LG StudioWorks 575N User manual

COLOR MONITOR
SERVICE MANUAL
Website:http://biz.LGservice.com
E-mail:http://www.LGEservice.com/techsup.html
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CHASSIS NO. : CA-79
MODEL: StudioWorks 575N, 575E, CB575C
ID LABEL: CB575C-NA (MPR-II), CB575C-EA (TCO-99)
Same looking with New Chassis
Issue Date: AUGUST 2000

Apparaten skall anslutas till jordat nätuttag
Canadian ICES-003 Class B
Chassis No.:CA-66
This device complies with FDA Radiation Performance Standards,
21 CFR Subchapter J, and complies With part 15 of the FCC Rules.
Operation is subject to the following two conditions : (1)this device
may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may
cause undesired operation.
Warning : This product includes critical mechanical and electrical parts which are essential for X radiation safety. For
continued safety replace critical components indicated in the service manual only with exact replacement parts given in the
parts list. Operating high voltage for this product is 26kV at minimum brightness. Refer to service manual for measurement
procedures and proper service adjustments.
DIE IN DIESEM GERÄT ENTSTEHENDE
RÖNTGENSTRAHLUNG IST DURCH EINE EIGENSICHERE
KATHODENSTRAHLRÖHRE NACH ANLAGE III
RÖNTGENVERORDNUNG AUSREICHEND ABGESCHIRMT.
BESCHLEUNIGUNGSSPANNUNG : MAXIMAL 26kV
LISTED 59B9
ITE
E82982
LR53545
DHHS CODE:GG
MODEL NO. : CB575BN
POWER : AC100-240V
50/60Hz 1.5A
SERIAL NO. : 007KG00001
MANUFACTURED : JULY 2000
FCC ID : BEJCB575B
MADE IN KOREA
LG Electronics Inc.
LG Twin Towers, 20, Yoido-Dong,
Youngdungpo-Gu, Seoul, 150-721, Korea.
StudioWorks 575N
The Discrimination of Same Model Name
Model No: CB575BN
Manufactured: Before August 2000
Apparaten skall anslutas till jordat nätuttag
Canadian ICES-003 Class B
Chassis No.:CA-65
This device complies with FDA Radiation Performance Standards,
21 CFR Subchapter J, and complies With part 15 of the FCC Rules.
Operation is subject to the following two conditions : (1)this device
may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may
cause undesired operation.
Warning : This product includes critical mechanical and electrical parts which are essential for X radiation safety. For
continued safety replace critical components indicated in the service manual only with exact replacement parts given in the
parts list. Operating high voltage for this product is 27kV at minimum brightness. Refer to service manual for measurement
procedures and proper service adjustments.
DIE IN DIESEM GERÄT ENTSTEHENDE
RÖNTGENSTRAHLUNG IST DURCH EINE EIGENSICHERE
KATHODENSTRAHLRÖHRE NACH ANLAGE III
RÖNTGENVERORDNUNG AUSREICHEND ABGESCHIRMT.
BESCHLEUNIGUNGSSPANNUNG : MAXIMAL 27kV
LISTED 59B9
ITE
E82982
LR53545
DHHS CODE:GG
MODEL NO. : CB575BC
POWER : AC100-240V
50/60Hz 2.0A
SERIAL NO. : 006KG00001
MANUFACTURED : JUNE 2000
FCC ID : BEJCB575B
MADE IN KOREA
LG Electronics Inc.
LG Twin Towers, 20, Yoido-Dong,
Youngdungpo-Gu, Seoul, 150-721, Korea.
StudioWorks 575C
Model No: CB575BC
Manufactured: Before August 2000
Apparaten skall anslutas till jordat nätuttag
Canadian ICES-003 Class B
Chassis No.:CA-79
This device complies with FDA Radiation Performance Standards,
21 CFR Subchapter J, and complies With part 15 of the FCC Rules.
Operation is subject to the following two conditions : (1)this device
may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may
cause undesired operation.
Warning : This product includes critical mechanical and electrical parts which are essential for X radiation safety. For
continued safety replace critical components indicated in the service manual only with exact replacement parts given in the
parts list. Operating high voltage for this product is 25kV at minimum brightness. Refer to service manual for measurement
procedures and proper service adjustments.
DIE IN DIESEM GERÄT ENTSTEHENDE
RÖNTGENSTRAHLUNG IST DURCH EINE EIGENSICHERE
KATHODENSTRAHLRÖHRE NACH ANLAGE III
RÖNTGENVERORDNUNG AUSREICHEND ABGESCHIRMT.
BESCHLEUNIGUNGSSPANNUNG : MAXIMAL 25kV
LISTED 59B9
ITE
E82982
LR53545
DHHS CODE:GG
MODEL NO. : CB575C-NA
POWER : AC100-240V
50/60Hz 1.5A
SERIAL NO. : 007KG00001
MANUFACTURED : AUGUST 2000
FCC ID : BEJCB575C
MADE IN KOREA
LG Electronics Inc.
LG Twin Towers, 20, Yoido-Dong,
Youngdungpo-Gu, Seoul, 150-721, Korea.
StudioWorks 575N
Model No: CB575C-NA
Manufactured: After August 2000
Apparaten skall anslutas till jordat nätuttag
Canadian ICES-003 Class B
Chassis No.:CA-80
This device complies with FDA Radiation Performance Standards,
21 CFR Subchapter J, and complies With part 15 of the FCC Rules.
Operation is subject to the following two conditions : (1)this device
may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may
cause undesired operation.
Warning : This product includes critical mechanical and electrical parts which are essential for X radiation safety. For
continued safety replace critical components indicated in the service manual only with exact replacement parts given in the
parts list. Operating high voltage for this product is 26kV at minimum brightness. Refer to service manual for measurement
procedures and proper service adjustments.
DIE IN DIESEM GERÄT ENTSTEHENDE
RÖNTGENSTRAHLUNG IST DURCH EINE EIGENSICHERE
KATHODENSTRAHLRÖHRE NACH ANLAGE III
RÖNTGENVERORDNUNG AUSREICHEND ABGESCHIRMT.
BESCHLEUNIGUNGSSPANNUNG : MAXIMAL 26kV
LISTED 59B9
ITE
E82982
LR53545
DHHS CODE:GG
MODEL NO. : CB575C-EA
POWER : AC100-240V
50/60Hz 2.0A
SERIAL NO. : 006KG00001
MANUFACTURED : AUGUST 2000
FCC ID : BEJCB575C
MADE IN KOREA
LG Electronics Inc.
LG Twin Towers, 20, Yoido-Dong,
Youngdungpo-Gu, Seoul, 150-721, Korea.
StudioWorks 575E
Model No: CB575C-EA
Manufactured: After August 2000
*CA-65
*CA-79

1. PICTURE TUBE
Size : 15 inch (Flat Square Tube)
DefIection Angle : 90°
Neck Diameter : 29.1 mm
Transmission : 46%
Dot Pitch : 0.28 mm
Face Treatment : AR-ASC (Anti-Reflection and
Anti-Static Coating)
Low Radiation : MPR-II(S/W 575N)
TCO99(S/W 575E)
2. SIGNAL
2-1. Horizontal & Vertical Sync
1) Input Voltage Level: Low= ≤0.8V, High= ≥2.0V
2) Sync Polarity : Positive or Negative
2-2. Video Input Signal
1) Voltage Level : 0 ~ 0.7 Vp-p
a) Color 0, 0 : 0 Vp-p
b) Color 7, 0 : 0.467 Vp-p
c) Color 15, 0 : 0.7 Vp-p
2) Input Impedance : 75 Ω
3) Video Color : R, G, B Analog
4) Signal Format : Refer to the Timing Chart
2-3. Signal Connector
15-pin D-Sub Connector (Attached Type)
2-4. Scanning Frequency
Horizontal : 30 ~ 70 kHz
Vertical : 50 ~ 160 Hz
3. POWER SUPPLY
3-1. Power Range
AC 100~240V (Free Voltage), 50/60Hz, 1.5A Max.
3-2. Power Consumption
4. DISPLAY AREA
4-1. Active Video Area :
• 285 x 215 mm (11.22" x8.46") - Max Image Size
• 270 x 195 mm (10.63"x 7.68") - Preset Image Size
4-2. Display Color : Full Colors
4-3. Display Resolution : 1280 x 1024 / 60Hz
(Non-Interlace)
4-4. Video Bandwidth : 110 MHz
5. ENVIRONMENT
5-1. Operating Temperature: 15°C ~ 30°C (59°F ~ 86°F)
(Ambient)
5-2. Relative Humidity : 8%~ 80%
(Non-condensing)
5-3. Altitude : 3,000 m
6. DIMENSIONS (with TILT/SWIVEL)
Width : 360.0 mm (14.17")
Depth : 391.5 mm (15.41")
Height : 389.5 mm (15.33")
7. WEIGHT (with TILT/SWIVEL)
Net Weight : 12.4 kg (27.34 lbs)
Gross Weight : 14.6 kg (32.19 lbs)
CONTENTS
- 2 -
SPECIFICATIONS ................................................... 2
SAFETY PRECAUTIONS ........................................ 3
TIMING CHART ....................................................... 4
OPERATING INSTRUCTIONS ................................ 5
CONTROL LOCATIONS ......................................... 8
WIRING DIAGRAM ................................................. 9
DISASSEMBLY ..................................................... 10
BLOCK DIAGRAM ................................................. 12
DESCRIPTION OF BLOCK DIAGRAM...................13
ADJUSTMENT ...................................................... 15
TROUBLESHOOTING GUIDE .............................. 17
PRINTED CIRCUIT BOARD................................... 27
EXPLODED VIEW...................................................31
REPLACEMENT PARTS LIST ............................... 34
PIN CONFIGURATION........................................... 43
SCHEMATIC DIAGRAM......................................... 50
SPECIFICATIONS
MODE
NORMAL (ON)
STAND-BY
SUSPEND
OFF
H/V SYNC
ON/ON
OFF/ON
ON/OFF
OFF/OFF
POWER CONSUMPTION
less than 90 W
less than 15 W
less than 15 W
less than 5 W
LED COLOR
GREEN
ORANGE
ORANGE

SAFETY-RELATED COMPONENT WARNING!
There are special components used in this color monitor
which are important for safety. These parts are marked
on the schematic diagram and the replacement parts
list. It is essential that these critical parts should be
replaced with the manufacturer's specified parts to
prevent X-radiation, shock, fire, or other hazards. Do not
modify the original design without obtaining written
permission from LG or you will void the original parts and
labor guarantee.
CAUTION: No modification of any circuit should be
attempted.
Service work should be performed only after
you are thoroughly familiar with all of the
following safety checks and servicing
guidelines.
SAFETY CHECK
Care should be taken while servicing this color monitor
because of the high voltage used in the deflection circuits.
These voltages are exposed in such areas as the
associated flyback and yoke circuits.
FIRE & SHOCK HAZARD
An isolation transformer must be inserted between the
color monitor and AC power line before servicing the
chassis.
• In servicing, attention must be paid to the original lead
dress specially in the high voltage circuit. If a short
circuit is found, replace all parts which have been
overheated as a result of the short circuit.
• All the protective devices must be reinstalled per the
original design.
• Soldering must be inspected for the cold solder joints,
frayed leads, damaged insulation, solder splashes, or
the sharp points. Be sure to remove all foreign
materials.
IMPLOSION PROTECTION
All used display tubes are equipped with an integral
implosion protection system, but care should be taken to
avoid damage and scratching during installation. Use only
same type display tubes.
X-RADIATION
The only potential source of X-radiation is the picture tube.
However, when the high voltage circuitry is operating
properly there is no possibility of an X-radiation problem.
The basic precaution which must be exercised is keep the
high voltage at the factory recommended level; the normal
high voltage is about 24kV. The following steps describe
how to measure the high voltage and how to prevent X-
radiation.
Note : It is important to use an accurate high voltage
meter calibrated periodically.
• To measure the high voltage, use a high impedance
high voltage meter, connect (–) to chassis and (+) to
the CDT anode cap.
• Set the brightness control to maximum point at full
white pattern.
• Measure the high voltage. The high voltage meter
should be indicated at the factory recommended level.
• If the meter indication exceeds the maximum level,
immediate service is required to prevent the possibility
of premature component failure.
• To prevent X-radiation possibility, it is essential to use
the specified picture tube.
CAUTION:
Please use only a plastic screwdriver to protect yourself
from shock hazard during service operation.
SAFETY PRECAUTIONS
- 3 -

TIMING CHART
- 4 -
VIDEO
SYNC
CE
DF
AB
MODE
Resolution
Recall
H
O
R
I
Z
O
N
T
A
L
V
E
R
T
I
C
A
L
kHz
µs
µs
µs
µs
µs
µs
Hz
ms
ms
ms
ms
ms
ms
MARK
E
A
B
C
D
F
E
A
B
C
D
F
Sync Polarity
Frequency
Total Period
Video Active Time
Blanking Time
Front Porch
Sync Duration
Back Porch
Sync Polarity
Frequency
Total Period
Video Active Time
Blanking Time
Front Porch
Sync Duration
Back Porch
FACTORY PRESET MODE
MODE 1
+
53.674
18.631
14.222
4.409
0.569
1.138
2.702
+
85.061
11.756
11.179
0.577
0.019
0.056
0.502
800
x
600
85Hz
Yes
MODE 2
+
63.981
15.630
11.852
3.778
0.444
1.037
2.297
+
60.02
16.661
16.005
0.656
0.016
0.047
0.593
1280
x
1024
60Hz
Yes
MODE 3
+
68.677
14.561
10.836
3.725
0.508
1.016
2.201
+
84.997
11.765
11.183
0.582
0.015
0.044
0.523
1024
x
768
85Hz
Yes
MODE 4
+
46.875
21.333
16.162
5.171
0.323
1.616
3.232
+
75.00
13.333
12.800
0.533
0.021
0.064
0.448
800
x
600
75Hz
Yes
MODE 5
—
37.50
26.667
20.317
6.35
0.508
2.032
3.810
—
75.00
13.333
12.800
0.533
0.027
0.080
0.426
640
x
480
75Hz
Yes
MODE 6
—
31.469
31.780
25.420
6.36
0.640
3.810
1.91
—
70.082
14.270
12.710
1.56
0.413
0.064
1.083
720
x
400
70Hz
Yes

OPERATING INSTRUCTIONS
- 5 -
FRONT VIEW REAR VIEW
AC Power Socket
Signal Connector
ID Label
Power ON/OFF Button
See Front Control Panel
Front Control Panel
1. Power ON/OFF Button
This button is used to turn the monitor ON and OFF.
2. Power Indicator
This indicator lights up green when the monitor operates
normally; in DPMS (Energy Saving) mode, -stand-by,
suspend, or power off mode -its color changes to orange,
and if abnormal or damaging circuit turns out orange blink.
3. SET Button
This button to enter a selection in the on screen display.
4. OSD Select/Adjustment
Use for selecting (highlighting) an OSD icon and
adjusting level of the selected menu.
5. OSD Button
This button to enter or exit the on screen display.
12453

On-Screen-Display (OSD) Control
To adjust an image size, position, and operating
parameters are quick and easy with the On-Screen-
Display control system, using the ENTER button and the
OSD SET button. A quick example is given below to
familiarize yourself with use of the controls.
Example;
Note: (Monitor and PC’s power switch should be ON,
with an image or prompt on the screen).
1. Press the OSD ENTER /EXIT button , then the Main
menu of the OSD appears. Display will look like as
below:
2. To access a control, use the or Buttons.
When the icon you want becomes highlited, Press
the OSD SET Button.
3 .The adjustment OSD appears.
4. Use the / Buttons to adjust the level.
Display will look like as below:
5. Accept the changes by pressing the OSD SET
Button.
6. Exit the OSD by pressing the OSD ENTER/EXIT
Button.
Listed below are icons, icon names, and icon descriptions
of the OSD menu.
- 6 -
RGB
85
100
POSITION
RGB
85
100
POSITION
85
100
RGB
85
100
RGB
BRIGHTNESS CONTRAST BRIGHTNESS CONTRAST
Birghtness
To adjust the screen brightness level.
Contrast
To adjust the image contrast level.
RGB RGB
TEMP
RED
GREEN
BLUE
PRESET 6550K 9300K
TEMP
RED
GREEN
BLUE
PRESET 6550K 9300K
COLOR COLOR
6500K 9300K
To appear the display’s color temperature.
•6500K : Slightly reddish white
•9300K : Slightly Bluish white
TEMP
User easily color set without adjustment Red,
Green, Blue (R/ G/ B).
BRIGHTNESS CONTRAST
COLOR
RGB

- 7 -
RGB
85
100
RGB
85
100
POSITIONPOSITION
Vertical Position
To move the image up or down.
Horizontal Position
To move the image left or right.
POSITION
RGB
85
100
RGB
85
100
SIZE SIZE
Vertical Size
To adjust the image height.
Horizontal Size
To adjust the image width.
SIZE
SHAPE
RGB RGB
65
SHAPE
SHAPE
RGB
VIEDO LEVEL 0.7V
ON
ENGLISH
DDC OPTION
LANGUAGE
OSD POSITION
RGB
ON
ENGLISH
DDC OPTION
LANGUAGE
OSD POSITION
VIEDO LEVEL 0.7V
SETUP SETUP
Video Input Level
To select voltage level of the video card output - It is
input level of the monitor. Most video cards are 0.7V or
1.0V.
DDC (Display Data Channel)
To select the DDC function (ON or OFF).
Language
To choose the language in which the control names are
displayed. OSD Menus are available in six languages.
OSD Position
This item lets you adjust the OSD position.
SETUP
RGB
DEGAUSS ON
ON
H : 0 / V : 0
RECALL
MOIRE
68.6 kHz / 85.0 Hz
PRESET MODE
RGB
ON
H : 0 / V : 0
RECALL
MOIRE
68.6 kHz / 85.0 Hz
PRESET MODE
DEGAUSS ON
RGB
ON
RECALL
68.6 kHz / 85.0 Hz
PRESET MODE
DEGAUSS ON
MOIRE 12
12
SPECIAL
SPECIAL SPECIAL
SPECIAL
Pincushion
To correct bowing in or out of the image.
Pin Balance
To correct the balance of both sides bowing.
Trapezoid
To correct the geometric distortion.
Parallelogram
To correct the geometric distortion.
Rotate
To correct the image rotation.
Degaussing
Used to demagnetize the picture to give a move
account image and color.
Recall
If monitor is operating in a factory preset mode, this
control will reset the image to the factory preset mode.
Horizontal Moire
Reduce horizontal moire when interference patterns of
dark steady wary lines appear on your screen. The
moire adjustments may affect the focus of the screen.
Vertical Moire
Reduce vertical moire when interference patterns of
dark steady wary lines appear on your screen. The
moire adjustments may affect the focus of the screen.

CONTROL LOCATIONS
- 8 -
MAIN
FBT
CONTROL
1
2
3457
8
910
6
NO.
1
2
3
4
5
Ref. No.
SW207
SW205
SW206
SW204
SW202
NO.
6
7
8
9
10
Ref. No.
SW203
SW201
VR901
VR151
VR152
Control Function
POWER BUTTON
OSD SELECT/ADJUSTMENT(DOWN)
OSD SELECT/ADJUSTMENT(RIGHT)
SET BUTTON
OSD SELECT/ADJUSTMENT(LEFT)
Control Function
OSD SELECT/ADJUSTMENT(UP)
OSD BUTTON
B+ADJUSTMENT
TCO ADJUSTMENT
TCO ADJUSTMENT

WIRING DIAGRAM
- 9 -
P201
P401
P501 P151
WG2
P301
P302
P702
T1
P701
P402
P902
S+
S
CDT
EARTH
P1
Signal
Cable
AC
Socket
FBT

DISASSEMBLY
- 10 -
2. BACK COVER REMOVAL
1) Remove two screw caps (a).
2) Remove four screws (b).
3) Remove signal cable cap (c).
4) Slide the Back Cover away from the Front
Cabinet of the monitor.
(a)
1. TILT/SWIVEL REMOVAL
1) Set the monitor face downward.
2) Pressing the latch (a), carefully remove
the Tilt/Swivel by pulling it upward.
Anode Cap
DYAssembly Screw
P2
P151 P902
P401
P701
P702 P402
P501
(c)
(b)
(b)
(c)
(a)
3. TOTAL CHASSIS ASSEMBLY REMOVAL
1)
Remove connector (a) from the DY Assembly screw.
2) Disconnect P2(CDT EATH) and four pins (b)
from the Video PCB.
3) Carefully separate the CDT Board Assembly
from the CDT neck.
4) Discharge the remaining static electricity
by shorting between the Anode Cap
and the CDT ground.
5) Disconnect the Anode Cap
from the CDT.
6) Disconnect P902
(Degaussing pin),
P701 (DY pin), P151,
P401, and P501 from
the Main PCB.
7) Remove two screws (c).
8) Remove the Total Chassis
Assembly from the Main Frame.
(a)
(a)
(b)
(c)
(b)

- 11 -
P302
P301
P702 P402
(a)
(a)
(a)
(a)
(a)
(a)
4. CONTROL PCB ASSEMBLY REMOVAL
1) Remove two screws (a).
2) Remove the Control PCB Assembly
from the Front Cabinet.
5. VIDEO PCB ASSEMBLY REMOVAL
1) Disconnect P301, P302 from the Video PCB.
2) Remove four screws (a).
3) Remove the Video PCB Assembly.
(a)
(a)
(a)
(a)
6. BOTTOM BRACKET REMOVAL
1) Remove six screws (a).
2) Remove the Bottom Bracket.

BLOCK DIAGRAM
- 12 -
POWER INPUT
100~240VAC
(50/60Hz)
Line Filter
Degaussing Circuit
OSD ON/ OFF SET
< OSD Control >
SMPS
TRANS
(T901)
SMPS CONTROL (IC901)
DPM
CONTROL
CIRCUIT
5V
Regulator
105V 50V 15V 6.3V
TILT
Control Circuit
6.3V
15V
E2PROM (IC402)
H / V POSITION H / V SIZE SPCC TRAPIZODE PIN BALANCE PARALLELOGRAM ROTATION RECALL DEGAUSS DDC OPTION COLOR CURVE MOIRE LANGUAGE RECALL VIDEO LEVEL BRIGHTNESS CONTROL OSD POSITION
5V
OSD IC (IC301)
H-Sync Sig V-Sync Sig I2C DATA(SDA) I2C CLOCK(SCL)
VIDEO PRE-AMP (IC302)
Signal
Cable R
G
BVIDEO
MAIN AMP (IC303)
5V
5V
H/V Sync Processor
( IC701 )
TDA4856 V-OUT
( IC601)
TDA4866
H-OUT
( Q706)
H-Linearity
Correction
DC/DC Converter
X-RAY
Protection
Circuit
FBT
( T701 )
Auto Beam Limit
Vertical Blanking,
Brightness Control
- 120V
40V
-200V
15V
D/D Feed Back
12V
MICOM (IC401) SCL / SDA
H/V Sync,
PWM Control
15V
6.3V 15V
105V
15V
50V
DY CDT
Heater ( 6.3V )
I2C
I2C
I2C
H/V
Sync
G1
Screen
Dynamic Focus
Static Focus
H.V
R/G/B
Drive/Contrast
Cut-Off
H-DRV
B-DRV
B+
15V
POWER
TILT
COIL
DEGAUSSING
COIL
I2C
Vout 1 Vout 2
TCO

DESCRIPTION OF BLOCK DIAGRAM
- 13 -
1. Line Filter & Associated Circuit.
This is used for suppressing noise of power input line
flowing into the monitor and/or some noise generated in
this monitor flowing out through the power input line.
That is to say, this circuit prevents interference between
the monitor and other electric appliances.
2. Degauss Circuit & Coil.
The degauss circuit consists of the degaussing coil, the
PTC(Positive Temperature Coefficient) thermistor(TH901),
and the relay(RL901). This circuit eliminates abnormal
color of the screen automatically by degaussing the
shadow mask in the CRT during turning on the power
switch. When you need to degauss in using the monitor,
select DEGAUSS on the OSD menu.
3. SMPS(Switching Mode Power Supply).
This circuit is working of 90~264V AC(50/60Hz).
The operation procedure is as follows:
1) AC input voltage is rectified and smoothed by the
bridge diodes (D901~D904) and the capacitor (C908).
2) The rectified voltage(DC) is applied to the primary
coil of the transformer(T901).
3) The control IC(IC901) generates switching pulse to
turn on and off the primary coil of the transformer
(T901) repeatedly.
4) Depending on turn ratio of the transformer, the
secondary voltages appear at the secondary coils of
the transformer(T901).
5) These secondary voltages are rectified by each
diode(D941, D951, D961, D971) and operate other
circuit. (horizontal and vertical deflection, video
amplifier, ...etc.)
4. X-ray Protection.
I f the high voltage of the FBT reaches up to 29kV (abnormal
state), Q807 operates and IC401(MICOM) pin 41 come to
low level. Then MICOM control IC701 (Deflection controller)
to stop Horizontal drive pulse and stop Horizontal Deflection.
5. Micom(Microprocessor) Circuit.
The operating procedure of Micom(Microprocessor) and its
associated circuit is as follows:
1) H and V sync signal is supplied from the signal cable.
2) The Micom(IC401) distinguishes polarity and
frequency of H and V sync.
3) The Micom sets operating mode and offers the
controlled data. (H-size, H-position, V-size, ... etc.)
4) The controlled data of each mode is stored in itself.
5) User can adjust screen condition by each OSD
function. The data of the adjusted condition is stored
in EEPROM(IC402).
6. Horizontal and Vertical Oscillation.
This circuit generates the horizontal pulse and the vertical
pulse by taking the H and V sync signal.
This circuit consists of the TDA4856(IC701) and the
associated circuit.
7. D/D(DC to DC) Converter.
This circuit supplies DC voltage to the horizontal deflection
output circuit by increasing DC 50V which is the
secondary voltage of the SMPS in accordance with the
input horizontal sync signal.
8. Side-Pincushion & Trapezoid Correction Cirucit.
This circuit improves the side-pincushion and the
trapezoid distortion of the screen by mixing parabola and
saw-tooth wave to output of the horizontal deflection D/D
converter which is used for the supply voltage(B+) of the
deflection circuit.
9. Horizontal Deflection Output Circuit.
This circuit makes the horizontal deflection by supplying
the saw-tooth current to the horizontal deflection yoke.
10. High Voltage Output & FBT(Flyback Transformer).
The high voltage output circuit is used for generating pulse
to the primary coil of the FBT(Flyback Transformer
(T701)). A boosted voltage(about 25.5kV) appears at the
secondary of the FBT and it is supplied to the anode,
focus, and screen voltage of the CRT.
11. H-Linearity Correction Circuit.
This circuit corrects the horizontal linearity for each
horizontal sync frequency.
12. Vertical Output Circuit.
This circuit takes the vertical ramp wave from the
TDA4856(IC701) and performs the vertical deflection by
supplying the saw-tooth current to the vertical deflection
yoke.
13. TCO Circuit.
This circuit takes -200V from FBT and radiate (-) electric
wave to reduce (+) electric wave radiated from front of
CDT.

- 14 -
14. H& V Blanking and Brightness Control.
Blanking circuit eliminates retrace line by supplying
negative pulse to the G1 of the CRT. And Brightness
circuit is used for control of the screen brightness by
changing DC level of the G1.
15. Image Rotation (Tilt) Circuit.
This circuit corrects the tilt of the screen by supplying the
image rotation signal to the tilt coil which is attached near
the deflection yoke of the CRT.
16. Video Pre-Amp Circuit.
This circuit amplifies the analog video signal from 0-0.7V
to 0-4V. It is operated by taking the clamp, R, G, B drive
and contrast signal from the Micom(IC401).
17. Video Output Amp Circuit.
This circuit amplifies the video signal which comes from
the video pre-amp circuit and amplified it to applied the
CRT cathode.

ADJUSTMENT
- 15 -
GENERAL INFORMATION
All adjustment are thoroughly checked and corrected
when the monitor leaves the factory, but sometimes
several adjustments may be required.
Adjustment should be following procedure and after
warming up for a minimum of 30 minutes.
•Alignment appliances and tools.
- IBM compatible PC.
- Programmable Signal Generator.
(eg. VG-819 made by Astrodesign Co.)
- EPROM or EEPROM with saved each mode data.
- Alignment Adaptor and Software.
- Digital Voltmeter.
- White Balance Meter.
- Luminance Meter.
- High-voltage Meter.
AUTOMATIC AND MANUAL DEGAUSSING
The degaussing coil is mounted around the CDT so that
automatic degaussing when turn on the monitor. But a
monitor is moved or faced in a different direction, become
poor color purity cause of CDT magnetized, then press
DEGAUSS on the OSD menu.
ADJUSTMENT PROCEDURE & METHOD
-Install the cable for adjustment such as Figure 1and run
the alignment program on the DOS for IBM compatible PC.
-Set external Brightness and Contrast volume to max position.
1. Adjustment for B+ Voltage.
1) Display cross hatch pattern at Mode 3.
2) Adjust voltage to 51V
± 0.5Vdc with VR901.
2. Adjustment for High-Voltage.
1) Run alignment program for CB575C on the IBM
compatible PC.
2) Display cross hatch pattern at Mode 3.
3) DIST.ADJ→CTRL PWM →High Voltage Command.
4) Adjust High Voltage to 24.5kV
± 0.1 kVdc.
5) Press Enter Key.
3. Adjustment for Factory Mode (Preset Mode).
1) Display cross hatch pattern at Mode 3.
2) Run alignment program for CB575C on the IBM
compatible PC.
3) Power button of the monitor turn off →turn on.
4) COMMAND →START →Y(Yes) command.
5) DIST. ADJ. →CTRL PWM → TILT command.
6) Adjust tilt as arrow keys to be the best condition.
7) DIST. ADJ. →BALANCE command.
8) Adjust balance of side-pincushion as arrow keys to
be the best condition.
9) DIST. ADJ. →BALANCE command.
10) Adjust parallelogram as arrow keys to be the best
condition.
11) DIST. ADJ. →FOS. ADJ command.
12) Adjust V-SIZE as arrow keys to 230 ±
2mm.
13) Adjust V-POSITION as arrow keys to center of the
screen.
14) Adjust H-SIZE as arrow keys to 310 ± 2mm.
15) Adjust H-POSITION as arrow keys to center of the
screen.
16) Adjust S-PCC (Side-Pincushion) as arrow keys to be
the best condition.
17) Adjust TRAPEZOID as arrow keys to be the best
condition.
18) Display from Mode 1 to Mode 4 and repeat above
from number
12) to 17) .
19) PRESET EXIT →Y (Yes) command.
4. Adjustment for White Balance and Luminance.
1) Set the White Balance Meter.
2) Press the DEGAUSS on the OSD menu for
demagnetization of the CDT.
3) COLOR ADJ. →LUMINANCE command of the
alignment program.
4) Set Brightness and Contrast to Max and ABL to
200(C8) (decimal) position.
5) Display color 0,0 pattern at Mode 3.
6) COLOR ADJ. →BIAS ADJ. command of the
alignment program.
7) Check whether green color or not at R-BIAS and B-
BIAS to min position and G-BIAS to 127(7F) to
position. Set Sub-Brightness to 80(Decimal). Adjust
G2(Screen) Volume on FBT to 0.5
± 0.05FL of the
raster luminance. Check it's not green color.
8) Adjust R-BIAS and B-BIAS command to x=0.283
±
0.005 and y=0.298 ± 0.005 on the White Balance
Meter with PC arrow keys.
9) Adjust SUB-Brightnesscommand to 0.5 ± 0.1FL of the
raster luminance.
10) Display color 15,0 box pattern (70x70mm) at Mode 3.
11) DRIVE ADJ command.
12) Set SUB-Contrast 70(46) (decimal) position.
13) Set G-DRIVE to 150(96) (decimal) at DRIVE of the
alignment program.

- 16 -
Figure 1. Cable Connection
14) Adjust R-DRIVE and B-DRIVE command to white
balance x=0.283
± 0.003 and y=0.298 ± 0.003 on the
White Balance Meter with PC arrow keys.
15) Adjust SUB-CONTRAST command to 50 ± 2FL of the
color 15,0 box pattern (70x70mm) luminance at
mode 4 and save in color 1.
16) Display color 15,0 full white patten at Mode 3.
17) COLOR ADJ. →LUMINANCE →ABL command.
18) Adjust ABL to 34 ± 1FL of the luminance.
19) Exit from the program.
5. Adjustment for Focus.
1) Set the Brightness and Contrast to max position.
2) Display H character in full screen at Mode 3.
3) Adjust two Focus control on the FBT that focus
should be the best condition.
220
Monitor to be
adjusted
Video
Signal
Generator
IBM
Compatible PC
Parallel Port
Power inlet (required)
Power LED
ST Switch
Power Select Switch
(110V/220V)
Control Line
Not used
RS232C
PARALLEL
V-SYNC POWER
ST
VGS MONITOR
E
E
V-Sync On/Off Switch
(Switch must be ON.)
F
F
A
A
B
B
C
C
1510
5
569
1
1
1
14
13
25
6
5V
5V
5V
4.7K
4.7K
4.7K
74LS06
74LS06
OFF ON
OFF
ON
11

TROUBLESHOOTING GUIDE
- 17 -
NO POWER
(POWER INDICATOR OFF)
TROUBLE IN
D901, D902, D903, D904
TROUBLE IN FUSE
(F901)
TROUBLE IN
IC901
TROUBLE IN
D941, D951, D961,
D971
TROUBLE IN
IC950, Q972, Q971,
Q952, Q951, Q942, Q941
CHECK
FUSE OK?
CHECK
C908 VOLTAGE?
(AC120V: 160VDC,
AC220V: 304VDC)
NO
YES
YES
YES
YES
NO
NO
NO
CHECK
IC901 PIN 6
WAVEFORM
(SQUARE WAVE
COMES OUT?)
CHECK
D941, D951, D961,
D971
VOLTAGE?
1. NO POWER

- 18 -
2. NO CHARACTER
NO CHARACTER
CHECK
IC302
PIN 20(6.3V) ?
CHECK
IC302 PIN 1, 3, 5?
CHECK
IC302 PIN 14, 16, 18 ?
CHECK
IC303
PIN 1, 5, 11 ?
CHECK
IC303 PIN 4 (105V)
PIN 8 (15V) ?
TROUBLE IN
P302 6.3V LINE
TROUBLE IN
PC SIGNAL,
P301 SIGNAL CABLE
TROUBLE IN
IC302
TROUBLE IN
P303 15V LINE/
105V LINE
TROUBLE IN IC303
NO
YES
NO
NO
YES
YES
YES
YES
NO
NO
CHECK
R, G, B CATHODE
VOLTAGE?
TROUBLE IN
R341~R343,
R351~R353, L301~L303,
D307~D312
TROUBLE IN
CRT SOCKET
YES
NO

- 19 -
NO VIDEO
(POWER INDICATOR ON)
CHECK
POWER INDICATOR
GREEN or ORANGE?
CHECK
D712 ANODE
(-120V)?
CHECK
G1VOLTAGE?
(-35~-15V)
TROUBLE IN
D712
TROUBLE IN
Q704
DPM MODE
(NO H and/or V SYNC)
ORANGE
NO
GREEN
YES
NO
3. NO RASTER
CHECK
CDT HEAT
VOLTAGE? (6.3V)
TROUBLE IN
D941, Q942, Q941
YES
NO
TROUBLE IN
CDT
YES