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CRT DRIVE CIRCUIT
R901
33
RgO?
m
Il'2.W
430
p~~?: 6~: CD
.
' M -----IP>---' V VV-
. POOe:
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1
R90e
lRF-IOI9
430
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I II
I
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I
P9~2 T~UJ
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~·-r----r-1-~-92---~Z-90-1f;=;====~
PWB-169:
R902
L902
200V
IPf
GIG-
POGZ
®
1 .
3.3
TRF - 1019
": 20,)V
..
. ll2W
-
R909
430
. P903 T I - l
J#v
PWB- 1697
.
R903
PIZZ
® .
33
.
1/2W
(,912
1
103K
!KV
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r----~l~-v~--~-----4------~
eg09
RI09~4
Z9~5
1021<
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I P
r
FROM
R913
SUB 8R1, .....-.:
SOPT K !LLER
CIRCUIT
IKV
'2.o')v
':-
3.47 SPOT KILLER CIRCUIT
CRT,
t:901
r ·
IO,3K
IKV
P9050-
R905
1M
! 12W
(Refer to circuit diagram Fig-47)
The DYNAMIC FOCUS VOLTAGE is also fed to the
The spot killer circuit is introduced. In order to
CRT via the dynamic focus circuit.
eliminate the SPOT damage on the screen of the CRT
while power is on or off.
SPOT KILLER CIRCUIT
The circuit supplied of -189V is provided by the zener
diode chain 0903 to 0908.
When power is on, +24V and -189V will charge C911
via 0902.
Totally will have -213V voltage charge on C911. At
this moment 0901 is off.
When power is off, the positive end of C911 is
grounded, 0901 is on, -213V will fed to G1 of CRT
via 0901 to achieve the SPOT KILLER purpose.
Potentiometer R907 is used as SUB. BRIGHT for the
monitor.
The BLANKING signal is fed to G1 via pin 3 of P904
and C904.
TEST
The HEATER VOLTAGE +6V is fed to the CRT via
CONDITION
pins 1, 3 of P907.
Fh=31KHz
The HIGH VOLTAGE +26KV is fed to the anode of the
=
3-38
=
TEST
POINT
N1
Fig-47
TEST POINT NAME
BLANKING VOLTAGE
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