LG 37LH55 _ LCD TV _ T'CON BOARD CHECK AND REMOVAL

T-CON [LCD CONTROLLER BOARD]

     The TCon IC UC1 receives from the Main Board LVDS at CN1 and CN2. This is a duel 24 Bit LVDS Video Signal which it processes into TFT Drive Signals which are delivered through connectors CN4 and CN5 to the LCD TFT Panel.

     12V is supplied to the TCon Board on connector CN1 from the Main Board easily measured at fuse F1, (3A and 125V). There is a DC to DC converter that creates; (16.3V Measured at VDD). (26.2V Measured at D5 cathode). (3.3V Measured at VCC). (- 7.47V Measured at D6 bottom left leg).

     These Voltages can also be measured at the ribbon connectors delivering signals to the TFT panel (CN4 26.2V pin 8, -7.4V pin 11, 3.3V pins 53, 54 and 16.3V pins 56, 57). (CN5 26.2V pin 7, -7.4V pin 6, 3.3V pins 53, 54 and 16.3V pins 56, 57).

     Remove 2 screws in the T-Con shield [These two screws have to be replaced in the board if the TV is to be run without the T-Con shield in place]

     There is a chocolate heat transfer material pieces on the back of the T-Con heat sink.  They dissipate heat from the UC-1 and US-3 ICs.  Be sure to return these pieces when re-installing the heat sink.

T-Con: part number- EAT60664401.

Disconnect CN1, CN2, CN4 & CN5.  Be sure to place the two seating screws as shown here. 

     To remove the flex cables to the TFT panel, CN1 or CN5:  Place a soft thin object like a fingernail underneath the back locking tab, and gently pull upwards.  Flip the lock up and back from the flex cable.  Then the cable can be easily removed.

To remove the LVDS cable CN1:  Press in on the two tabs and slowly rock the cable out of the connector.

Pull out the cable from CN3 [P-DIM]

T'CON PWB checks

Check the regulator US2 for correct voltage.  

T'CON Panel voltage development check:  The development for the voltages on the CN4 & CN5 connectors are shown from the interconnect diagram.  They are outlined in rounded cornered boxes.