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TC-L37DT30 Standby Power (2)
When the power button of the TV or remote control is pressed, The MPU (IC8000) of the A
board outputs the TV_SUB_ON command to turn on the transistors Q2001 and Q2002 which
provide STB5V to the photo-coupler located on the power supply board. The STB5V enters the
power supply board via pin 9 of connector P2. The TV_SUB_ON command is also connected
directly to the power supply to turn on a transistor that provides a ground connection to the
photo-coupler. When the photo-coupler turns on, the switched mode supply goes in operation to
create the +16V or and DC24V supplies.
On the A-Board, the +16V is regulated to numerous voltages to power the A-Board.
The DC24V is applied to the “Tcon/LED drive board” to power the circuit that controls the light
output of the backlight LEDs. However the backlight circuit is not yet tuned on because this is
only a self-check operation.
Caution: The A and P boards are to be exchanged only. The “Tcon/LED drive board” is part of
the LCD panel. If defective, the panel should be replaced.
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