SECTION IV CRT DRIVE CIRCUIT
2. CIRCUIT OPERATION
For example, Green axis circuit is explained as follows.
(1) G signal which is output at pin 6 of AN5862K, is
supplied to the base of Q904, and is amplified in wide
band by Q903 and Q904. Then it is input to cathode of
CRT.
(2) The level of pin 7 of ICX001 TA1203AP becomes (L)
in RGB and (H) in TV. Utilizing this level change,
emitter bias level of Q904 is changed over RGB mode
and TV mode.
(3) The MUTE signal is generated at pin 9 of ICX001 in
POWER ON/OFF, CH selecting, MODE changing.
This signal turns Q903 to cut-off to prevent disorder of
picture from displayed on screen.
(4) Cut-off and Drive controls can be adjusted with R952
and R954.
1. OUTLINE
CRT Drive circuit is designed with its output load resistance
decreased, to obtain wide frequency band, and heat-sink of
output transistor is enlarged in size. Cut-off control and
Drive control of TV signal are adjusted with variable resistors
on CRT drive circuit, otherwise RGB signals are adjusted by
bias control and gain control of RGB AMP ICR03 M52327SP.
Fig. 1
R927
SERVICE
SWITCH
R922, R923, R924
+200V
L905
R921
R925
R926
L906
Q903
R915
R920
L904
+12V
QR05
RR26
RR25
QR04
DR08
C907
KG
Q904
R918
R952
R918
R954
C904
R914
D902
RR24
CR13
ICX001 TA1203AP
MUTE Pin9
C909
C910
R946
R945
R947
R943
R207
DEF Circuit
D904
D905
Q908
Q904
R961
R948
R949
-Y
R964
R944
Q907
R941
R942
+12V
ICR03
Pin6
ICX001 TA1203AP
TV/RGB
Pin7
R209
Q206
4-1
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