This is the usual arrangement to lg Led tv at least untill 2013.
1=Start up rectifier stand by regulator 3,5v
2=Main board 3,5VST feed reset generator and microprocessor
At this point TV is in Stand-By state.
3=Ft IR/soft touch key to microprocessor.
4= microprocessor signal to relay then bridge start and feed 12/24 v regulators.Back light start.
5=Regulators feed audio amp and panel chip on main VCC 12v start on main.(PWR DET on)
6=T con start 12vLVDS panel receive voltages VCC VDD VGL P VDD VGL-I VGH.Also microprocessor signal VCC chip
7=Micro start SMPS inverter
8=P-DIMM global diming PWM-DIM sent to SMPS inverter, video processor stars from main and sent P-DIMM 1 to inverter, Lvds have video.
9=Main board sent signal to inverter SCLK MOSI CLK and local diming (Mixing local and global dimming) to feed the panel.
When the SMPS receives the DRV_ON command from the Main board (3.26V)
it turns on the on-board Inverter to start driving the LED backlights. The backlight brightness is controlled by the Main board
TUPICAL MICRO TURN ON COMMANDS
1=Reset 3.5V ST
2=key 1 key 2 variable
3=PWR ON 2.6V
4=PANEL VCC 12V
5=POWER DET Variable
6=Inverter on 3.3V
7=PWM-DIM1 (PWM Dimming) can vary according to incoming video IRE level Backlight setting
Range 0.37V to 3.3V.
8=SCLK/DIM0 VS 3.51V(DIM0 MOSI DATA 3.56V)
9=SBY 3.5v (to feed reset)
TESTING
To start up the SMPS brige PWR ON with STBY 3.5V Check that the power supplies are turned on
if no Backlights during this test put another jumper DVR ON with STBY and see if the DRV_ON line pulling up to at least 3V.
One LED can be tested with a Diode Check using a DVM. Forward biased,the LED should light.
Led drive dimming control 120Hz 12Vp-p on 2mSec time off. When DRV_ON command arrives on power Supply for the Backlights the voltage rise and fall quickly(example 45 to 65v and back)
To test Tcon jump 12v from SMPS to the Tcon fuse.Disconect the LVDS cables Jump VCC 3.3v to the LVDS(CN1) connector ground pin.Aply ac to power supply, patterns of White, Red, Blue, Green
should appear on the screen.Voltages can be read at the ribbon connector or at test locations on the board (typical 16.74V, 3.3V, -5V and 28V)
AUDIO section
• 3.3V_AU_AVDD (Made from 3.3V_Normal).
• 3.3V_DVDD (Made from 3.3V_Normal).
• 1.8V made from (From 3.3V_Normal )
• 24V (Direct from SMPS)
Video Processor 3.3V_ST (Direct from SMPS)
5V USB (Made from 12V)
3.3V_Normal (Made from 12V)
3.3V_HDMI ((From 3.3V_Normal)
3.3V_ST (Direct from SMPS)
5V_Normal (Made from 12V)
TUNER
5V_TU (Made from 5V_Normal)
3.3V_TU (Made from 3.3V_Normal)
1.26V (Made from 3.3V TU)
1=Start up rectifier stand by regulator 3,5v
2=Main board 3,5VST feed reset generator and microprocessor
At this point TV is in Stand-By state.
3=Ft IR/soft touch key to microprocessor.
4= microprocessor signal to relay then bridge start and feed 12/24 v regulators.Back light start.
5=Regulators feed audio amp and panel chip on main VCC 12v start on main.(PWR DET on)
6=T con start 12vLVDS panel receive voltages VCC VDD VGL P VDD VGL-I VGH.Also microprocessor signal VCC chip
7=Micro start SMPS inverter
8=P-DIMM global diming PWM-DIM sent to SMPS inverter, video processor stars from main and sent P-DIMM 1 to inverter, Lvds have video.
9=Main board sent signal to inverter SCLK MOSI CLK and local diming (Mixing local and global dimming) to feed the panel.
When the SMPS receives the DRV_ON command from the Main board (3.26V)
it turns on the on-board Inverter to start driving the LED backlights. The backlight brightness is controlled by the Main board
TUPICAL MICRO TURN ON COMMANDS
1=Reset 3.5V ST
2=key 1 key 2 variable
3=PWR ON 2.6V
4=PANEL VCC 12V
5=POWER DET Variable
6=Inverter on 3.3V
7=PWM-DIM1 (PWM Dimming) can vary according to incoming video IRE level Backlight setting
Range 0.37V to 3.3V.
8=SCLK/DIM0 VS 3.51V(DIM0 MOSI DATA 3.56V)
9=SBY 3.5v (to feed reset)
TESTING
To start up the SMPS brige PWR ON with STBY 3.5V Check that the power supplies are turned on
if no Backlights during this test put another jumper DVR ON with STBY and see if the DRV_ON line pulling up to at least 3V.
One LED can be tested with a Diode Check using a DVM. Forward biased,the LED should light.
Led drive dimming control 120Hz 12Vp-p on 2mSec time off. When DRV_ON command arrives on power Supply for the Backlights the voltage rise and fall quickly(example 45 to 65v and back)
To test Tcon jump 12v from SMPS to the Tcon fuse.Disconect the LVDS cables Jump VCC 3.3v to the LVDS(CN1) connector ground pin.Aply ac to power supply, patterns of White, Red, Blue, Green
should appear on the screen.Voltages can be read at the ribbon connector or at test locations on the board (typical 16.74V, 3.3V, -5V and 28V)
AUDIO section
• 3.3V_AU_AVDD (Made from 3.3V_Normal).
• 3.3V_DVDD (Made from 3.3V_Normal).
• 1.8V made from (From 3.3V_Normal )
• 24V (Direct from SMPS)
Video Processor 3.3V_ST (Direct from SMPS)
5V USB (Made from 12V)
3.3V_Normal (Made from 12V)
3.3V_HDMI ((From 3.3V_Normal)
3.3V_ST (Direct from SMPS)
5V_Normal (Made from 12V)
TUNER
5V_TU (Made from 5V_Normal)
3.3V_TU (Made from 3.3V_Normal)
1.26V (Made from 3.3V TU)