Samsung 32 and 40 inch LCD TVs – T’Con board problems – No display, Distorted picture, vertical lines or bars...........

Samsung T'Con board

 What is the T-CON Function? The T-CON (TFT Controller) is responsible for; 1. Driving the TFT panel. This is usually accomplished by two LVDS type cables between the T-CON and the th Panel. P l The Th panel l cell ll structure t t i is broken b k into i t Vertical V ti l columns l and d H Horizontal i t l rows. • Horizontal Resolution: On a panel with a resolution of 1920 X 1080 we must have 1920 X 3 columns, because a pixel is comprised on a Red, Green and Blue cell. So there will be 5760 individual cells in rows across the screen. To turn these cells on and off, the panel will use vertical address lines or electrodes driven by y a small board located inside the panel. p In this way y we can turn the colors on and off accordingly to recreate the correct colors required to recreate the image. • Vertical Resolution: On a panel with a resolution of 1920 X 1080 there will be 1080 horizontal rows of cells running across the panel. These rows are being driven by a small board inside the panel. By 2.addressing a particular cell via the vertical columns and turning on a row of cells, only the cells being address by the vertical electrodes will be activated. activated The number of horizontal rows determine the panels Vertical resolution. TFT: Each cell has is driven by a thin film transistor called (TFT) and a capacitor. When that cells is addressed (turned on) the capacitor will charge and will remain charged until the next refresh cycle. Generally speaking, when the cell has no power applied, it blocks the light from passing through, when it turns on, dependant upon how long it is on, allows more or less light to pass. In this way we can control the brightness level being output by that cell. Panel Voltages: The T-CON is responsible for developing panel voltages. These voltage will vary dependant upon the type of panel utilized. utilized We generally state there will be 4 voltages that are always being delivered to the panel, -5V, 3.3V, 16V and 26V. However, there may be more according to the type of panel being used. Backlights: Since the Liquid crystal panel does not generate any light of its own, there must be a light source behind the panel. This light source is called the “Backlights” called B\L here after. The B\L can be either florescent (EEFL or CCFL) or they can be LED. The T-CON is not responsible for turning on the B\L.


  T-CON Shield Purpose and Key PointThe T-CON shield may serve two functions. 1) They prevent RF radiation, either in or out. 2) They Th work k as a h heat t di dissipation i ti shield. hi ld Here are some key points to remember when removing the shield; o Many M of f th the shields hi ld h have a piece i of f material t i l that is used to transfer heat from a component on the board to the shield. This material is called “Chocolate”. Look for it when removing the shield. Make sure to return it to the correct location when replacing the shield. In the example on the right, the two pieces of chocolate are protecting the DC-to-DC converter coils in the lower right hand corner.

Understanding the LVDS Cable.

The LVDS (Low Voltage Differential Signal) Cable in a LCD TV is responsible for two primary jobs. 1. VIDEO and TIMING SIGNALS: To deliver video signals g that have been p processed into a positive and a negative going pair of signals. These pair of signals are sent is groups which equal the resolution characteristics of the panel. As an example if the panel is a HD panel, the differential pair will be 10 lines carrying positive and negative going video data. And there will be two line carrying positive and negative going clock signals. If the panel is a full HD panel, it will have double the amount of lines lines. The positive going signals will be designated on the schematic with the suffix of (P or +) and the negative going lines will be designated as (N or -). If you take one pare of video signals and look at them on a scope, they will be and exact mirror of each other. One going positive and one going negative. By using a differential pair, the circuitry can isolate and remove the noise on the line by addition and it can extract the actual signal by subtraction which will double the signal level. 2. T-CON VOLTAGE: The T-CON board needs voltage to operate, the LVDS cable will deliver the T-CON’s operational voltage. If the th LVDS cable bl i is suspected t d of fh having i a problem, bl most t often ft i is can b be seen visually. i ll L Look k for f the th cable being bent which cause the internal paths to be broken. The cable can be cut, or cracked or physically damaged in some way. The other problem that the LVDS cable can have is the continuity contacts that are on the side that goes into the connector can separate from the cable itself. This can only y be seen by y unlocking g the cable connector and removing g the cable. Then flipping pp g the cable over so the contacts points can be seen. See if they are separated from the cable. They could be curled up or even bent over and pressed onto another line causing a short. One other thing to look for is the cable being incorrectly inserted into the connector, (improperly seated). When the LVDS cable is causing a problem, the symptom can be many. Lines in the picture, portions blocked bl k d out, t every other th li line missing, i i noise i patters tt on the th screen, missing i i 12V t to the th T-CON T CON causing i a black or no picture symptom, etc... It can even shut the TV down if the 12V is shorted.

 Samsung T’con Board: 320WTLF3C2LV0.3

LCD Panel: 32 inches 
Vcc input= 5V
* IC12= 7585A power management IC. If this IC fails the TV will have No Display.
* IC18= EEPROM memory IC. If this IC fails, the TV will have No Display or White Screen.
* U1= TFP7517PNP. If this IC fails, the TV will have No Display or Display Abnormal problem.
* U1= EM638325TS-7G SDRAM memory IC. If this IC fails, TV will have No Display or Display Distortion

Samsung T,con Board: 400W2C4LTV0.1

LCD Panel: 40 inches

Vcc input= 5V

* OP3 = 54200CRZ & another one if this IC fail, one of the half (left or right side) will No Display or Display Abnormal.

* ICG1= 5327CRZ. If this IC fails, the TV will have No Display.

* ICD3= 2700NT power management IC. If this IC fails, the TV will have No Display.

* ICt1= LRX4222 IC. If this IC fails, the TV will have No Display or Display Distortion problem.

* ICD1 is a SDRAM memory IC. If this IC fails, the TV will have No Display or Display Distortion problem.

Samsung T’con Board: 400W2C4LV1.5

LCD Panel: 40 inches
Vcc input= 5V

IC320= EL7585AIL power management IC. If this IC fails TV will have No Display.
2) ICT1= LRX4222T3. If this IC fails, the TV will have No Display or Full Screen of Vertical Lines/Bars.
3) ICD1 is a SDRAM memory IC. If this IC fails, the TV will have No Display or Display Distortion problem.
4) IC322= 24006IRZ. If this IC fails, the TV will have No Display.