NEC PlasmaSync PX-42M2A, Руководство по обслуживанию

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CIRCUIT DESCRIPTION
V. Power Block Operation
1. Power unit
When AC power is obtained from AC inlet, the POWER unit begins to supply Power M +14V from Pin 1 of the
“PM” connector for the microcomputer.
When POWER signal “H” input is entered from Pin 2 of the “PM” connector, RL1 is turned ON and low-voltage
power (D+5V, A+7V, A+14V, S+13V, F+12V) is supplied to each signal circuit.
When the POSAVE signal “H” input is fed from Pin 3 of the “PM” connector, an output of high-voltage power (D-
180V, D+80V) is supplied to the plasma display module.
The POMUTE signal is the first such output signal (L) when the AC power plug is pulled out. This output is
applied from Pin 4 of the “PM” connector to the ANALOG PWB.
When the internal temperature of the power unit attains about 100
°
C, the T-ALM (DETTO) signal is used to
output the “L” signal from Pin 12 of the “PM” connector to the ANALOG PWB.
If the fan fails in the power unit, the DETVO signal is used to output the “H” signal from Pin 13 of the “PM”
connector to the ANALOG PWB.
When the LVP signal (L), output from the MODULE, is fed from Pin 7 of the PH connector, RL1 is turned OFF
to stop the supply of power other than the power (M+14V) for the microcomputer.
2. Power block for the microcomputer
When the power cord is connected to a wall outlet, the power block for the microcomputer generates a power
output of M+14V at Pin 1 of the “PM” connector for the ANALOG PWB, and supplies it to the REG IC6805.
When the main power switch SW2001 is turned ON, an “H” signal is supplied to Pin 4 of IC6805, and this
IC6805 begins to feed M+5V to the microcomputer IC6800.
3. Power for ANALOG PWB
The power input of D+5V obtained from Pins 5 to 7 of the “PM” connector is supplied to the AD converter and
the digital signal processor circuit. Another power of M+3.3V is also supplied to IC6551 (VDD3) through the
REG IC6073.
The power input of M+14V obtained from Pin 1 of the “PM” connector is used to feed power to the plag and play
(P&P) circuit; such as M+12V through the REG IC6003 and M+5V through the REG IC6805.
The power input of A+14V obtained from Pins 1 and 2 of the “PN” connector is regulated to A+12V through the
REG IC6000 and IC6300. The power input of A+7V obtained from Pins 5 and 6 of the “PM” connector is
regulated to A+5V through the REG IC6001 and IC6300. These power supplies are fed to the ANALOG signal
processor circuit and the A/D circuit. The power of A+7V is regulated to +4V through the REG IC6072 and
supplied to the clock signal generator.
4. Power for VIDEO PWB
The power input of A+14V obtained from Pin 1 of the “PV” connector is regulated to A+9V through the REG
IC5001, IC5002, and IC9006. The power input of A+7V obtained from Pin 3 of the “PV” connector is regulated
to A+5V through the REG IC5003. These power supplies are fed to the VIDEO signal processor circuit.