LG StudioWorks N2200P 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.
MODEL: StudioWorks N2200P (NB230A-UA)
CHASSIS NO. : CA-94
FACTORY MODEL: NB230A
*( ) ID LABEL Model No.

1. PICTURE TUBE
Size : 22 inch (20 inches viewable)
Natural Flat Tube
DefIection Angle : 90°
Neck Diameter : 29.1 mm
Grille Pitch : 0.24 mm
Diagonal Size : 507.6mm
Face Treatment : Sputter coating,
ARASC Coating
2. SIGNAL
2-1. Horizontal & Vertical Sync
1) Input Voltage Level: Low≤0.8V, High≥2.1V
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 / 5 BNC Connector
2-4. Scanning Frequency
Horizontal : 30~124kHz
Vertical : 50~160 Hz
3. POWER SUPPLY
3-1. Power Range
AC 100~240V 50/60Hz, 2.0A.
3-2. Power Consumption
4. DISPLAY AREA
4-1. Active Video Area
• Max Image Size - 406.4 x 304.8mm(16.00" x 12.00")
• Preset Image Size - 390 x 293mm(15.35" x 11.53")
4-2. Display Color : Full Colors
4-3. Display Resolution : 2048 x 1536 / 75Hz
4-4. Video Bandwidth : 350 MHz
5. ENVIRONMENT
5-1. Operating Temperature: 5°C~35°C (41°F~95°F)
(Ambient)
5-2. Relative Humidity : 10%~90%
(Non-condensing)
5-3. Altitude : 5000 m
6. DIMENSIONS (with TILT/SWIVEL)
Width : 503 mm (19.8")
Depth : 477 mm (18.8")
Height : 509 mm (20.4")
7. WEIGHT (with TILT/SWIVEL)
Net Weight : 31.3 kg (69.01lbs)
Gross Weight : 35.5 kg (78.27lbs)
8. USB
USB standard : Rev 1.1complied BUS-powered hub
Downstream power supply : 500mA for each (MAX)
Communication speed : 12 Mbps (full), 1.5 Mbps (low)
USB port : 1 Upstream port / 4 Downstream ports
CONTENTS
SPECIFICATIONS
- 2 -
SPECIFICATIONS ................................................... 2
SAFETY PRECAUTIONS ........................................ 3
TIMING CHART ....................................................... 4
OPERATING INSTRUCTIONS ................................ 5
CONTROL LOCATIONS ........................................ 11
WIRING DIAGRAM ............................................... 12
BLOCK DIAGRAM ................................................. 13
DESCRIPTION OF BLOCK DIAGRAM...................14
ADJUSTMENT ...................................................... 16
TROUBLESHOOTING GUIDE .............................. 17
EXPLODED VIEW.................................................. 25
REPLACEMENT PARTS LIST .............................. 27
PIN CONFIGURATION ...........................................38
SCHEMATIC DIAGRAM..........................................40
PRINTED CIRCUIT BOARD................................... 44
MODE
NORMAL
Stand BY
Suspend
OFF
H/V SYNC
ON/ON
OFF/OFF
OFF/OFF
OFF/OFF
POWER CONSUMPTION
less than 115W(130W)
less than 8W(20W)
less than 8W(20W)
less than 3W(18W)
LED COLOR
GREEN
YELLOW
YELLOW
YELLOW
*( ) : with USB

SAFETY PRECAUTIONS
- 3 -
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 manufacturer 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 27kV. 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.

TIMING CHART
- 4 -
VIDEO
SYNC
D
A
EF
BC
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
kHz
µs
µs
µs
µs
µs
µs
Hz
ms
ms
ms
ms
ms
ms
MARK
A
B
C
D
E
F
A
B
C
D
E
F
H
O
R
I
Z
O
N
T
A
L
V
E
R
T
I
C
A
L
MODE VESA GTF
MODE 1
—
31.469
31.778
25.422
6.356
0.640
3.810
1.906
—
59.940
16.683
15.253
1.430
0.318
0.064
1.049
640
x
480
60Hz
Yes
MODE 2
+
53.674
18.631
14.222
4.409
0.569
1.138
2.702
+
85.061
11.756
11.178
0.578
0.019
0.056
0.503
800
x
600
85Hz
Yes
MODE 3
+
60.023
16.660
13.003
3.657
0.203
1.219
2.235
+
75.029
13.328
12.795
0.533
0.017
0.050
0.466
1024
x
768
75Hz
Yes
MODE 4
+
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 5
+
79.976
12.504
9.481
3.022
0.119
1.067
1.837
+
75.025
13.329
12.804
0.525
0.013
0.038
0.475
1280
x
1024
75Hz
Yes
MODE 6
+
91.146
10.971
8.127
2.844
0.406
1.016
1.422
+
85.024
11.761
11.235
0.527
0.011
0.033
0.483
1280
x
1024
85Hz
Yes
MODE 7
+
93.750
10.667
7.901
2.765
0.316
0.948
1.501
+
75.000
13.333
12.800
0.533
0.011
0.032
0.490
1600
x
1200
75Hz
Yes
MODE 8
+
106.250
9.412
6.972
2.441
0.279
0.837
1.325
+
85.000
11.765
11.294
0.470
0.009
0.028
0.433
1600
x
1200
85Hz
Yes
MODE 9
—
121.950
8.200
5.864
2.336
0.504
0.664
1.168
+
75.000
13.333
12.595
0.740
0.100
0.025
0.615
2048
x
1536
75Hz
Yes
Resolution
Recall

OPERATING INSTRUCTIONS
- 5 -
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, -
DPM off mode - it color changes to yellow.
3. MENU(or OSD) Button
Use this button to enter or exit the on screen display.
4. ▲▼/◀▶ Buttons
Use these buttons to choose or adjust items in the on
screen display.
REAR VIEWFRONT VIEW
Front Control Panel
HD
BGR
AC IN VD D-SUB
Front Control Panel
Power ON/OFF
Button
Power Indicator
D-Sub
Signal Connector
BNC Connector
AC Power Socket
124 5 7 86 3
The Contrast and Brightness functions are also
available in the On Screen Display (OSD) menu.
▶Button
▲Button
Bring up Contrast adjustment
Bring up Brightness adjustment
◀Button
Brings up the clearness of the image :
letters, pictures or moving pictures.
SHARPNESS
For seeing letters
For seeing pictures or the photographs
For seeing moving pictures

- 6 -
5. Select (or SET) Button
Use this button to enter a selection in the on screen
display.
6. Auto adjustment function
When adjusting your display settings, always press
the AUTO button before entering the On Screen
Display(OSD). This will automatically adjust your
display image to the ideal settings for the current
screen resolution size (display mode).
The best display mode is 1600 x 1200.
7. INPUT Button
Use this button to make Dsub or BNC connector
active. This feature is used when two computers are
connected to the display. The default setting is Dsub.
8. D-Sub Indicator
This indicator turns on when D-sub is selected.
It turns off when BNC is selected.
On-Screen-Display (OSD) Control
Making adjustments to the image size, position and operating
parameters of the monitor is quick and easy with the On
Screen Display Control system.
A short example is quick and easy given below to familiarize
you with the use of the controls. The following section is an
outline of the available adjustments and selections you can
make using the OSD.
To make adjustments in the On Screen Display, follow these
step:
Example;
Note: (Monitor and PC’s power switch should be ON,
with an image or prompt on the screen).
1. Press the MENU Button, then the main menu of
the OSD appears.
2.To access a control, use the or Buttons.
When the icon you want becomes highlighted,
press the SELECT Button.
3. Use the Buttons to adjust the item
to the desired level.
4. Accept the changes by pressing the SELECT
Button.
5. Exit the OSD by pressing the MENU Button.
Listed below are icons, icon names, and icon descriptions
of the OSD menu.
BRIGHTNESS CONTRAST
Birghtness
To adjust the brightness of the screen.
Contrast
To adjust the contrast of the screen.
POSITION
Vertical Position
To move image up and down.
Horizontal Position
To move image left and right.

- 7 -
Vertical Size
To adjust the image height.
Horizontal Size
To adjust the image width.
SIZE
SHAPE
SHAPE
COLOR
H. Linearity
To adjust the horizontal width of edge of the image.
V. Linearity
To adjust the vertical width of edge of the image.
Recall
You can use this function to reload the modified parameters for
screen display operation, as specified by the user after purchase:
Zoom, H/V Linearity (These recalled options may differ depending
on the mode selected: Preset, User, or New).
6500K/ 9300K
Select the screen color.
•6500K: Slightly reddish white.
•9300K: Slightly bluish white.
Select the screen temperature which you
prefer among reddish or bluish or any color
in between.
Set your own color levels.
PRESET
TEMP
RED
GREEN
BLUE
Side Pincushion
To correct a concave or convex bowing of the image.
Side Pincushion Balance
To correct the balance of both sides bowing.
Parallelogram
To correctly adjust the skew of the image.
Trapezoid
To correct geometric distortion.
Top Corner
Bottom Corner
To correct an irregular distortion of the displayed image.
Recall
You can use this function to reload the modified parameters for
screen display operation, as specified by the user after purchase:
Side Pincushion, Side Pincushion Balance, Parallelogram,
Trapezoid, Top Corner, Bottom Corner (These recalled options
may differ depending on the mode selected: Preset, User, or New).
Zoom
To simultaneously adjust horizontal and vertical size of the image.

- 8 -
This item is used to select the monitor's
input signal level. The normal level used for
most PCs is 0.7V.
If the screen becomes suddenly washed-
out or blurred, please select 1.0V and try
again.
To choose the language in which the
control names are displayed.
OSD Menus are available in 11 languages:
English, German, French, Spanish, Italian,
Swedish, Finnish, Portuguese, Korean,
Chinese and Russian.
To adjust position of the OSD window on
the screen.
Return to all factory default settings except
"LANGUAGE, BRIGHTNESS, CONTRAST"
In case of input SOG (Sync On Green)
Video Signal, the back raster will appear
green. Then, select the SOG (Sync On
Green) in the clamp, it goes back to the
original back raster.
VIDEO LEVEL
LANGUAGE
OSD POSITION
RESET
CLAMP
To manually demagnetize the screen to
avoid showing incorrect images or colors.
This is to have the real color of the image.
This will automatically adjust your display
image to the ideal settings for the current
screen resolution size (display mode).
This is to adjust the clearness of the screen.
It is recommended to use this to see movies
or moving picture.
This item allows you to reduce the degree
of moire. (Moire is caused by interference
Horizontal Scan Line with the periodical dot
screen). It is normally OFF(H:0/V:0).
The moire adjustments may affect the focus
of the screen.
Moire adjustments may shake slightly while
the moire reduction function is on.
Use to adjust the purity on the screen if the
color appears uneven.
This is to adjust the alignment of red and
blue fields.
DEGAUSS
NATURAL
COLOR
AUTOSIZING
SHARPNESS
MOIRE
PURITY
CONVER-
GENCE
SETUP SPECIAL
DEGAUSS ON
AUTO SIZING ON
SHARPNESS
NATURAL COLOR OFF
MOIRE
CONVERGENCE
PURITY

- 9 -
Making use of USB (Universal Serial Bus)*
USB (Universal Serial Bus) is an innovation in connecting your different desktop peripherals conveniently to your computer.
By using the USB, you will be able to connect your mouse, keyboard, and other to your monitor instead of having to
connect them to your computer. This will give you greater flexibility in setting up your system. USB allows you to connect
chain up to 120 devices on a single USB port, and you can “hot”plug (attach them while the computer is running) or unplug
them while maintaining Plug and Plug auto detection and configuration. This monitor has an integrated BUS-powered USB
hub, allowing up to 4 other USB devices to be attached it.
USB connection
1. Connect the upstream port of the Display to the downstream port of the USB compliant PC or another hub using the
USB cable. (Computer must have a USB port)
2. Connect the USB compliant peripherals to the downstream ports of the monitor.
USB downstream Ports
connect the cables from USB
compliant peripherals-such as
keyboard, mouse, etc
To USB downstream port of
the USB compliant PC or
another hub cable
NOTE
To activate the USB hub function, the monitor must be connected to a USB compliant PC(OS) or another hub with the
USB cable(enclosed).
When connecting the USB cable, check that the shape of the connector at the cable side matches the shape at the
connecting side.
Even if the monitor is in a power saving mode, USB compliant devices will function when they are connected the USB
ports(both the upstream and downstream) of the monitor.
This is a simplified representation
of the rear view. This is a simplified representation of the side view.

Using the BNC connector with other types of video cards
- 10 -
*
R
G
B
HD VD
Using the BNC connectors with other types of video cards. Follow the example that fits your
needs.
1. In case of using a composite sync on green video signal(Sync On Green):
Connect each R,G and B video signals to BNC receptacles on the back of the monitor.
2. In case of using an external composite sync signal:
Connect each R, G and B video signals and composite sync signal to the BNC receptacles on the rear panel.
3. In case of using a separate horizontal and vertical sync signal:
Connect each R, G and B video signals and the horizontal and vertical sync signal to BNC receptacles on rear
panel.
R
G
B
Blue Green Red
Blue
Gray Bllack
Green
NOTE
This package does not include the BNC connectors but you can purchase them at your local computer stores.
This monitor does not support the DDC function, if you use the
5 BNC connectors with other types of video cards.
R
G
B
HD
*
Blue
Gray
Green
Red
Red

CONTROL LOCATIONS
- 11 -
VR711: RASTER
CENTERING
VR501: High Voltage
Adjustment
VR951: B Adjustment
(195V)
+

WIRING DIAGRAM
- 12 -
P661
P611
P101
P102
P201
P306
P305
P202
P207
P203
P951
P703
P702
P631
P820
P952
P904
P901
P903
P104
P103
P303
Anode Cap
Degaussing
Coil
to P611
P704 P601
P701
P651
to P631
to P651
to P661
to P601

BLOCK DIAGRAM
- 13 -
5V
POWER OFF STBY & SUS
8 BIT MICOM (IC271)
D-SUB
(SIGNAL CABLE) EEPROM
(IC272)
VIDEO Pre Amp
CXA2153S
(IC302) Video Amp
LM2412
(IC303)
CRT
R/G/B
CLAMP
CONTRA
ST
OSD SIGNAL (R/G/B)
OSD PROCESSOR
(IC301)
12V
H-SYNC SIGNAL V-SYNC SIGNAL.
Degaussing Coil
Degaussing
circuit
(RL901)
POWER
& DPM
LED
LINE FILTER (LF901)
PWM IC (IC905)
SMPS
Main
(T951)
RECTIFIER D901
7.5V
28V
15V
12V
-15V
80V
210V
H/V Sync
Processor
TDA4856
(IC201)
12V H-out
2SC5597
(Q705)
SPCC &
H-size mixing
(IC2041)
H-LINRARITY CORRECTION (Q752,754,756,758 760,762)
High-voltage
PWM IC
M62501P
(IC501)
D/D CONVERTER
(Q405)
DYNAMIC FOCUS VR DYNAMIC FOCUS VR SCREEN VR
SCREEN
Dynamic Focus
High-voltage
V-out
TDA8177
(IC601)
CLAMP CONTROL
TILT Control (IC651)
Dynamic Focus
output
LF353
(IC291)
5V
H-SIZE
MUTE
5V
FLY
BACK
TRANS
(T501)
80V
R/G/B
R/G BIAS
210V
15V
V-SAW
H-SYNC
V-SYNC
LED
DEG
STBY&SUS
Control panel
R
G
SMPS
Sub
(T901)
5V 6.3V
IIC-SDA
IIC-SCL
STC Control
(IC261)
IIC-SDA
IICC-SCL
DDC-SDA DDC-SCL
EW
H-DRV
SDA
SCL
IIC-SDA
IICC-SCL
IIC SIGNAL
X-RAY
H/V DETECT
FBT DRIVE
& SWITCHING
(Q515,516)
H-drive Trans
B+ CONTROL
(Q701,702,Q703)
D/D DRIVE (IC402)
DF
H-CENTERING
COIL
210V
DUMY FBT
(T702)
195V
H-drive Trans
(T701)
F/V
DF B+
AFC
AFC
AFC
D/D CONVER
(Q525)
80V
D-FOUS AMP
15V
DF
15V
15V X-RAY
15V
Power input 90~132Vac 180~264Vac ( 50/60Hz )
CS1
CS2
CS3
CS4
CS5
CS0
USB-DOWNUSB-UP
USB CONTROL (IC501)
5-BNC
-15V
I/O EXPANDER
M62320
(IC791)
CS1 CS2 CS3 CS4 CS5 CS0
RL1
15V
RL2
IIC-SDA
IICC-SCL
RELAY
28V
4-CORNER PURITY
Control(IC611,631,651)
DAC
M62393 (IC691)
IIC-SDA
IICC-SCL
H-STC V-STC TILT
T/L B/L T/R B/R
POWER AUTO ADJUST ADJUST ADJUST ADJUST MENU SELECT INPUT
H-SYNC V-SYNC RESET SOG-IN UNLOCK IIC-SDA IIC-SCL DDC-SDA DDC-SCL
LED
BNC/DSUB
KEY2 ST-IN KEY1
H-Conv. V-Conv
EBRT
UMUTE
SOG/SEP

DESCRIPTION OF BLOCK DIAGRAM
- 14 -
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 slot mask in the CRT when turn on the
power switch. When you need to degauss while using
the monitor select DEGAUSS in the SPECIAL on the
OSD menu.
3. SMPS(Switching Mode Power Supply).
This circuit works with power of 90~264Vac(50/60Hz).
The operation procedure is as follows:
1) AC input voltage is rectified and smoothed by the
bridge diode (D901) and capacitors (C905).
2) The rectified voltage (DC voltage) is applied to the
primary coil of the transformer (T901,T951)
3) The control IC (IC951) generates switching pulse to
turn on and off the primary coil of the transformer
(T951) repeatedly.
4) Depending on the turn ratio of the transformer , the
secondary voltages appear at the secondary coil of
the transformer (T951).
5) These secondary voltages are rectified by each
diode(D957,958,951,959,960,961,962) and operate
the other circuits. (Deflection , Video Amplifier ,.....
etc.)
The switching IC (IC951) controls input-pulse-width
and generates secondary voltages by sub-transformer
(T901)
4. Display Power Management Circuit.
This circuit control power consumption of the monitor
by detecting H and V sync signal.
There are Stand-by and suspend mode.
When no horizontal or vertical sync signal input, the
circuit consists of IC903 becomes stand-by and
suspend mode. Its power consumption is below 8W.
5. X-ray Protection.
This circuit detects the rectified DC voltage comes
from the FBT pin 6. If the high volltage of the FBT
reaches up to about 30kV (abnormal state) , high
voltage control PWM IC (IC501) detects it. And PWM
IC (IC501) prevent output voltage to the gate of
switching FET(Q525).It stops operating primary circuit
of the FBT (T501), and high voltage is not be
generated.(In the normal state, the high voltage is
about 27kV.)
6. 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 D-sub to the
Micom (IC271).
2) The Micom (IC271) distinguishes polarity and
frequency of H and V sync.
3) The Micom controls each OSD function signals.(H-
size, H-position, V-size, etc.)
4) The controlled data of each mode is stored in itself.
User can adjust screen condition by each OSD
function. The data of the adjust screen condition is
stored automatically.
7. Horizontal and Vertical Synchronous Processor
This circuit generates the horizontal drive pulse and
the vertical drive pulse by taking sync-signal form the
D-SUB (P208). This circuit consists of the TDA4856
(IC201) and the associated circuit.
8. Oscillating Circuit for D/D Converter.
This circuit generates the saw-tooth wave which has
the horizontal period by taking the output of the
TDA4856 (IC201).
9. D/D (DC to DC) Converter.
This circuit supplies DC voltage to the horizontal
deflection output circuit by decreasing DC 210V
which is the secondary voltage of the SMPS in
accordance with the input horizontal sync signal.
10. Side-Pincushion Correcting Circuit.
This circuit improves the side-pincushion of the screen
by mixing east-west wave to the output of the
horizontal deflection D/D converter which is used for
the supply voltage source (B+) of the deflection
circuit.
11. D/D Drive & Convert Circuit.
This circuit is used for supplying B+ voltage to
horizontal deflection output transistor(Q705). This
circuit makes to add side-pincushion correcting signal
to B+ voltage.
12. Horizontal Deflection Output Circuit.
This circuit makes the horizontal deflection by
supplying the saw-tooth current to the horizontal
deflection yoke.
13. High Voltage Output & FBT (Fly Back Transformer).
The high voltage output circuit is used for generating
pulse wave to the primary coil of the FBT (Fly Back
Transformer (T501)). A boosted voltage (about 27kV)
appears at the secondary of the FBT and it is supplied
to the anode of the CRT. And there are another output
voltages such as the dynamic focus frequency.

- 15 -
14. H-Linearity Correction Circuit.
This circuit corrects the horizontal linearity for each
horizontal sync frequency.
15. Vertical Output Circuit.
This circuit takes the vertical ramp wave form the
TDA4856(IC201) and performs the vertical deflection
by supplying the saw-tooth wave current form the
TDA8177 (IC601) to the vertical deflection yoke.
16. Dynamic Focus Output circuit.
This circuit takes H and V parabola wave from the
TDA4856(IC201) and amplifies these waves to offer to
the FBT(T501).
17. H & V Blanking and Brightness Control.
This circuit eliminates the retrace line by supplying a
negative pulse to the G1 of the CRT. The brightness
control circuit is used to control of the screen
brightness by changing the DC level of G1.
18. Tilt (Image Rotation) Circuit.
This circuit corrects the tilt of the screen by supplying
the image rotation signal to the tilt coil which is
attached to the CRT near the deflection.
19. Static Convergence Control Circuit.
This circuit corrects the convergence of the screen by
supplying the convergence signal to the 4H(STC) coil
which is attached to the CRT near the deflection.
20. Moiré Reduction Circuit.
This circuit reduce interference between the periodical
display pattern and the CRT’s slot (or dot). The
positions of every other one dot video signal beams
(red, green and blue beam) are shifted finely, thus
reducing interference.
21. OSD Circuit.
This circuit is used for performing the OSD (On
Screen Display) function. When a user selects the
OSD Select/ Adjustment control, the adjustment status
displays on the screen.
22. Video Pre-Amp Circuit.
This circuit amplifies the analog video signal from 0-
0.7V to 0-4V. This circuit is operated by taking the
clamp, R, G, B drives, and contrast signals from the
Micom (IC271).
23. Video Output Amp Circuit.
This circuit amplifies the video signal which comes
from the video pre-amp circuit and amplified video
signal is applied to the CRT cathode.

ADJUSTMENT
- 16 -
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
(DEGAUSSING) 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 8.
2) Adjust C970 (+) voltage to 210±0.5V with VR951.
2. Adjustment for High-Voltage.
1) Display cross hatch pattern at Mode 8.
2) Adjust CDT Anode voltage to 27kV±500V with
VR501.
3. Adjustment for Factory Mode (Preset Mode).
1) Display cross hatch pattern at Mode 9.
2) Run alignment program for NB230A on the IBM
compatible PC.
3) EEPROM →MODE CLEAR→Y(Yes) command.
<Caution> Do not run this procedure unless the
EEPROM is changed. All data in EEPROM (mode data
and color data)will be erased.
4) COMMAND →PRESET START→Y(Yes) command.
5) DIST. ADJ. → FOS. ADJ command.
6) Adjust V-SIZE as arrow keys to 290
± 1mm.
7) Adjust V-POSITION as arrow keys to center of the
screen.
8) Adjust H-SIZE as arrow keys to 390
± 2mm.
9) Adjust H-POSITION as arrow keys to center of the
screen.
10) Adjust SIDE-PIN (Side-Pincushion) as arrow keys to
be the best condition.
11) Adjust TRAPEZOID as arrow keys to be the best
condition.
12) Adjust TILT as arrow keys to be the best condition.
14) Save of the Mode.
15) PRESET EXIT → Y (Yes) command.
4. Adjustment for White Balance and Luminance.
1) Set the White Balance Meter.
2) Press the (DEGAUSSING) on the OSD menu for
demagnetization of the CDT.
3) Display color 0,0 pattern at Mode 7.
4) Set Brightness and Contrast to max position.
5) COLOR ADJ. → BIAS ADJ. command of the
alignment program.
6) Check whether blue color or not at R-BIAS and G-
BIAS to min position and B-BIAS to 80 (decimal)
position at Sub-Bright to 80 (decimal). If it's not blue
color, the monitor must to be repaired.
7) Adjust Screen control on the FBT to 0.1±0.02FL of
the raster luminance.
8) Adjust B-Bias to 80(decimal) position.
9) Adjust R-BIAS and G-BIAS command to x=0.283±
0.006 and y=0.298±0.006 on the White Balance
Meter with PC arrow keys.
10) Adjust SUB-Brightness command to 0.5±0.1FL of
the raster luminance.
11) Display color 15,0 box pattern (70x70mm) at Mode 7.
12) Set Brightness and Contrast to Max position.
13) DRIVE ADJ command.
14) Set B-DRIVE to 210 (decimal) at DRIVE of the
alignment program.
15)
Adjust R-DRIVE and G-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.
16) Adjust SUB-CONTRAST command to 35±1FL of
the raster luminance.
17) Display color 15,0 full white patten at Mode 9.
18) Set Brightness and Contrast to Max position.
19) COLOR ADJ. → LUMINANCE → ABL command.
20) Adjust ABL to 30±2FL of the luminance.
21) Exit from the program.
5. Adjustment for Focus.
1) Display H character in full screen at Mode 9.
2) Adjust Focus control on the FBT that focus should be
the best condition.

- 17 -
TROUBLESHOOTING GUIDE
1. NO POWER
NO POWER
(POWER INDICATOR OFF)
TROUBLE IN
D901
TROUBLE IN
FUSE (F901)
TROUBLE IN
IC902
CHECK
FUSE OK?
CHECK
C905 (+) VOLTAGE?
(400VDC AT INPUT
VOLTAGE 220VAC)
NO
YES
YES
NO
CHECK
Q901 DRAIN
WAVEFORM (SQUARE
WAVE COMES OUT?)
YES

- 18 -
2. NO CHARACTER
CHECK
IC301 PIN 30 (12V),
PIN 2 (5V)?
CHECK
IC301 PIN 1, 3, 6 ?
CHECK
IC301 PIN 25, 27, 29 ?
TROUBLE IN
P301,
5V, 12V LINE
TROUBLE IN
PC SIGNAL,
SIGNAL CABLE, IC2231
TROUBLE IN
IC301
TROUBLE IN
CDT SOCKET
NO
YES
NO
NO
YES
YES
CHECK
R, G, B CATHODE
VOLTAGE?
TROUBLE IN
IC303
NO
YES
NO CHARACTER

- 19 -
3. NO RASTER
NO VIDEO
(POWER INDICATOR
GREEN or ORANGE)
CHECK
POWER INDICATOR
GREEN or ORANGE ?
CHECK
SCREEN CONTROL
KNOB OF FBT
CHECK
VOLTAGE AT
D960 CATHODE (90V)
D962 CATHODE (210V)
D951 CATHODE (28V)
D957 CATHODE (80V)
D959 CATHODE (-15V)
D958 CATHODE (15V)
IC952 OUT (12V)
?
CHECK
IC271(MICOM) PIN 5
(5V), IC201 PIN 16
(12V)?
ROTATE SCREEN
CONTROL KNOB TO
CLOCKWISE
TROUBLE IN
IC271 (MICOM),
IC201 (T/BASE), TDA4856
TROUBLE IN
SECONDARY CIRCUIT
OF T901, T902
TROUBLE IN PRIMARY
CIRCUIT OF T901, T902
TROUBLE IN
D-SUB & 5-BNC
SIGNAL CABLE
ORANGE
MIN.
(Counter-clockwise)
GREEN
OK
YES
NO
YES
NO

- 20 -
4. NO VERTICAL DEFLECTION
NO V-DEFLECTION
(ONE HORIZONTAL LINE)
CHECK
IC601 PIN 2 (15V) ?
CHECK
IC601 PIN 4
(-12V)?
TROUBLE IN
T901 PIN 18
TROUBLE IN
T901 PIN 17
TROUBLE IN
IC601, VERTICAL
OUTPUT CIRCUIT
NO
NO
YES
YES
CHECK
IC201 PIN 12
(SAWTOOTH WAVE)? TROUBLE IN
IC201
NO
YES