LG 177V User manual

COLOR MONITOR
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
MENU SELECT
MODEL: 177V
CHASSIS NO. : CA-109
FACTORY MODEL: CS778G

1. PICTURE TUBE
Size : 17 inch
DefIection Angle : 90°
Neck Diameter : 29.1 mm
Dot Pitch : 0.27 mm
Face Treatment : W-ARASC (Anti-Reflection and
Anti-Static Coating),
Anti-static coating
Low Radiation : TCO 99
2. SIGNAL
2-1. Horizontal & Vertical Sync
1) Input Voltage Level: Low=0~1.2V, High=2.5~5.5V
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
3 row 15-pin Connector (Attached)
2-4. Scanning Frequency
Horizontal : 30 ~ 72 kHz
Vertical : 50 ~ 160 Hz
3. POWER SUPPLY
3-1. Power Range
AC 100~240V (Free Voltage), 50/60Hz, 2.0A Max.
3-2. Power Consumption
4. DISPLAY AREA
4-1. Active Video Area :
• Max Image Size - 326.7 x 245.5 mm (12.86" x 9.67")
• Preset Image Size - 310 x 230 mm (12.20" x 9.06")
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 : 5,000 m
6. DIMENSIONS (with TILT/SWIVEL)
Width : 400.0 mm (15.74 inch)
Depth : 420.0 mm (16.53 inch)
Height : 395.0 mm (15.55 inch)
7. WEIGHT (with TILT/SWIVEL)
Net Weight : 14.4 kg (31.75 lbs.)
Gross Weight : 17.0 kg (37.48 lbs.)
CONTENTS
- 2 -
SPECIFICATIONS ................................................... 2
SAFETY PRECAUTIONS ........................................ 3
TIMING CHART ....................................................... 4
OPERATING INSTRUCTIONS ................................ 5
WIRING DIAGRAM ................................................. 6
DISASSEMBLY ....................................................... 7
BLOCK DIAGRAM ................................................... 8
DESCRIPTION OF BLOCK DIAGRAM.....................9
ADJUSTMENT ....................................................... 11
TROUBLESHOOTING GUIDE .............................. 13
EXPLODED VIEW...................................................23
REPLACEMENT PARTS LIST ............................... 25
PIN CONFIGURATION........................................... 30
SCHEMATIC DIAGRAM......................................... 32
PRINTED CIRCUIT BOARD................................... 34
SPECIFICATIONS
MODE
MAX
NORMAL (ON)
STAND-BY
SUSPEND
OFF
POWER CONSUMPTION
85 W
74 W
less than 8 W
less than 8 W
less than 5 W
LED COLOR
GREEN
GREEN
AMBER
AMBER

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 25.5kV. 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
MODE 2
—
31.469
31.778
25.422
6.356
3.813
1.907
0.636
—
59.9
16.683
15.253
1.430
0.064
1.049
0.318
640
x
480
60Hz
Yes
MODE 1
—
31.472
31.774
25.419
6.355
3.813
1.906
0.635
+
70.1
14.267
12.710
1.557
0.064
1.080
0.413
720
x
400
70Hz
Yes
MODE 3
—
37.50
26.667
20.317
6.349
2.032
3.810
0.508
—
75.0
13.333
12.800
0.533
0.080
0.427
0.027
640
x
480
75Hz
Yes
MODE 4
—
43.269
23.111
17.778
5.333
1.556
2.222
1.556
—
85.0
11.764
11.093
0.670
0.069
0.578
0.023
640
x
480
85Hz
Yes
MODE 5
+
46.875
21.333
16.162
5.172
1.616
3.232
0.323
+
75.0
13.333
12.800
0.533
0.064
0.448
0.021
800
x
600
75Hz
Yes
MODE 6
+
53.674
18.631
14.222
4.409
1.138
2.702
0.569
+
85.061
11.756
11.179
0.578
0.056
0.503
0.019
800
x
600
85Hz
Yes
MODE 7
+
60.023
16.660
13.003
3.657
1.219
2.235
0.203
+
75.0
13.328
12.795
0.533
0.050
0.466
0.017
1024
x
768
75Hz
Yes
MODE 8
+
68.677
14.561
10.836
3.725
1.016
2.201
0.508
+
84.997
11.765
11.183
0.582
0.044
0.524
0.015
1024
x
768
85Hz
Yes
MODE 9
+
63.981
15.630
11.852
3.777
1.037
2.296
0.444
+
60.02
16.661
16.005
0.657
0.047
0.594
0.016
1280
x
1024
60Hz
Yes
MODE 10
—
50.6
19.752
15.802
3.950
1.580
1.975
0.395
—
100.1
9.995
9.481
0.514
0.059
0.435
0.020
640
x
480
100Hz
Yes
MODE 11
+
63.0
15.876
11.848
4.028
1.185
2.370
0.474
+
99.5
10.05
9.526
0.524
0.048
0.460
0.016
800
x
600
100Hz
Yes
MARK
E
A
B
D
F
C
E
A
B
D
F
C
Sync Polarity
Frequency
Total Period
Video Active Time
Blanking Time
Sync Duration
Back Porch
Front Porch
Sync Polarity
Frequency
Total Period
Video Active Time
Blanking Time
Sync Duration
Back Porch
Front Porch
FACTORY PRESET MODE
<< Dot Clock (MHz), Horizontal Frequency (kHz), Vertical Frequency (Hz), Horizontal etc... (µs), Vertical etc... (ms) >>

- 5 -
OPERATING INSTRUCTIONS
MENU SELECT
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
Use this button to turn the monitor ON or 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 amber,
and if abnormal or damaging circuit turns out amber blink.
3. Select Button
Use this button to enter a selection in the on screen
display.
4. Button
Use these buttons to choose or adjust items in the on
screen display.
5. MENU Button
Use this button to enter or exit the on screen display.
MENU SELECT
4
5
1
2
3

WIRING DIAGRAM
- 6 -
P501
P201
P405
P301
P302
G2
P702
P701
T1
P402
P902
S+
S
Signal Cable
AC Socket
FBT

- 7 -
DISASSEMBLY
(a)
Back Cover
Cabinet
(b)
(c)
1
22
3
3
Tip
C
B
A
Tip Spec.
A(Width) : 5.0~15.0mm
B(Depth) : 0.6~0.9mm
C(Height) : 12.0mm
1. TILT/SWIVEL & BACK COVER REMOVAL
1) Set the monitor face downward.
2) Pull the latch (a), carefully remove the Tilt/Swivel by pulling it upward.
3) Pressing the latch (b), Back cover by pushing it upward.
4) Release the latch (c).
5) Slide the Back Cover away from the Front Cabinet of the monitor.
2. TOTAL CHASSIS ASSEMBLY REMOVAL
1) Set the monitor face downward.
2) Pressing the latch (a), Main Chassis
by pushing it upward.
(a)
(a’)
CDT
Please be careful, not to cut pattern.

BLOCK DIAGRAM
- 8 -
OSD
ON/OFF
SELECT
POWER
POWER INPUT
100~240VAC
(50/60Hz)
Line
Filter
Degaussing
Circuit
< OSD Control >
SMPS
TRANS
(T901)
SMPS
CONTROL
(IC901)
DPM
CONTROL
CIRCUIT
Voltage
Regulating
Circuit
80V
50V
15V
6.3V
TILT
Control
Circuit
6.3V
15V
E2PROM
(IC402)
H / V POSITION
BRIGHTNESS
CONTRAST
H / V SIZE
SPCC
TRAPEZOID
PIN BALANCE
PARALLELOGRAM
ROTATION
RECALL
DEGAUSS
COLOR CURVE
MOIRE
LANGUAGE
RESET
VIDEO LEVEL
OSD TIME
5V
OSD IC
(IC301)
MTV038-15
H-Sync Sig
V-Sync Sig
I2C DATA(SDA)
I2C CLOCK(SCL)
VIDEO
LM1269
PRE-AMP
(IC302)
Signal
Cable R
G
BVIDEO
LM2467
LM2480
CUT OFF IC
(IC304)
MAIN AMP
(IC303)
5V
5V
H/V Sync Processor
( IC701 )
TDA4857 V-OUT
( IC601)
TDA4866
H-OUT
( Q706)
H-Linearity
Correction
DC/DC Converter
X-RAY
Protection
Circuit
FBT
( T701 )
Dynamic
Focus
Circuit
Auto
Beam
Limit
Vertical Blanking,
Brightness Control
- 160V
40V
400V
STEP UP
15V
D/D Feed Back
15V
MICOM
(IC401) SCL / SDA
H/V Sync,
PWM Control
15V
5V 15V
80V
15V
50V
DY CDT
Heater ( 6.3V )
I2C
I2C
I2C
H/V
Sync
G1
Screen(G2)
Dynamic Focus
Static Focus
H.V
R/G/B
Drive/Contrast
Cut-Off
H-DRV
B-DRV
B+
15V
TILT
COIL
DEGAUSSING
COIL
I2C
Vout 1
Vout 2

DESCRIPTION OF BLOCK DIAGRAM
- 9 -
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 (D900) 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, D942, D951, D961, D962, D971) and operate
other circuit. (horizontal and vertical deflection, video
amplifier, ...etc.)
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 Q941 and Q951 becomes stand-
by or suspend mode. It’s power consumption is below 8W.
5. X-ray Protection.
If the high voltage of the FBT reaches up to 29kV (abnormal
state), IC401(MICOM) pin 35 Sensing from FBT directly.
Then MICOM control IC701 (Deflection controller) to stop
Horizontal drive pulse and stop Horizontal Deflection.
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 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).
7. Horizontal and Vertical Synchronous Processor.
This circuit generates the horizontal drive pulse and the
vertical drive pulse by taking sync-signal from the Signal-
Cable. This circuit consists of the TDA4857(IC701) and
the associated circuit.
8. 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.
9. 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.
10. Horizontal Deflection Output Circuit.
This circuit makes the horizontal deflection by supplying
the saw-tooth current to the horizontal deflection yoke.
11. High Voltage Output & FBT(Flyback Transformer).
The high voltage output circuit is used for generating pulse
wave to the primary coil of the FBT(Flyback Transformer) .
A boosted voltage(about 26KV) appears at the secondary
of the FBT and it is supplied to the anode of the CDT. And
there are another output voltages such as the dynamic
focus and the screen voltage(G2).
12. H-Linearity Correction Circuit.
This circuit corrects the horizontal linearity for each
horizontal sync frequency.
13. Vertical Output Circuit.
This circuit takes the vertical ramp wave from the
TDA4857(IC701) and performs the vertical deflection by
supplying the saw-tooth current from the TDA4866(IC601)
to the vertical deflection yoke.
14. Dynamic Focus Output Circuit.
This circuit takes the horizontal and the vertical parabola
waves from the TDA4857(IC701) and amplifies it to
maintain constant focus on center and corners in the
screen.

- 10 -
15. 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.
16. 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.
17. Moire Rdduction Circuit
This circuit reduce interference between the periodical
display pattern and the CDT’s mask.
The positions of every other one dot video signal
beams(red, green, and blue beam) are shifted finely, thus
reducing interference.
18. 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.
19. 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).
20. 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.

- 11 -
ADJUSTMENT
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 High-Voltage.
1) Display cross hatch pattern at Mode 8.
2) Adjust CDT Anode voltage to 25.5kV ± 0.3kV with
alignment program for high voltage.
2. Adjustment for Factory Mode (Preset Mode).
1) Display cross hatch pattern at Mode 1.
2) Run alignment program for CS778G on the IBM
compatible PC.
3) EEPROM → ALL 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. → CTRL PWM → TILT command.
Adjust TILT as arrow keys to be the best condition.
6) DIST. ADJ. → BALANCE command.
7) Adjust balance of Pin-Balance and Parallelogram
correction as arrow keys to be the best condition.
8) DIST. ADJ. → FOS. ADJ command.
9) Adjust H-POSITION as arrow keys to center of the
screen.
10) Adjust H-SIZE as arrow keys to 310 ± 2mm.
11) Adjust V-POSITION as arrow keys to center of the
screen.
12) Adjust V-SIZE as arrow keys to 230 ± 2mm.
13) Adjust SPCC(Side Pincushion) and TRAPEZOID as
arrow keys to be the best condition.
14) Save of the Mode.
15) Display from Mode 2 to Mode 11 and repeat above
from number 8) to 14).
16) COMMAND → PRESET EXIT → Y (Yes) command.
3. 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 8.
4) COLOR ADJ. → LUMINANCE command of the
alignment program.
5) Set Brightness and Contrast to max position.
6) COLOR ADJ. → BIAS ADJ. command of the
alignment program.
7) Set the data as belows.
R- BIAS : Min → 0
G- BIAS : Min → 0
B- BIAS : Data → 127(7F)
Sub-Brightness : Data → Max177(B1)
and adjust raster luminance to 0.4 ± 0.05FL with
FBT screen Volume. Here check whether blue color
or not if it’s not blue color, the monitor must be
repaired.
8) Adjust R-BIAS and G-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-Brightness command to 0.4 ± 0.1FL of
the raster luminance.
10) Display color 15,0 box pattern(70x70mm) at Mode 8.
11)DRIVE ADJ → No 1. command.
12)Set Sub-contrast to 127(7F) and B-DRIVE to 90(5A)
position at DRIVE of the alignment program.
13)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.
14)Adjust SUB-CONTRAST command to 50±2FL of the
color 15,0 box pattern (70x70mm) luminance at
Mode 8.

- 12 -
15)Save in COLOR 1.
16)Display color 15,0 full white patten at Mode 8.
17)COLOR ADJ. → LUMINANCE → ABL command.
18) Adjust ABL to 32 ± 1FL of the luminance.
19) Exit from the program.
4. Input EDID Data.
1) Display color 15,0 cross hatch pattern at Mode 8.
2) EDID →EDID INFO command.
3) Check EDID data information, if incorrect, you should
modify EDID data and saved.
4 EEPROM →WRITE EDID command and confirm
“EDID Write OK!!”message of monitor.
5) Exit from the alignment program.
6) Power switch OFF/ON for EDID data save.
5. Adjustment for Focus.
1) Display “mE”character in full screen at Mode 8.
(1024x768/85Hz)
2) Adjust two Focus control on the FBT that focus
should be the best condition.
6. Special PRESET Mode Adjustment Method with
OSD control.
Service man can adjust preset modes data easily by
OSD control key (select/Adjustment) on the monitor
without any jig or program.
★Be careful to remember the data before adjustment
because it can’t be recalled.
◆Following is Adjustment Item.
1) H/V size & H/V position
2) SHAPE (except Tilt)
3) Luminance box pattern (70x70mm)
→ SCO (Sub-Contrast)
4) Luminance Back-Raster
→ SBR(Sub-Brightness)
5) Luminance Full-White
→ ABL (Auto Beam Limit)
◆Adjustment Procedure.
1) Power on the monitor.
2) First pushing the “Down”key and then with keeping
the condition push the “power”key. A screen of
monitor blinks one time.
3) Check change of symbol (☆→ 󱀕) that displays on
left below in the OSD window.
4) Select adjustment item 1) and 2) adjust using select/
adjustment key for preset mode save.
5) Select “DEGAUSS”in the special menu for luminance
adjustment item 3), 4) and 5).
* Before the luminance adjustment, set the max
position for extermal BRIGHTNESS & CONTRAST
and white color balance must be color 9300K.
6) Select SCO, SBR and ABL, adjust at mode 8.
Following are adjustment procedures using set/
adjustment key.
①SBR(Sub-Brightness): Back-Raster → 0.4FL
②
SCO(Sub-Contrast):Window luminance → 50FL (Box pattern)
③ABL(Auto Beam Limit): Full White → 32FL
7) After adjustment, set power switch off → on and the
symbol (󱀕) of OSD window disappear.

TROUBLESHOOTING GUIDE
- 13 -
1. NO POWER
NO POWER
(POWER INDICATOR OFF)
TROUBLE IN
D900
TROUBLE IN FUSE
(F901)
TROUBLE IN
IC901
TROUBLE IN
D941, D942, D951,
D961, D962, D971
TROUBLE IN
Q903, 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 5
WAVEFORM
(SQUARE WAVE
COMES OUT?)
CHECK
D941, D942, D951, D961,
D962, D971
VOLTAGE?

- 14 -
2. NO CHARACTER
NO CHARACTER
CHECK
IC302
PIN 9(5V) ?
CHECK
IC302 PIN 5, 6, 7?
CHECK
IC302 PIN 20, 19, 18 ?
CHECK
IC303
PIN 1, 2, 3 ?
CHECK
IC303 PIN 4 (80V)
PIN 8 (12V) ?
TROUBLE IN
P302 5V LINE
TROUBLE IN
PC SIGNAL,
P301 SIGNAL CABLE
TROUBLE IN
IC302
TROUBLE IN
P302 PIN 15(80V),
PIN 14(15V)
TROUBLE IN IC303
NO
YES
NO
NO
YES
YES
YES
YES
NO
NO
CHECK
R, G, B CATHODE
VOLTAGE?
TROUBLE IN
R341~R343,
R331~R333, L311~L313,
D307~D312
TROUBLE IN
CRT SOCKET
YES
NO

- 15 -
3. NO RASTER
NO VIDEO
(POWER INDICATOR ON)
CHECK
POWER INDICATOR
GREEN or AMBER?
CHECK
D712 ANODE
(-157V)?
CHECK
G1VOLTAGE?
(-55V~-150V)
TROUBLE IN
D712
TROUBLE IN
Q799
DPM MODE
(NO H and/or V SYNC)
AMBER
NO
GREEN
YES
NO
CHECK
CDT HEAT
VOLTAGE? (6.3V)
TROUBLE IN
D941, Q942, Q941
YES
NO
TROUBLE IN
CDT
YES

- 16 -
4. NO HORIZONTAL DEFLECTION
NO H-DEFLECTION
(ONE VERTICAL LINE)
CHECK
Q706?
CHECK
B+ VOLTAGE
(50V)?
CHECK
T701(FBT) PIN 2
(31KHZ 60V,
69KHZ 140V) ?
CHECK
Q701 COLLECTOR
WAVEFORM?
TROUBLE IN
Q706
TROUBLE IN
50V LINE
TROUBLE IN
Q719, Q720, D710
TROUBLE IN
Q701
TROUBLE IN
T701, P701
NO
NO
YES
YES
YES
YES
NO
NO
0V T

- 17 -
5. TROUBLE IN H-LINEARITY
UNBALANCED OF H-LIN.
CHECK
IC401
PIN 5, 6, 7 ?
CHECK
Q711~Q716?
CHECK
L703?
TROUBLE IN
IC401 (MICOM)
TROUBLE IN
Q711 ~ Q716
TROUBLE IN
L703
TROUBLE IN
C722, C723, C726, C729
NO
NO
NO
YES
YES
YES Cs SIGNAL TABLE
HORIZONTAL
FREQUENCY(fH)
30kHz ≤Hf < 35kHz
35kHz ≤Hf < 39kHz
39kHz ≤Hf < 44kHz
44kHz ≤Hf <
48zkHz
48kHz ≤Hf < 52kHz
52kHz ≤Hf < 58kHz
58kHz ≤Hf < 62kHz
62kHz ≤Hf < 66kHz
Cs0
0
0
0
0
0
0
0
0
0
Cs1
0
0
1
1
1
1
1
1
1
Cs2
0
1
0
0
0
1
1
1
1
Cs3
0
0
0
1
1
0
0
1
1

- 18 -
6. NO VERTICAL DEFLECTION
NO V-DEFLECTION
(ONE HORIZONTAL LINE)
CHECK
IC601 PIN 3
(15V)?
CHECK
IC601 PIN 7
(40V)?
CHECK
IC701 PIN 12, 13?
TROUBLE IN
R603 15V LINE
TROUBLE IN
HIGH-VOLTAGE OUT
CIRCUIT(FBT),
D721, R606
TROUBLE IN
IC701
TROUBLE IN
IC601, V-CIRCUIT
NO
NO
YES
YES
YES
NO
3V

- 19 -
7. TROUBLE IN OSD
TROUBLE IN
OSD PERIPHERAL
CIRCUIT
NO OSD
TROUBLE IN
5V LINE
TROUBLE IN
IC601 PIN8 (V-FBP),
IC701 PIN1 (H-FBP)
TROUBLE IN
IC302, IC301
TROUBLE IN
IC301, IC302
NO
YES
DC 5V
YES
YES
YES
NO
NO
NO
Pin 5 5V
Pin 10
5V
H+V
5V
H+V
CHECK
IC301 B+
(5V) ?
CHECK
IC301 PIN 12
WAVEFORM ?
(ENTER BUTTON MUST BE PRESSED.)
CHECK
IC301 PIN 5, 10
WAVEFORM?
CHECK
IC301 PIN 13, 14, 15 ?

- 20 -
8. TROUBLE IN DPM
CHECK
IC401 (MICOM)
PIN 30, 31 (H/V INPUT)
SIGNAL?
CHECK
IC401 PIN 13
WAVEFORM?
CHECK
IC401 (MICOM)
PIN 2, 3 ?
CHECK
B+LINE
(6.3V,15V) ?
CHECK PC,
(PC IS NOT GOING INTO
DPM OFF MODE)
TROUBLE IN
X401
TROUBLE IN
IC401 (MICOM)
TROUBLE IN
Q941, Q942, Q951, Q952,
TROUBLE IN PC
OFF MODE FAILURE
INPUT H/V SYNC SIGNAL
H/V SYNC
(NO OFF MODE.)
NO
NO
NO
NO (DPMF: 0V)
DPM TABLE
Mode Item
NORMAL
STAND-BY
SUSPEND
OFF
DPMF
H
L
L
L
LED
GREEN
AMBER
AMBER
AMBER
DPMS
H
H
H
L
YES
YES
SEE DPM TABLE
YES
YES
5V
24MHz