Black screen on SHARP LC-55CUF8472ES TV

Question

Hello,

After some research on the internet, I couldn't find a solution to my problem so I hope you can help me!
I have a 2017 SHARP television and suddenly the screen went off and doesn't turn on anymore (there's no sound either).
I took the back off the television (Photo 1) and after looking closely, I didn't find anything broken or disconnected (the capacitors are not bulging either).
I then measured the voltages at the output of the power board to see if it was functioning normally and it seems okay since I do find the values of 12V and 5V at different points (Photo 2 and 3).
I also find these values at the input of the motherboard (Photo 4, 5, and 6).
However, I don't find any voltage at the terminals of the ribbon cable that powers the panel, so I don't know if I'm doing something wrong (Photo 7) or where the problem might be on the motherboard.
I found one on eBay but I want to be sure that is indeed the source of the problem.

Thank you in advance for your feedback and for your time.

etu_59300 · Accepted Answer

Hi,

Thank you for bringing up the topic again; it may allow someone qualified to see it and respond.
Unfortunately, changing the motherboard did not solve the problem; it is still the same... The LED lights up but the screen doesn't!

Hoping to get more responses, I continue to search...

Panth33ra · Answer

etu_59300 · Answer

Yes, exactly, I can't manage it... It shows processing but it doesn't work.

etu_59300 · Answer

Here they are! Thank you

etu_59300 · Answer

Here they are! Thank you

guibloublou · Answer

Hello,  Have you found a solution? I have the same issue since today.  Best regards

etu_59300 · Answer

Hello,

Without a response, I ordered a new motherboard even though nothing guarantees that it will work. I'll keep you updated when I receive and install it.
However, I noticed that my tests are not sufficient and that I should also check the values of the currents entering the motherboard using an external power supply, but I don't know which values I should find.
Best regards

Alex2306 · Answer

Hello, I have the same issue, did you solve the problem by changing the motherboard? Thanks in advance, Alex

Andyviking · Answer

I have exactly the same problem since today (Happy New Year!) with the same television bought in November 2017 (therefore no longer under warranty).
If anyone has a solution to the problem, I'm interested. The TV worked perfectly well until last night.
The sound works (I was connected to the DVD player when I turned off the TV last night), so I can still use the TV to listen to CDs on my DVD player, but that's not what I bought it for...
The screen is completely black, no Sharp image on startup, but the standby light changes from red to white (stable) when I turn the TV on.

Alex2306 · Answer

Hello,
In fact, the problem on my end comes from the power board and the voltage supplied for the backlight LEDs which is not correct.
Not having the schematic and not being very familiar with these power boards, I didn’t want to waste time debugging the board with a multimeter and oscilloscope (it must be a simple capacitor or transformer on the board in my opinion; if anyone finds the schematic, I’d be interested in diving into it to find the exact cause!)
I dismantled the entire panel to test each LED individually and they are all okay.
If I sit in complete darkness and turn on the TV (no light when looking through the back cover) with a flashlight on the screen, I can see a message, so it’s indeed the backlight LEDs that are not turning on (main board is okay then).
Then I should have around 150V given the number of LEDs in series, and I don’t even have 1V on the two connectors at the top right of the power board (LED inverter/driver).
I’m waiting for the power board and I’ll let you know (available on eBay for a reasonable price).
Good luck.

3Mmax · Answer

Hello, same problem for me, and I also bought it at the end of 2017 (November), so just over 3 years... last night everything was working and this morning a black screen, only the sound works
Sharp TV, first and last time for me :(

Alex2306 · Answer

I changed both boards (power and main) and still no backlighting.
I bought a LED tester to identify if I got a faulty power board or if there's a problem with the cable between the power board and the LEDs (since all the LEDs work one by one).
As soon as I have the tester by the end of the week, I will reopen everything up to the LEDs to test all that.

3mmax · Answer

Hello, thank you for your response. Do you have more information about this defective part? In particular, where is it located? What needs to be disassembled to access it?

zn · Answer

Hello, same problem for me.

Andyviking · Answer

A priori, après test au multimètre des barres de led, j'ai un led mort. J'ai commandé la barre de led défectueuse à l'unité sur Ebay à un vendeur italien. 15 € pour une barre avec frais de port, c'est toujours moins que 100 € pour l'ensemble des barres de leds vendues habituellement.
D'autant que j'ai entendu un crac au niveau de l'écran quand ma femme l'a un peu trop soulevé (plié) en m'aidant.
J'espère donc ne pas avoir de problème au remontage de l'écran et ne pas avoir d'autre panne que cette barre de leds.
Si j'ai un soucis d'écran et que l'un d'entre vous veut se débarrasser de sa télé et habite en Ile-de-France, je veux bien le débarasser de cet objet encombrant.

Par contre, vraiment pas simple de tout démonter sur cette télé Sharp...

Je vous tiens au courant si j'arrive à bien réparer cette télé.

Alex2306 · Answer

If anyone needs it, I have an LC-55CUF8472ES without an LCD panel. For sale as a lot or individually. I have two motherboards and two power boards. Feel free to contact me if needed.

Andyviking · Answer

"Without the glass" = without the screen glass?Your repair didn't hold?

Black screen on SHARP LC-55CUF8472ES TV

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