ViewSonic A91f+-1, Руководство по обслуживанию

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2.4 X-RAY radiation protection
﹒
FBT pin6 output one pulse to pass through D4407.ZD4403 .D4408 and C4420 integration DC voltage
﹐
and
through D4420.Q4404.IC402.pin 2
﹐
when anode voltage abnormal increase
﹐
FBT pin6 and IC402 pin2 voltage
to be increased
﹐
too
﹒
As IC402 pin2
≅
0.6V
﹐
IC402 X-RAY protection circuit immediately active
﹐
High voltage to shut-down
﹒
The X-RAY radiation protection circuit used in this monitor is a latching type the monitor will shown down
and continue until turn-off the monitor with power switch
﹒
3
﹒
Horizontal
﹒
3.1 Horizontal driver circuit
﹒
The output of IC401 pin26 H-Driver connect to Q403.Q404 H-Buffer transistor makes The Q403.Q404 push
pull output to Q406 H-driver, push H-output Q407 to reach secondary via induction of T4401
﹒
For T4401 is a
Transformer of reduced voltage and converted pole
﹐
Q407 will be turn off when Q406 is on
﹐
on the contrary
﹐
went Q406 is turn off and Q407 will be on
﹒
3.2 Horizontal output circuit
﹒
Horizontal output circuit is composed by Q407
（
Horizontal Transistor
）﹐
CRT YOKE.D406.C418 and C419.
H-output circuit
﹐
H-Driver circuit output via T4401to switch Q407 ON/OFF to output saw tooth wave and make
DY able to control the circuit scanning of elections in the CRT
﹒
L403
﹐
L404
﹐
C427
﹐
C432
﹐
C428 and C429 modify Horizontal linearity switching individually Dai RL401
﹐
Q415
﹐
Q411
﹒
3.3 EW-Pincushion and width control circuit
The parabolic waveform and DC voltage and generated from IC401 pin24 to Q405, R421, R422 to IC401
pin15
﹒
The parabolic decreased or increased for compensating the pincushion effect the DC voltage control the
H-width
﹒
3.4 High-voltage circuit
High-voltage circuit is composed by Q4401.T401 (FBT) and.C4406 .High-voltage output stage .
The IC 402 is PWM duty-cycle control.
1. Q4405 High voltage buffer stage.
2. Q4401 High voltage output stage.
3. Q4402 PWM control Driver stage.
4. Q4407.Q4408 .and Q4410 Brightness control circuit .
5. Q4406 D4426.R4429.R4430.VR4402 andC4427. ABL control circuit.
6. VR4401 High voltage control.
7. VR4402 ABL Lever control.
21
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nfidential - Do Not Copy A91f+-1