BLOCK DIAGRAM
Transcript of BLOCK DIAGRAM
BLOCK DIAGRAM
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PO
WE
R IN
PU
T10
0~24
0VA
C(5
0/60
Hz)
Line
Filt
er
Deg
auss
ing
Circ
uit
[ O
SD
Co
ntr
ol ]
SM
PS
TR
AN
S(T
901)
SM
PS
CO
NT
RO
L(I
C90
1)
DP
MC
ON
TR
OL
CIR
CU
IT
175V
75V
15V
-12V
6.3V
5V
TIL
TC
ontr
olC
ircui
t6.3V
15V
E2 P
RO
M(I
C40
2)
5V
OS
D IC
(IC
301)
H-S
ync
Sig
V-S
ync
Sig
I2C
DA
TA
(SD
A)
I2C
CLO
CK
(SC
L)
VID
EO
PR
E-A
MP
(IC
302)
Sig
nal
Cab
leR G B
VID
EO
MA
IN A
MP
(IC
303)
8V R
EG
.(I
C30
4)8V 12V
CU
T O
FF
CO
NT
RO
L
130V 8V
5V H/V
Syn
c P
roce
ssor
( IC
701
)
TD
A48
56V
-OU
T(I
C60
1)T
DA
4866
H-O
UT
(Q70
6)
H-L
inea
rity
Cor
rect
ion
DC
/DC
Con
vert
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X-R
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Pro
tect
ion
Circ
uit
FB
T(
T70
1 )
Dyn
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usC
ircui
t
Aut
oB
eam
Lim
it
Ver
tical
Bla
nkin
g,B
right
ness
Con
trol
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0V
40V
6.3V
D/D
Fee
d B
ack
30V
15V
MIC
OM
(IC
401)
SC
L / S
DA
H/V
Syn
c,P
WM
Con
trol
Sig
12
V
15V
175V
DY
CD
T
Hea
ter
( 6.
3V )
I2C
I2C
I2C
H/V
Syn
c
G1Screen
Dynamic FocusStatic Focus
H.V
R/G
/B
Bia
sR
/G/B
Con
tras
t
H-D
RV
B-D
RV
B+
15V
TILT COIL
DEGAUSSINGCOIL
I2C
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GE
FE
ED
BA
CK
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V P
OS
ITIO
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CA
LL
DESCRIPTION OF BLOCK DIAGRAM
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1. SMPS(Switching Mode Power Supply)When you turn on the power switch, the operatingprocedure is as follows:1) The AC line voltage is rectified by the bridge diodes
D901, D902, D903 and D904.2) The control IC(IC901) starts switching and generates
switching pulses in the primary turns of the SMPStransformer (T901).
3) The switching pulses of the primary turns are inducedthe secondary turns of the transformer by the turnratio. These pulses are rectified by each diode (D920,D922, D923, D924 and D926) .
4) Each rectified DC voltage (75V, 175V, 5V, 15V and6.3V) is supplied to the main circuit.
2. Over Voltage Protection CircuitWhen the input voltage of IC901 Vin(pin 4) is more than22.5V(typical), all the secondary voltages of the SMPStransformer (T901) down to low value.
3. Display Power Management Circuit1) Stand-by and Suspend mode.
When no input of horizontal or vertical sync, Q923and Q930, are turned on and Q920, Q926 are turnedoff. Then input power consumption is below 15 watts.
2) OFF modeWhen no input of horizontal and vertical sync, Q923,Q926, Q930 are turned off and Q920 is turned on.Then input power consumption is below 5 watts.
4. X-ray Protection CircuitWhen the high voltage reaches to 29kV in an abnormalcase, the high voltage detector circuit, R734, R717,R718, R719, R785, VR701, IC701 start operation toshut down high voltage circuit.
5. Microprocessor Control Circuit.The operating procedure is as follows : 1) Horizontal and Vertical sync signals are supplied to
the microprocessor(IC401).2) Microprocessor(IC401) discriminates the operating
mode from the sync polarity and resolution.3) After microprocessor reads these adjusted mode
data stored at EEPROM, it controls operating modedata through IIC.
4) Users can control screen condition by the OSD, SET,UP, DOWN, RIGHT and LEFT buttons.
6. D/D Convert Circuit.To obtain constant high voltage, this circuit suppliescontrolled DC voltage for FBT and horizontal deflectioncircuit according to the horizontal sync frequency.
7. Horizontal and Vertical Sync Processor Circuit.The horizontal and vertical sync processor IC(IC701)has a sync detector, a saw-tooth generator, and drivefunction. So output horizontal and vertical drive signalcontrol screen distortions.
8. Horizontal linearity Circuit.This circuit corrects the horizontal linearity for eachhorizontal sync frequency.
9. Horizontal drive and Output Circuit.This circuit is a horizontal deflection amplifier for rasterscan.
10. ABL Circuit.This circuit limits the beam-current for the reliability ofthe CDT.
11. Vertical Output Circuit.This circuit takes the vertical ramp wave from theTDA4856(IC701) and performs the vertical deflection bysupplying the saw-tooth wave current to the verticaldeflection yoke.
12. Blanking and Brightness Control Circuit.Blanking circuit eliminates the retrace line by supplyinga negative pulse wave to the G1 of the CDT.Brightness control circuit is used for control of thescreen brightness by changing the DC level of the G1.
13. Video Processor Circuit.Video processor circuit consists of the video driveoutput block. The video drive IC(IC302) receives thevideo signal from PC. The gain of each channel iscontrolled by the voltage of contrast pin. The cut-offcircuit compensate different voltage of each channelbetween the cathode and the G1 of the CDT.
14. OSD (On-Screen-Display) Circuit.This circuit displays on the screen information of themonitor's status.
WIRING DIAGRAM
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