Daewoo 531B, 532B Service Manual

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D AEW OO ELECTR ONICS CO., LTD.
Service Manual
XGA COLOR MONITOR
Model : 531B
532B
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1
6
15
10
Page 8
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OSD OFF
MENU
MENU
MENU
MENU
DEGAUSS
UT L TY
EX T
UT L TY
MENU
MENU
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Page 11
OSD OFF
MENU
MENU
MENU
MENU
MENU
MENU
UT L TY
EX T
UT L TY DEGAUSS
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Change the Contrast & Brightness control value to maximum
No Raster
Refer to No Raster
Check the peripheral circuit of CRT
Check the video output circuit and its ambient circuit
Trouble in 12V line of the Main PWB
Check the clamping pulse circuit
Check the signal cable
No Character
Is whole
screen bright?
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
Yes
Yes
Rk, Gk, Bk
About 30~35Vpp
No
No
Is CRT
Cathode (Rk, Gk, Bk)
signal level
normal?
Is the
output signal of the
(pin 14, 16, 18) pre-amp
IC801, normal?
Is blanking
pulse (pin 20 of IC801)
normal?
Is 12V line
normal?
Is input signal
normal?
Trouble in IC801 and
its ambient circuit
5Vp-p
Are the Contrast &
Brightness Controls in
OSD menu
maximum?
Page 17
Trouble in power supply circuit
Trouble in power supply circuit
Trouble in G1 line
Trouble in FBT or its pin4 ambient circuit
High Voltage trouble in FBT
Trouble in 100Vdc line of power supply unit
Refer to trouble in P.S.U
Refer to trouble in power supply unit.
Is CRT
heater red-hot?
No
Yes
No
No
No
No
Yes
No
Yes
Yes
Yes
Yes
No
Is Heater
Voltage (CRT PWB)
about 6V?
Turn the Brightness
& Contrast control
to set Maximum
No Raster
Is whole
screen bright?
Check
G1 voltage about
-60V?
Is 100Vdc
line normal?
Does
the Brightness control
make screen
bright?
Is CRT
G2 (screen) voltage
about 730V?
Trouble in CRT
Raster OK
Yes
Yes
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Is input signal
normal?
One color is
missing
CRT
Cathode (Rk, Gk, Bk)
is normal?
Is video
output IC802
waveform normal?
Each grid (G1, G2)
voltage normal?
Is the
output of pre-amp
(IC801,TDA9210)
pin 14, 16,18 all
normal?
Check video signal cable or video card.
Trouble in IC801 or its ambient circuit
Trouble in video output IC802 or ambient
Trouble in 100Vdc line
Trouble in G1,G2 line
Replace CRT
No
No
No No
No
Yes
Yes
Yes
Yes
Yes
RK, GK, BK
About 40V p-p
0.7Vpp
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Is menu
key selected?
Is OSD Font
exist?
* If menu key selected.
Is Heater
Voltage about 6V?
Abnormal OSD Font
Is the
output of IC204
(pin 13, 14, 15)
normal?
Trouble in Heater voltage line.
Refer to trouble in P.S.U
Troubie in IC204 or its ambient circuit
Trouble in IC204 and its ambient circuit
One color is missing
Refer to Missing Color
No
No
Yes
Yes
Yes
Yes
No
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Is the
B+line voltage
over 50V?
Is the H-out
waveform of IC501
normal?
Trouble in IC501
Trouble in Horizontal
output circuit
(No Raster
Yes
No
Is the Collector
wave form of
Q504 normal?
Yes
Yes
Yes
Trouble in Q505
No
No
No
Trouble in Q505 and
its ambient circuit.
3V
0V
50V
Is the Drain
waveform of
Q507 normal?
Trouble in 50V
Trouble in Q506
0V
0V
70V
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Unstable
picture
Is the
pulse of pin 26 of
the IC501
correct?
Trouble in IC501 or its ambient circuit
Is the
pulse of pin 28 of
the IC201
correct?
Check IC501 and its ambient circuit
No
No
No
Yes
Yes
Is the
input H.Sync
correct?
Check IC201 and its ambient circuit
Yes
Trouble in Signal Cable or 15P D-Sub Connector
5Vpp
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Unstable
picture
Is the
12V,-12Vdc
line voltage is
correct?
Refer to P. S. U
Is the
pulse of pin 6 of
the IC401
correct?
Trouble in vertical D. Y
No
No
No
Yes
Yes
Is the output
of pin 8 of IC501
all normal?
Check IC401 and its ambient circuit
Yes
Check the IC501 and its ambient circuit
50Vp-p
40V
-10V
Page 23
Monitor remains
unfocused
Check
Focus VR in
FBT
Is
focus
acceptable?
Trouble in Focus
circuit (FBT)
Yes
OK
No
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Is
convergence
on the center area
bad?
Is
convergence on the
fringe area bad?
Adjust static convergence
Refer to Adjustment procedure of convergence
Yes
Adjust D.Y Location
Yes
No
Poor convergence
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Trouble in L503, C520 or their ambient circuit
Trouble in Horizontal output circuit Check the B+ and anode voltage of CRT.
Trouble in H.OSC/ Deflection Circuit
Refer to Horizontal Output circuit
Is
the DC level
of the base of Q517
changeable?
No
Yes
Is
the DC level
of IC501 pin 11
changeable ?
Yes
Check IC501 pin 11
Is the
collector pulse
of Q505 correct?
Is the
cathode waveform
of D509 correct?
Abnormal
H.Size
=1100Vp-p
80-310Vpp
* Normally anode voltage of CRT is approximately,
24.7KV
* Scan B+ are as follow :
No
Yes
Yes
No
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Is
changeable the
DC voltage of
IC401 pin 1?
Check the IC401 and its ambient circuit
Check the IC501 and its ambient circuit
No
No
Trouble V.OSC/ Deflection Circuit
Refer to V.OSC/Deflection circuit
Yes
Is
the 3.5Vdc of pin
21of the IC501?
Yes
Abnormal
V.Size
Page 27
Check the Base waveform of the Q515
Yes
Pincusion distortion
is excessive or barrel
O.K
Select the
side-pincushion
icon in OSD menu,
and adjust acceptable
position.
Yes
Is the
pin 11 waveform of
IC501
correct?
No
No
Trouble in IC501
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Is the
IC001
O.K?
Replace IC001
No
Is
voltage of C104
50Vdc?
No
Is
voltage of D002
130V (270V)?
Trouble in switching power transformer T001 or IC001 and its ambient circuit
Trouble in diode D001,D002,D003,D004 or peripheral device
No
Is the
waveform of T001
pin5 correct?
Trouble in T001 or D101
No
Trouble in P.S.U
Is
power switch
on?
Switch on
No
Yes
Yes
Yes
Yes
Yes
Yes
Is
voltage of C102
100Vdc?
Trouble in T001 or D102
No
Is
fuse F001
O.K?
Check the power cord outlet and diode D001,D002,D003,D004
No
A
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Is voltage
of C105
8Vdc?
Trouble in D103
No
Is voltage
of C109 13Vdc?
No
Yes
Yes
Yes
Is
voltage of C108
-12Vdc?
Trouble in D104 or vertical part
P.S.U O.K
Trouble in D106 or horizontal part
No
A
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531B/532B MONITOR BLOCK DIAGRAM
CRT
SOCKET
CRT : Orion Mini-Neck
15"
D -SUB
RGB H/V
Video Pre-am p (65MHz )
TDA921 0 (SGS Thompson)
OSD
NT6828
(Novatek)
CRT
Driver
TDA9536
(SGS
Thompson)
AC INPUT
SMPS
Transformer
MCU NT68P62 (Novatek)
H/V OSC Processor
TDA4856 (Philips)
V - Driver
KA2142B
(Samsun
g
)
PWM
D/A
IIC
Control
H/Linearity
Coil
TRL-531B
H/Def Output
TR/Damper
C/S Switchin
g
KSC5802/
SDS06F150S
(Fairchild)
IIC
Control
B+ PWM
EUT
Geometrical
Compensation
H/V Moire
Cancellation
Dynamic
Focus H/V
H-Driver
Drive
Transformer
B+
Booster
H-Size
TR : BD677A
(Fairchild)
FBT
H/V Converter
(Lienchan
g
)
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PCB LAYOUT
30
Main PCB Component Side
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31
Main PCB Solder Side
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