Standby Operation - Panasonic TH-42PX80U Service Manual

Standby Operation

When the TV is plugged in:
AC is applied to the standby circuit in the power supply to produce STB12V and STB5V.
The STB12V is routed thru the SS board and it's returned back to the P board to turn on a
switching circuit that outputs the STB5V. If the STB5V is missing, the TV is dead (No power)
The STB5V is output from the P board at pin 5 of connector P7 and it is applied to pin 5 of
connector A7 on the A board.
The STB5V is applied to a 3.3V regulator to power the Main CPU (IC1100) on the A board.
When the Main CPU (IC1100) receives 3.3V, it outputs a temporary 2.7V/3.2V command that
is provided to pin 6 of connector P7 on the P board. The function of this command is to turn on
the circuit that generates the "F+15V" in the P board.
The P board outputs the F+15V to pins 7, 8, and 9 of connector A7 in the A board. This voltage
is applied to a regulator circuit that generates: SUB9V, SUB5V, and SUB3.V.
If any of these voltages (F+15V, SUB9V, SUB5V, and SUB3.3V) are missing, the TV shuts
down and the power LED blinks 10 times.
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