Power Supply - LG 55LW5600 Troubleshooting Manual

POWER SUPPLY SECTION
This switch mode power supply develops Stand By 3.5V at all times when AC is applied. At
power on, it develops 12V and 24V for the Main board.
It develops 63V for the LED Backlights. It d l 63V f
This power supply draws less than 1 watt during stand by mode. The fuse F101 reads approximately
57V and F501 reads 154V during this time (from hot ground) . The transformer T501 delivers an AC
signal which is rectified and filtered by D201, D202, C201 and C202 which develops a Stand-By
voltage of 3.55V which is used by the SMPS Controller circuit and is also sent to the Main Board. It voltage of 3 55V which is used by the SMPS Controller circuit and is also sent to the Main Board It
is output P201 pins 9~12 and sent to the P502 on the Main Board.
When the controller chip on the back side of the SMPS receives the PWR-ON command 3.4V via
P201 Pin 1, it turns on the Relay RL101 which supplies AC to the bridge rectifier BD101. The
primary section (Power Factor Controller circuit) increases its current supplying ability.
Both Primary fuses F101 and F501 now reads between 395V~397V (from hot ground).
D253 receiving switching pulses from L601 and filtered by C256 and C257, develops the 63V for the
LED backlights.
When the SMPS receives the DRV_ON command from the Main board via P201 Pin 18 (3.24V) it
turns on the on-board Inverter to start driving the LED backlights. The backlight brightness is
controlled by the Main board via PWM Pin 22 and Local Dimming signals via P832.
P201 Connector: (To Main Board) (
3.5V_ST (3.55V) output P201 pins 9~12
12V output P201 pins 17, 19 and 21
24V output P201 pins 2, 3 and 4.
Turn on commands.
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) P202 Connector: (To Panel LEDs) (
63V output P202 pins 1 and 12.
P203 Connector: (To Panel LEDs)
63V output P203 pins 1 and 13.
P832 Connector: (To the Main Board)
This connector receives the Local Dimming signals.
July 201 1 LCD TV
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55LW56000