LG 55EC930V - Sound but no image - Please help

[jexpang]

Hi everyone. I am trying to fix my LG curved TV.

So i have been checking the several topics on this TV here at the forum but i am struggling into solving the issue. I am not a pro with electronics, so i will try to provide every detail i know:

- Screen is all black, i've never managed to have anything shown at it during my repair "tries"
- If i use the remote to turn it on, the "LG" led goes off after a couple of seconds.
- Inserting a USB Pendrive feeds it correctly, i can see the pendrive led flashing correctly.
- If i connect HDMI source with sound, it will play the audio, but no pic whatsoever
- Tried to follow the SMPS testing procedure, to my best knowledge all the voltages are as they should, although i have not checked comprehensively
- The Mainboard shows the red led when "turned on", but no image
- P202 24v voltages are all in good shape, measured with multimeter. No problems here.
- I've tried to get a TCON from another TV. It isn't exactly the same (i mean the board chip layout, for example it does not have the "metal covered" chip that mine has. But hey, it's from the same TV model so it should work right? But it doesn't... maybe it is also not good?
- Screen has no apparent cracks or dings

I can't seem to show anything at the screen. Always black. Tried to remove the 4 TCON LCD connectors, still black.

I don't have an IR blaster. I don't know what else to i can do.

Please someone may help?

[jexpang]

Re: LG 55EC930V - Sound but no image - Please help

No one?

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Hi, i'm too in the way with this tv. Mainboard die, never turned on even with service remote. New Mainboard, tv turned on, got horizontal lines, and Sound.
My lvds cable Was too broken. After that i got a Image finally. But first 2 Minutes it turned off. Next Boot i saw Orange lines fast flickerin in loading screen. 10 minutes it worked. After that i'm only able to turn with service remote. But... few seconds later, half side goes dark...
What happens in you remove one flex cable into panel ? Do you See green for 2 seconds?

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Hi, i'm now on my Computer, it's hard to write on phone haha.
Do you have pictures of your LG ?
And please a good Picture of your LVDS Connector.
I will upload some images, where my LVDS cable was broken. ( i broke it lol)

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Ok, here some Images.
This green Line Image happens because my LVDS cable was missing. Maybe your LVDS has a little damage, that the screen is dark. i don't know.
Or you Image Driver is sleeping, like someone said in this forum. i read, it helps if you plug in a USB Stick with a video in mp4, and a mouse. then you have to click often the mouse buttons and move it.

[jexpang]

Re: LG 55EC930V - Sound but no image - Please help

@TeslaMichael thank you a lot for your replies!

If i disconnect the LVDS cable out of the TCON board, and turn the TV on, i keep hearing clicking noises every second or couple of seconds - before it didn't do that. But the screen is still black as hell - no change whatsoever. The LG logo light, doesn't turn off, however.

So here it is a pic of the whole board set and two pics of the LVDS cable. Everything seems alright i guess?

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Looks like the cable is not perfect in the connector. Did you remove it often already ?
If my lvds cable is connected, i see no metal body of the cable, only all black. I try to upload a picture from my phone.
And I don't know if it matter if you remove lvds from t-con or Mainboard side. But i can say, my TV was running when i removed the lvds cable. But the first try to turn it on didn't worked. I had to try again to power on.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

My new lvds cable, should look like this.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Btw. Do you have Old Phone with IR Blaster ? I have a old galaxy s5. The galaxy s6 also have a ir blaster.
Then you could get also into the Service menu, but need a app. I Use app RCOID. (Power only with in_start.) With this way i also get out of the lockmode/safemode. (3 failed starts = locked)
But there is also a cheap way, you could get a service remote from ebay for LG tvs.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

And how did you measure the voltages with the multimeter?
I have to measure my LG at the T-con, but don't know if it's safe. I don't want to break my TV ^^

[jexpang]

Re: LG 55EC930V - Sound but no image - Please help

Looks like the cable is not perfect in the connector. Did you remove it often already ?
If my lvds cable is connected, i see no metal body of the cable, only all black. I try to upload a picture from my phone.
And I don't know if it matter if you remove lvds from t-con or Mainboard side. But i can say, my TV was running when i removed the lvds cable. But the first try to turn it on didn't worked. I had to try again to power on.

Interesting. I had never removed it before, so i guess they have installed it like this when assembling the TV. Maybe this cable is not the cause of the malfunction, even if has some bare metal showing

My new lvds cable, should look like this.

Yes, it definitely looks different from yours. I'll keep an eye to try out another cable if everything else doesn't work.

Btw. Do you have Old Phone with IR Blaster ? I have a old galaxy s5. The galaxy s6 also have a ir blaster.
Then you could get also into the Service menu, but need a app. I Use app RCOID. (Power only with in_start.) With this way i also get out of the lockmode/safemode. (3 failed starts = locked)
But there is also a cheap way, you could get a service remote from ebay for LG tvs.

Unfortunately i my phone has not an IR blaster. I will probably get a LG TV Service remote as i have more than one LG TV. Can you advice me on the cheaper site to buy it?

This step will be my first option: get the TV out of the locked mode. Is there any way i can unlock it physically? I mean, with a jumper or something? I had an old LG monitor in which i could do that. That way i wouldn't need to wait for the LV service remote to arrive..

And how did you measure the voltages with the multimeter?
I have to measure my LG at the T-con, but don't know if it's safe. I don't want to break my TV ^^

I've measure the current output of the power board connector to the T-Con, , as part of the SMPS procedure at P202 socket. Every pin was providing the correct voltage. Half of these pins should be providing 24v, the other ones are ground. So just put your red pincer on each of the 24v pins and the black pincer on the ground pins. It should read around 24v. You have to be careful not to short any of the pins with any sloppy movement of the pincers, otherwise you may well fry the board.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Hi, i have not enough time to anwers everything, but there is only the way to get out of the protection with a service remote or phone app that simulates a service remote. maybe you see the TV working again, but will turn off in minutes.
If i unterstand it now correct, the TV is not booting anymore, it is cancelling the boot?
Because you wrote at start of the Thread that you can hear the sound.
If the tv isn't booting anymore, then there is definetly the lockmode in the game. or better to say, protection mode.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Will answers tomorrow the other questions

[jexpang]

Re: LG 55EC930V - Sound but no image - Please help

Yes the TV is not booting (at least i see nothing). Still, when plugged to a HDMI source it plays the sound, yet the screen it's pitch black. I believe that the main board is good as the HDMI sound extraction and Digital-Analog conversion is working. I suppose it is also decoding the video but for some reason the panel is not working at all.

I've just ordered an LG Service remote. I'll wait untill it arrives to do further testing.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Hi, Okay, this means your light goes off and is off when TV is running? So the TV is working but the Panel doesn't show anything.
You said, if you remove LVDS cable, the TV won't start/boot.
If you try it twice, then does it boot ?
For me when i removed it, then first start wasn't succesful but the next try was a succes.
And if it does boot without LVDS cable, then try to remove one of the four cable that goes from Panel into t-con.
Then try again, and then you should see maybe when TV is starting or booted, a bit of green color. maybe the room should be not bright, to see it better.

But even if it's not booting, you should see green color after start before it goes off after 3 seconds
btw. you could use a mouse on the TV to see when he is ready to use. Mouse should light.

[GAStuntman]

Re: LG 55EC930V - Sound but no image - Please help

Have you tried using a backlight tester in the tv? Normally when I get a tv with sound & no picture the issue is back lights.With some models such as the LG TVs there is an issue with the main board as well.

[mmartell]

Re: LG 55EC930V - Sound but no image - Please help

Have you tried using a backlight tester in the tv? Normally when I get a tv with sound & no picture the issue is back lights.With some models such as the LG TVs there is an issue with the main board as well.

This is an OLED - does not apply.

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Do you have already the Service Remote ?

[jexpang]

Re: LG 55EC930V - Sound but no image - Please help

Yes! Finally it has arrived. So what should i do now?

[TeslaMichael]

Re: LG 55EC930V - Sound but no image - Please help

Okay thats good. What happens if you press the Power Only button ?
The tv should start with a white screen. And the lg logo should be bright if he is on, in power only.
You leave the mode with the the key exit and power off. Then the tv turns off.