NEC PlasmaSync 50MP1 User Manual page 111

(2) Auto-picture function
In IC7501, the screen position data are computed according to the input video signal when the auto-picture
feature is turned ON for the RGB input. During the entry of RGB3 input, the screen position data are
computed based on the DE signal sent from IC7002. The microcomputer picks up the screen position data
from IC7501, and sets up the screen position in IC7501 and IC8502 based on the obtained data.
(3) Last memory function
The input mode, power ON/OFF status, setting values of various user controls, factory servicing values,
and such data are stored in an external EEPROM (IC9504). During the entry of VIDEO input, however, data
of color, tint, and UCOL are stored in IC1011 of the VIDEO PWB. In the SECAM mode, data of R-Y, B-Y, and
BELL are also stored in this IC1011.
(4) Error detector block
The microcomputer is in charge of fan stoppage, plasma display module alarming, and temperature sensor
detection.
1
Detection of fan stop
Two fans are loaded on the set main body. If a stop signal ([H]) from either fan is entered in IC9805 and
even a single fan unit stops as a result, the "L" signal is sent to the microcomputer IC9501. When either
fan stops, the relevant LED blinks in green and the power supply assumes a standby condition. The
function of fan stop detection is disabled when Pin 2 and Pin 3 of S9802 are short-circuited with a
jumper wire or the like.
2
Panel crack detection
If there is any abnormality in the plasma display module (signal system), an alarm signal is sent from
Pin 37 of the "AD" connector to Pin 100 of the microcomputer. When this terminal is at the "L" level, the
LEDs repeat reciprocal lighting in red and green, in order to indicate a condition of power supply in
standby mode. To reset alarming, the input changeover key is kept pressed at the set main body and
the mains POWER of the main body is turned "ON." In this case, it is necessary to keep pressing the
input changeover key at the main unit for more than 2 seconds.
3
Temperature error detection
When the temperature sensor of the power unit senses any abnormality or when Pin 8 of the "PN"
connector is turned to be at the "L" level, the LED flashes in red and a condition of power standby is
assumed.
(5) Temperature sensor block
The information about the internal temperature in the set is transmitted from the temperature sensor boards
(SEND PWB, SENT PWB) to the microcomputer via the I2C bus SCL5 and SDA5 of the T1 connector.
Based on this information, the microcomputer controls the output voltage of the regulator IC9802 and
IC9803 via IC9805. In this fashion, fan revolutions are increased and decreased.
(6) Remote control block
This system is applicable to remote controls. An infrared remote control light receiver block RV2101 is
mounted on the LED PWB. Its signal input is entered in IC9808 through the "LD" connector. The 232C PWB
is provided with the wired remote control input terminals and an input from the "RA" connector is entered in
IC9808. In IC9808, a signal of infrared remote control is generally selected and its input is fed to Pin 7 of the
microcomputer IC9501. When a wired remote control is connected, the potential at Pin 2 of IC9808 is
turned at the "L" level and the signal of wired remote control is selected so that its input is entered in the
microcomputer.
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