A professional reballing should solve this definitely.

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Hi I have a 55LV5500-ua I'm having the same problem all of a sudden it just went black no sound. what does reflow mean and where do you find brown heat sink?

Tyia

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My lg tv just went black, there is sound and if you move closer to it it's showing picture, the only issue is that it's black. How can i fix it please. And i have increased the brightness and all that, but still black.

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Kyle Bird:

Hi. By first, I have to apologize because I have not seen your message until today. Perhaps already you have solved your problem but anyway take a look at this reflowing video:

https://www.youtube.com/watch?v=hIKfvqrO...

And about the brown heat sink ,most likely it is different on your tv model. Try looking for images of the motherboard, schematics, etc.

Myrna Chapman:

Your problem seems to be on the backlight circuit. Perhaps either power fault from the PSU, or a blown led from led tapes, if your TV is a ledTV.

Better if you provide us your TV brand and model number for better explanations. Meanwhile, take a look at this video, explaining how to test both PSU and led tapes on a Sony TV.

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Model No: 32LB530A-TA

LG led tv

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jpwinarto will be eternally grateful.
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