Originally Posted by Extreme_Boky
The fact that picture intermittently returns to normal tells me that the problem is most likely related to TAB; not the T-CON board, but it is difficult to say. The TAB in the flat panel display industry is used to mount driver chips between the glass of the display and the input circuitry behind the display – the contact resistance can build-up with time and significantly effect conductivity, in particular with the change in TV, as well as ambient temperature.
Allow me to correctly explain what tab bonding is.
The gate and source drive components to control the liquid crystals are mounted on flexible circuit boards (known as flexible printed circuits, or FPC, for short). These components are “bonded” to the FPC. This is a solderless method.
The FPC is then “bonded’ to the LCD panel glass with a special glue that contains tiny metal balls. These metal balls provide the conduction from the pads on the FPC to the pads on the panel glass. The balls are small enough so that if any find their way between the pads they will not short circuit adjacent pads.
If one of the components on the FPC fails, or the bond of one or more of the FPC pads breaks from the LCD glass, the entire FPC must be replaced. This is known as “re-tabbing” the panel.
A very expensive machine is required to heat the area where the FPC bonds to the panel glass. This softens the glue so the FPC can be removed. The pads on the glass are cleaned, new glue is applied, a new FPC is positioned, and the area where the pads are located is re-heated to activate the new glue.
The FPC assembly looks like a tab you would find on a filing cabinet folder indexing tab and that is where the term came from. Any component failure on the FPC or loss of bonding between the FPC pads and the panel requires a tab replacement and re-bonding.
Newer panel designs have eliminated the tab bonding requirements on the gate driver side of the panel (that’s the left side) by incorporating the drive components into the LCD glass. The column drivers (source) are still bonded to a FPC coming from the TCON board.
If the problem you have shared with us was caused by a tab bonding issue it would require the failure of one-third of all the tab bonds along the top of your LCD panel. That does not happen unless the panel has suffered severe physical damage. You have a TCON problem.