NEC PlasmaSync 50MP1, Руководство пользователя

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1
CIRCUIT DESCRIPTION
(Note) In regard to the contents of the text, please refer also to the relevant circuit dia-
grams.
■
Power unit block [Including the power-related
µ
-COM (microcomputer) operation]
• When a commercial power input is fed from an AC inlet, the power unit begins to generate an output of M+7V
for the
µ
-COM system. M+7V is supplied to IC9502 from Pin
1
of the PM connector. When the main POWER
SW (S2601) is turned ON, M+5V is supplied to the
µ
-COM (IC9501). With the supply of M+5V, the
µ
-COM
supplies a “POWER” signal to the power unit to actuate it.
• When the [H] input of the “POWER” signal is fed from Pin
3
of the PM connector, RL1 is turned ON to
generate power outputs for the signal system (D+5V, D+3.3, A+14V, A+5V, S+13V, S-13V). These power
outputs are fed to the respective signaling circuits. After each signaling power supply has been fed (for
200msec or more), the power outputs (D+170V, D+70V) are fed to the HV system, and extended further to
the PDP module.
• When the temperature in the power unit attains about 100
°
C, the T-ALM2 signal begins to feed an “L” signal
to the MAIN PWB (
µ
-COM) from Pin
8
of the PN connector. The
µ
-COM turns the “POWER” signal at the “L”
level to turn off the power supply. In this state, the LED flashes in red. (T-ALM1 is not used.)
• When an LVP signal at the “L” level from the PDP module is entered in Pin 37 (MAIN PWB) of the AD
connector and in Pin
1
(power unit) of the PD connector, the
µ
-COM turns the “POWER” signal at the “L”
level and makes the LED “flash in red and green reciprocally.” The power unit turns off all the power supplies
other than the M+7V system.
• The POMUTE signal is used to detect AC OFF first of all and supplies an “L” output to Pin
4
of the PM
connector. This signal is fed to Pin 93 of the
µ
-COM and Pin
4
of the AE connector (AUDIO unit). This circuit
is used to perceive the occurrence of commercial power OFF due to a service interruption or a certain cause
(prevention of misoperation). It is also used for MUTE.