The Pictures on the panel screen are sometimes good, sometimes flawed …… .. alternating periodically.
Defects can have many kinds of symptoms: maybe shakes, maybe lines, maybe doubles etc.
This can happen to LG using the GIP (Gate In Panel) panel.
Which is indicated by the presence of VGH_ODD and VGH_EVEN voltages from the Tcon that enter the panel (image above).
If the voltage at both TP is measured, it will keep changing periodically ...
Sometimes the positive voltage is VGH / sometimes the negative voltage is VGL.
The voltages VGH_Even and VGH_Odd are always opposite. This means that if VGH_even is positive, then VGH_Odd will be negative.
The same symptoms can also be found on AUO panel models. Where there is also found a TP whose voltage is always changing positive and negative.
AUO panel pictures sometimes good, sometimes double or blurry
Panel 32 made by AUO….
Unclear panel type …….
Picture problem changes periodically .... sometimes good sometimes double / blurred
Near the COF column there are test points HC1, HC2, LC1, LC2
................. can be solved ……. Because there are similar problems with LG using Vgh_O and Vgh_E
Check the voltage at the LC2 test point changing periodically ...
Sometimes the same as Vgh, sometimes negative with Vgl …….
When the voltage is equal to Vgh the picture is fine.
When the voltage is equal to Vgl image problem...
Check the voltage on the test point LC1 also changes periodically the same as above ... the difference is only when the image is good the voltage is the same as Vgl.
Check with an ohm meter ..... LC1, LC2 voltage supply from IC Level Shifter 17328.
Cut the connection from LC1, LC2 to the IC Level Shifter by removing the R jumper.
Then dial directly:
LC2 fixed to Vgh voltage.
LC1 fixed direct dial to Vgl. .
This is not a T.con malfunction, but a glass panel malfunction similar to the Samsung image shake / double panel damage.
The solutions to the above problems are:
The first step.
Observe the picture …… .. while measuring the VGH_odd voltage (or it could be VGH_Even)
Observe carefully the voltage when the image position is good, what is the VGH_odd voltage.
For example, a good image when the VGH_Odd voltage is positive.
Second step.
Cut the VGH_Odd and VGH_Even paths entering the panel from the source.
This voltage comes from an IC called LEVEL SHIFTER.
Third step.
After the line is cut.
Because the picture is good when the position of the VGH_Odd voltage is positive.
Then the jumper goes directly to VGH_Odd to VGH
And the reverse is the VGH-Even to VGL jumper.
Note:
If the image is good when VGH_Odd is negative.
Then VGH_Odd is jumped to VGL