Hello again my dear friends here we are back with another video more electronic Núñez tutorials
And how can you see here again we have an LG brand screen
This is a big 49 inch screen
Which is also representing a common breakdown very well
There as you can see the TV apparently already lit
But we have the typical absence video failure
Very well very well at first glance we can realize that the backlight has been activated correctly
But we have this missing image failure
Already in previous videos I have taught them that in these cases if we make slight blows
To the panel you can see white flashes which would indicate that
The T-Con card if you are receiving power supply voltage But here I can definitely define the T-Con card
is not working so the TV is not generating the corresponding function
Then gentlemen we will follow the repair process in order to seek to resolve the breakdown
On this screen so you can keep an eye on the video so you could learn what we're going to do
To solve this breakdown. Very well gentlemen and have not subscribed to the channel I invite you to do it
And that activate the notifications bell so that no video is lost to the channel
muy bien el modelo de este televisor es 49LF5100
Then we will proceed to disarm it and then continue with the tutorial
Very well how can you observe and we have disarmed and we see that this TV is one of those who use
An external source despite being a large screen simply uses an external source now well
With respect to having and that TV we already see that the backlight is activating correctly
So in this situation and as I mentioned we are going to focus directly on the T-Con card
And in it because what you have to do is check the power voltages in this case as the voltage
Power for this T-Con card is 12 volt
If the voltage is not present that may be responsible for this would see or if protection fuse is open
Well that might also be the would have now well there are many more things to review when we have
A fault like this if the protection fuse is in good condition and the other voltages of which
Emits that T-Con card towards the panel are present then we're going to have to doubt
Of the LVDS signal, or similarly doubt the chips COF on the panel but we
And those already engaged in repairing this kind of TVs then immediately
We see these breakdowns we know where and how to work but remember that my channel is coming
A lot of new people or colleagues who just started in the repair of this kind of TVs
And this knowledge still does not have them therefore we will proceed to connect the TV
To the electrical network and we will perform the corresponding checks in order to seek to solve the fault
On this screen
All right let's take negative ground chassis of any metal part of the screen
And we're going to take reading the input fuse how could you observe we have 12 volts power
And in the same way the voltage is entering correctly to the T-Con card Here we already ruled out The first part
We see the power supply voltage and we see that the protection fuse is in good condition
Now what we should do in the following if you look here carefully
You're going to find voltage cue points
In these cases we have the points marked as VGL, VGH voltage, VDD voltage
The three of these first ones I mentioned are the main voltage reference points
On the other hand we have the voltage VCC, and the voltage HVDD OK then these voltages need to be present
So that we can realize that the T-Con card is working
So that's what we're going to review mainly the first 3 voltage reference points you mention
are standard voltage reference points on all T-Con cards
Very well mainly let's check the voltage input to the integrated DC DC converter
There we see the 12 volts HVDD which would have to have 8 volts VCC of 1.8 VGL-5 Volts
And on this side we have the voltage point marked as VGH which would have to have 28 volts
y por este lado tenemos VDD de 16 voltios Pero cómo puedes darte cuenta no tenemos voltajes
If we touch these integrated in some cases we will find very hot which we would be indicating
That are damaged or are detecting a strong short circuit if any COF chip is damaged
Or if the interface card between the T-Con and the panel is damaged then the DC DC converter circuit goes into protection
To avoid major damage to this card then one of the techniques that we can apply here
is to disconnect these flexible cables one by one and how you can see this screen uses
Two flexible cables which is indicating part A and part B of the panel after that
We're going to check the voltage reference points here we have the point marked as VGL
How you can observe no voltage now let's review the next reference point VGH
Likewise there is no VDD voltage and how you can see the three main voltage points of which I have spoken
Because there is no presence of such voltage now we will disconnect this other and we will again check the voltage
These T-Con cards immediately receive the feeding voltage they would have to work
As you can see here now I have in the reference pin VGL-5 volts which is indicating to me that
This converter is working here I have VGH 28 volts which is indicating to me that the card
is already worked properly here I have the voltage marked as 16-volt VDD
Here we have the other reference point HVDD and how you can see here are the 8 volts
And we have the last point marked as VCC of 1.8 volts then I can realize that the T-Con card
is working properly then now we're going to connect again
The flexible cable that we had initially disconnected and we will again connect the TV to the mains
And again we will check the voltages if the voltages were lost we would know that part B
Of this Panel has problems we will review here again reference point VGL-5 Volts This correct
BGH 28 Volts VDD 16 Volts
HVDD 8 volts which is indicating that the card gets you working properly
In all the voltage emission sections to the panel now I'm going to raise the TV let's Watch
That the panel is representing us
Very well how can you see there you see that half of the panel now if you have voltage presence
Entonces señores Allá podemos darnos cuenta que la parte A de este panel está dañada
To solve this I would see I already taught some techniques in which it consists of eliminating some printed circuit tracks
Feeding that goes to the panel where the COF chips are located
But there are also other techniques to seek to solve this breakdown
For that then we're going to have to discover this card we'll have to remove this
Plastic protection to be able to access the card and review each of the components
That there are Okay let's work to this area let's look for which component is damaged
To seek to give solution very well gentlemen but we will do that in the video number 2
If you are interested in knowing more about the repair of this type of televisions stay pending
Of the following video in which we will seek to solve this breakdown
Very well gentlemen this is another video for the collection of electronic videos Núñez See you until the next tutorial
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