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Anthony_Infotech
Anthony_Infotech, Technician
Category: TV
Satisfied Customers: 14902
Experience:  20+ years experience TV expert (field and bench) 9 approved qualifications in TV-ELECTRONICS
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I have an LG, 55LE5400 that powers on but has no video or

Customer Question

i have an LG, 55LE5400 that powers on but has no video or backlight
JA: Has this happened before? And have you tried unplugging your LG and leaving it off for a few hours?
Customer: yes, many times
JA: Does the TV menu work? Do you have the same problem on all sources/inputs?
Customer: right now i have the back off, so no cables are connected, just power
JA: How long has this been an issue? What happened right before this popped up?
Customer: the tv has been placed aside for 3 months since this happened back then.
JA: Anything else you want the TV expert to know before I connect you?
Customer: we were watching tv, all ok, and it went off
Submitted: 10 months ago.
Category: TV
Expert:  Anthony_Infotech replied 10 months ago.

Hello

Welcome

Is there any sound please?

If you see any messages particular ones for a phone call they are not from me but the site, I do not use the phone call facility myself, only this texting method which I consider the best way forwards, if however you want to use the phone call option this will go to a board for another tech to take up, if a tech considers this viable by phone he will ring you, otherwise if you do not want it please ignore it thanks.

Anthony

Customer: replied 10 months ago.
ok, i will work with you, and this texting process.
Expert:  Anthony_Infotech replied 10 months ago.

Is there any sound please?

Customer: replied 10 months ago.
i do not have any video connected, so i am not sure
Expert:  Anthony_Infotech replied 10 months ago.

OK you need to do that and get back to me, then get a flashlight shine it on the screen, at a 45 degree angle , continually press the menu button of the sets own remote control do you see a piece of the menu where the light hits the screen?

Customer: replied 10 months ago.
there is no display so i do not see any menus at power up. the menus would be needed to select which source
Customer: replied 10 months ago.
let me check...
Expert:  Anthony_Infotech replied 10 months ago.

Please re-read what I have asked for thanks

Customer: replied 10 months ago.
i am trying it now
Expert:  Anthony_Infotech replied 10 months ago.

OK

Customer: replied 10 months ago.
do i need the video source connected to do the flashlight abd menu checks?
Expert:  Anthony_Infotech replied 10 months ago.

No the menu is generated inside the set

Customer: replied 10 months ago.
i do not see anything ( except the flashlights reflection) on the tv when i press the menu button
Expert:  Anthony_Infotech replied 10 months ago.

OK problem is backlights are out if you see no light at all on the display even in a dark room, i must warn you that LG backlight failure ITSELF is quite common and to replace these bulbs is not easy, there are 3 boards that can cause problems all available here

http://www.shopjimmy.com/lg/55le5400-uc <<click

You MUST use the partnumbers found on your own boards to order

The LED driver board top of the page can give trouble as can the master\slave LED inverters

If you need more help let me know

Please consider rating the answer positively with the rating bar of stars at the top of the page, rating me positively enables me to receive payment from the site thank you, ***** ***** question is open for 30 days

Many Thanks

Anthony

Customer: replied 10 months ago.
wait, you mention a bulb and then the 3 boards, specifically the middle LED driver board, and then the master\slave LED inverters... where are they?
Customer: replied 10 months ago.
which is it, the bulb, the LED brd or master\slave LED inverters
Expert:  Anthony_Infotech replied 10 months ago.

Because it can be any 3 or 4 issues there is no way to check if its the lamps/bulbs for the backlights without a special tester

Expert:  Anthony_Infotech replied 10 months ago.

So we would begin by swapping out the boards

Expert:  Anthony_Infotech replied 10 months ago.

Look at the link to the boards you should see those boards in your set

Expert:  Anthony_Infotech replied 10 months ago.

All 3 boards together under $100

Expert:  Anthony_Infotech replied 10 months ago.

As I say there is no wy of knowing if the bulbs for the backlights themselves have failed

Customer: replied 10 months ago.
the 3 brds are $240 and then u say ... or it could be the bulbs?
Expert:  Anthony_Infotech replied 10 months ago.

No $112 you are adding wrong

Expert:  Anthony_Infotech replied 10 months ago.

LED driver board top $30

Expert:  Anthony_Infotech replied 10 months ago.

In fact your set may not use these further boards

Expert:  Anthony_Infotech replied 10 months ago.

It looks like they are in a later model can you see the driver board

Expert:  Anthony_Infotech replied 10 months ago.

Please consider rating the answer positively with the rating bar of stars at the top of the page, rating me positively enables me to receive payment from the site thank you, ***** ***** question is open for 30 days

Many Thanks

Anthony

Customer: replied 10 months ago.
LED brd=$30
PWR brd=$40
Main brd=$100
Bulbs= ?? what are they
You are suggesting to replace almost everything!
Expert:  Anthony_Infotech replied 10 months ago.

Who said anything about the power and mainboards?I dont mean everthing on the page just what I am referring to

Expert:  Anthony_Infotech replied 10 months ago.

Thelink is just a link to the parts for that set I dont mean replace everything lol

Customer: replied 10 months ago.
you said "all 3 boards are under $100, "three boards", this TV has 3 brds. I took that as replace all 3 brds
Expert:  Anthony_Infotech replied 10 months ago.

And as I said above you may only need the one board as the slave and master boards are in a later model so I ask again can you see the LEDdriver board??

Customer: replied 10 months ago.
Expert:  Anthony_Infotech replied 10 months ago.

OK but you cant see the other two?the master\slave boards?

Customer: replied 10 months ago.
i can see all 3 brds
Expert:  Anthony_Infotech replied 10 months ago.

All those boards I have pointed out OR there is only 3 boards in the set??

Customer: replied 10 months ago.
on left is the large pwr brd
in upper middle is the LED brd,
on right is what they call the main brd with all the video i/o conns
Expert:  Anthony_Infotech replied 10 months ago.

Can you please read carefully what I am saying?the master/slave may NOT be in the set

Expert:  Anthony_Infotech replied 10 months ago.

For $30 its worth replacing that LED driver board

Customer: replied 10 months ago.
ok, i do not see any brds that look like the master/slave.
I just see the 3 as i described above
Expert:  Anthony_Infotech replied 10 months ago.

Replace the LED driver board please

Anthony

Customer: replied 10 months ago.
the LED brd has a blue LED blinking on it at about 2 Hz
Does that tell u anything more?
Expert:  Anthony_Infotech replied 10 months ago.

No it does not I am afraid

Expert:  Anthony_Infotech replied 10 months ago.

Please consider rating the answer positively with the rating bar of stars at the top of the page, rating me positively enables me to receive payment from the site thank you, ***** ***** question is open for 30 days

Many Thanks

Anthony

Customer: replied 9 months ago.
How sure are you about replacing the LED driver board? The display is off but you really did not ask about anything else?
Expert:  Anthony_Infotech replied 9 months ago.

There is never 100% certainty with flat panel repair its all done on experience, the reason for that unlike the crt sets of years ago is there is very little that can be done to verify issues like voltage\signal checks even at workshop level we are limited because the sets are only designed with data in mind NOT signals and data is not checkable if you look at the density of the electronics you can see why the boards are stacked deep in electronic devices .....

Now getting back to your issue you asked the question originally when you had the set apart so get it back to gether get a known good signal into the set like a DVD player put a DVD in and play it, pick up the sets own remote and once every second press the INPUT or SOURCE button do you get the SOUND through?

Anthony

Customer: replied 9 months ago.
I tried the DVD test playing with sound on an other tv, but when I plugged the cables into the bad tv I still get no video and no sound while pressing the input button many times at several different rates. So no audio.
Expert:  Anthony_Infotech replied 9 months ago.

OK next checks involve a meter (because of no sound) so you will need to measure all the volt outs from the power to mainboard there should be voltages like 5vdc\12vdc

Can you do this?

Anthony

Customer: replied 9 months ago.
I already did. Every voltage that way marked was ok
Customer: replied 9 months ago.
^was marked was ok
Customer: replied 9 months ago.
What's next?