Saturday, November 07, 2015

LCD TV T-CON BOARD TROUBLESHOOTING - NO VIDEO – VERTICAL LINES – VERTICAL BARS – WHITE SCREENS – HALF OF THE SCREEN BLACK – HALF OF THE SCREEN LINE – BLACK PATCHES ON LCD SCREEN


LCD TV T-CON BOARD TROUBLESHOOTING 

SYMPTOM  

NO VIDEOVERTICAL LINESVERTICAL THICK BARS – SCREEN IS WHITE – HALF OF THE SCREEN BLACKHALF OF THE SCREEN HAS LINEBLACK PATCHES ON LCD SCREEN 

Video Process defect


Video signals received by the video process circuits are handled on a frame-by-frame basis. It I almost impossible for the video process circuits to cause a symptom on a specific area of the screen. Failures on the video process board usually presents themselves as distortions, color level shifts, video level shifts or noise that affects the entire picture. The TCON can develop symptoms that seem to be video process related but the video process circuits will not provide symptoms that would be mistaken for a failed TCON circuit.

LVDS cable defect

Although problems with the LVDS cable or connectors can cause symptoms that resemble TCON failures, they usually tends to be intermittent and wiggling of the connectors will likely cause a change in the symptom on the screen.



LCD Panel defect


At times, symptoms of a defective panel may be mistakenly identified as a TCON failure. Beside a broken LCD glass, most panel symptom would appear in a particular section of the screen. The TCON provides pixel data to groups of row and column drive ICs located on the upper and side edges of the panel. It is improbable that several of these ICs would fail at the same time. Therefore many columns or rows of pixels that are on or off point to a defective TCON. A single row of On or Off pixels cannot be attributed to the TCON. The TCON simply cannot cut out a single line of information

TCON defect



A failed TCON circuit can produce a symptom of no video or lines and patterns that usually occupy a sizeable portion of the screen. A “no video” condition caused by the TCON is a bit harder to determine since there are no indications on the screen to analyze.
TCON defect




A failed TCON circuit can produce a symptom of no video or lines and patterns that usually occupy a sizeable portion of the screen. A “no video” condition caused by the TCON is a bit harder to determine since there are no indications on the screen to analyze.

Troubleshooting a dead TCON board

When the TCON board completely fails, data communication data between IC and the TCON IC will come to an end. The television will shut down and the power LED will blink , indicating the failure of the TCON. When there is no error code, the usual approach is for the technician to replace the A-board. Once it is determined that the A board is not the fix, one can conclude with a degree of certainty that the problem is the TCON board.

Avoiding wrong board replacement

One way to determine the location of the fault is to loosen the LVDS connector at the TCON board while the unit is turned on. Unlock the connector and gently rock the cable in and out of the socket while observing the screen for any sign of noise. The response may be gentle white flashes, intermittent colored lines, or a screen full of random patterns. A TCON board that has completely failed will not generate any type of symptom on the screen. Another method to rapidly diagnose the TCON is to apply heat and/or cool with hot air devices or circuit coolant and watch for random noise to appear on the screen.