8-54
1-B) SENSOR OF TEMPERATURE CIRCUIT
Temperature Sensor (IC151) is used in this circuit.(on CONTROL PWB)
When the surrounding temperature of the unit change, the voltage of IC151 out put pin (CNCL 16pin on
VIDEO PWB) varies.
This voltage is fed to the A/D converter in IC801 (pin50)
0
Temperature (
°
C)
20
40
60
80
100
200
400
600
800
1000
CN
CL
pin
1
6 Vo
lt
ag
e
(
m
V)
(Fig.10.2) The example of Temperature sensor (IC4H1) voltage
1-C) SENSOR OF CRT BEAM CURRENT CIRCUIT
Change of purity is caused by warm up after power on and changing of CRT beam current.
Correction voltage is generated by charging C4P1. This voltage can detect both warm up and changing of
CRT beam current. Warm up is detected by C4P1 charging time, changing of CRT beam current is detected
by changing of ABL voltage. Correction voltage is input to IC801 pin 51. IC801 calculates four corner purity
correction. Q4P2 is switch in PMS and power off. Q4P4 is buffer of correction voltage.
+12V
R4P5
IC801
CPU
MD4P2
51
R4P7
ABL Voltage
Q4P4
D4P1
+12V
S5V
+12V
Q4P2
R4P4
C4P1
R4PH
R4PF
MD4P1
R4P9
R4P8
R4P1
R4PA
R4PE
Q4P3
Q4P1
(Fig.10.3) Sensor of CRT beam current circuit