LG CA66 Schematic

SPECIFICATIONS

1. PICTURE TUBE

Size : 17 inch (Flat Square Tube)
DefIection Angle : 90¡
Neck Diameter : 29.1mm
Transmission : 46%
Dot Pitch : 0.28mm
Face Treatment : AR-ASC (Anti-Reflection and

Anti-Static Coating)

Low Radiation : MPR-II, TCO-95

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 ½

3) Video Color : R, G, B Analog

4) Signal Format : Refer to the Timing Chart

2-3. Signal Connector

15-pin D-Sub Connector

2-4. Scanning Frequency

Horizontal : 30 ~ 70kHz
Vertical : 50 ~ 160Hz

3. POWER SUPPLY

3-1. Power Range

AC 100~264V (Free Voltage), 50/60Hz, 2.0A Max.

3-2. Power Consumption

4. DISPLAY AREA

4-1. Active Video Area : 310 x 230 mm (12.20" x 9.06")

(Available for Full Screen)
4-2. Display Color : Full Colors
4-3. Display Resolution : 1280 x 1024 / 60Hz

(Non-Interlace)
4-4. Video Bandwidth : 110MHz

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 : 5,000m

6. DIMENSIONS (with TILT/SWIVEL)

Width : 512mm (20.16 inch)
Depth : 545mm (21.46 inch)
Height : 525mm (20.67 inch)

7. WEIGHT (with TILT/SWIVEL)

Net Weight : 15.90kg (35.06 lbs.)
Gross Weight : 19.00kg (41.89 lbs.)

- 2 -

MODE

NORMAL (ON)

STAND-BY

SUSPEND

OFF

FAULT

H/V SYNC

ON/ON

OFF/ON

ON/OFF

OFF/OFF

OUT OF RANGE

POWER CONSUMPTION

less than 105 W

less than 15 W

less than 15 W

less than 15 W

less than 5 W

LED COLOR

GREEN

ORANGE

ORANGE

ORANGE

- 4 -

VIDEO

SYNC

C

E

D

F

AB

TIMING CHART

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

+

46.88

21.33

16.16

5.17

0.32

1.62

3.23

+

75.01

13.331

12.798

0.533

0.021

0.064

0.448

800

x

600

75Hz

Yes

MODE 1

Ñ

37.50

26.67

20.32

6.35

0.51

2.03

3.81

Ñ

74.99

13.335

12.802

0.533

0.026

0.080

0.427

640

x

480

75Hz

Yes

MODE 3

+

53.68

18.63

14.22

4.41

0.57

1.14

2.70

+

85.07

11.775

11.178

0.577

0.018

0.056

0.503

800

x

600

85Hz

Yes

MODE 4

+

68.677

14.561

10.836

3.725

0.508

1.016

2.201

+

85.00

11.764

11.182

0.582

0.014

0.044

0.524

1024

x

768

85Hz

Yes

MODE 5

Ñ

31.47

31.78

25.42

6.36

0.64

3.81

1.91

+

70.08

14.269

12.712

1.557

0.414

0063

1.080

640

x

400

70Hz

Yes

MODE 6

Ñ

31.47

31.78

25.42

6.36

0.64

3.81

1.91

Ñ

59.94

16.684

15.254

1.430

0.318

0.063

1.049

640

x

480

59Hz

Yes

MODE 7

+

37.88

26.40

20.00

6.40

1.00

3.20

2.20

+

60.32

16.579

15.840

0.739

0.026

0.106

0.607

800

x

600

60Hz

Yes

MODE 8

Ñ

43.27

23.11

17.78

5.33

0.89

1.33

3.11

Ñ

85.01

11.763

11.093

0.670

0.023

0.069

0.578

640

x

480

85Hz

Yes

MODE 9

Ñ

49.75

20.10

14.52

5.58

0.55

1.12

3.91

Ñ

74.95

13.407

12.542

0.865

0.021

0.060

0.784

832

x

624

75Hz

Yes

MODE 10

+

60.02

16.66

13.00

3.66

0.20

1.22

2.24

+

75.03

13.328

12.795

0.533

0.017

0.050

0.466

1024

x

768

75Hz

Yes

MODE 11

+

63.98

15.63

11.85

3.78

0.44

1.04

2.30

+

60.02

16.661

16.005

0.656

0.015

0.047

0.594

1280

x

1024

60Hz

Yes

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~Mode 4: Basic Mode (Mode 5~Mode 11: Default Mode)

- 8 -

CONTROL LOCATIONS

MAIN

FBT

CONTROL

1

2

3

4

5

7

89

10

6

NO.

1

2

3

4

5

Ref. No.

SW207

SW205

SW206

SW204

SW202

NO.

6

7

8

9

10

Ref. No.

SW203

SW201

VR101

VR701

VR901

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

TCO ADJUSTMENT

HIGH-VOLTAGE ADJUSTMENT

B+ADJUSTMENT

- 9 -

WIRING DIAGRAM

P201

P401

P102

P101

P501

WG2

P301P302

P702

P402

P902 P903

S

+

S

P304

P303

P704

P703

Signal
Cable

AC
Socket

FBT

- 10 -

DISASSEMBLY

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

P701

P102

DY Assembly Screw

P704

P304

P101

P401

P501

P902, P903

(c)

(b)

(b)

(c)

(a)

3. TOTAL CHASSIS ASSEMBLY REMOVAL

1)

Remove connector (a) from the DY Assembly screw.

2) Disconnect P304 (GND Wire) and two 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, P903
(Degaussing pin),
P701 (DY pin), P101, P102,
P401, P501, and P704
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 -

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, and P303
from the Video PCB.

2) Remove three screws (a).

3) Remove the Video PCB Assembly
from the Interface Assembly.

(a)

(a)

(a)

6. BOTTOM BRACKET REMOVAL

1) Remove three screws (a).

2) Remove five screws (b).

3) Remove the Bottom Bracket.

(b)

(b)

(a)

(a)

(b)

(b)

(a)

P303

P301

(b)

P302

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

160V
125V
70V
15V
12V

6.3V
5V

TILT
Control
Circuit

6.3V

6.3V

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
(IC303)

H-Sync Sig
V-Sync Sig

I2C DATA(SDA)

I2C CLOCK(SCL)

VIDEO
PRE-AMP
(IC302)

Signal
Cable

R
G
B

VIDEO
MAIN AMP
(IC303)

8V REG.

(IC304)

8V

12V

CUT OFF
CONTROL

125V

8V

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 )

Dynamic

Focus
Circuit

Auto
Beam
Limit

Vertical Blanking,

Brightness Control

- 120V

40V

6.3V

D/D Feed Back

30V

15V

MICOM
(IC401)

SCL / SDA

H/V Sync,

PWM Control

Sig

12V

15V

160V

DY CDT

Heater ( 6.3V )

I2C

I2C

I2C

H/V

Sync

G
1

Screen

Dynamic Focus

Static Focus

H.V

R/G/B

Bias

R/G/B

Contrast

H-DRV

B-DRV

B+

15V

POWER

TILT

COIL

DEGAUSSING

COIL

I2C

VOLTAGE

FEEDBACK

12V

DESCRIPTION OF BLOCK DIAGRAM

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 (C907).

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(D902, D922~D924, D926)) 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 11 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. Oscillating Circuit for D/D Converter.

This circuit generates the saw-tooth wave which has the
horizontal period by taking output of the TDA4856(IC701).

8. D/D(DC to DC) Converter.

This circuit supplies DC voltage to the horizontal
deflection output circuit by decreasing DC 160V 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 to the primary coil of the FBT(Flyback Transformer
(T701)). A boosted voltage(about 26kV) appears at the
secondary of the FBT and it is supplied to the anode,
focus, and screen voltage of the CRT.

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
TDA4856(IC701) and performs the vertical deflection by
supplying the saw-tooth current to the vertical deflection
yoke.

14. Dynamic Focus Output Circuit.

This circuit takes the horizontal and the vertical parabola
waves from the TDA4856(IC701) and amplifies it to
maintain constant focus on center and corners in the
screen.

- 13 -

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. 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).

18. 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.

- 14 -

- 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 4.

2) Adjust voltage to 160V

±

0.5Vdc with VR901.

2. Adjustment for High-Voltage.

1) Display cross hatch pattern at Mode 4.

2) Adjust FBT B+voltage to 140V

±

0.5Vdc with

VR701.

3. Adjustment for Factory Mode (Preset Mode).

1) Display cross hatch pattern at Mode 1.

2) Run alignment program for StudioWorks 775N,
CB775 on the IBM compatible PC.

3) Power button of the monitor turn off

→ turn on.

4) COMMAND → START → Y(Yes) command.

5) DIST. ADJ. → 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) Set Brightness and SUB-Brightness to Max position.

4) Display color 0,0 pattern at Mode 4.

5) COLOR ADJ. → LUMINANCE command of the

alignment program.

6) COLOR ADJ. → BIAS ADJ. command of the

alignment program.

7) Check whether blue color or not at R-BIAS and G­BIAS to min position and B-BIAS to 0.3

±

0.05FL.

Check it's not blue color.

8) Adjust R-BIAS and G-BIAS command to x=0.281

±

0.01 and y=0.311±0.01 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 4.

11)

Set Contrast and SUB-Contrast to max position.

12)

DRIVE ADJ command.

13)

Set B-DRIVE to 2/3 150(96) (decimal) at DRIVE of
the alignment program.

14)

Adjust R-DRIVE and G-DRIVE command to white
balance x=0.281

±

0.003 and y=0.311±0.003 on the

White Balance Meter with PC arrow keys.

ADJUSTMENT

- 16 -

Figure 1. Cable Connection

15)

Adjust SUB-CONTRAST command to 47±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 4.

17)

COLOR ADJ. → LUMINANCE → ABL command.

18)

Adjust ABL to 31±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 4.

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

15

10

5

5

69

1

1

1

14

13

25

6

5V

5V

5V

4.7K

4.7K

4.7K

74LS06

74LS06

OFF ON

OFF

ON

11

NO POWER

(POWER INDICATOR

OFF)

TROUBLE IN
D901, D902, D903, D904

TROUBLE IN FUSE
(F901)

TROUBLE IN
IC901, IC902

TROUBLE IN
D920, D922, D923,
D924, D926

TROUBLE IN

IC923, IC925, Q922,

Q923, Q924, Q926

CHECK

FUSE OK?

CHECK

C907 VOLTAGE?

(AC120V: 170VDC,

AC220V: 310VDC)

NO

YES

YES

YES

YES

NO

NO

NO

- 17 -

CHECK

IC901 PIN 3

WAVEFORM

(SQUARE WAVE

COMES OUT?)

CHECK

D920, D922, D924,

D923, D926
VOLTAGE?

TROUBLESHOOTING GUIDE

1. NO POWER

2. NO CHARACTER

- 18 -

NO CHARACTER

CHECK

IC302 PIN 7, 15, 18,

21(8V) ?

CHECK

IC302 PIN 6, 8, 10 ?

CHECK

IC302 PIN 16, 19, 22 ?

CHECK

IC303

PIN 1, 3, 5 ?

CHECK

IC303 PIN 6 (70V)

10 (12V) ?

TROUBLE IN
P302 12V LINE, IC304

TROUBLE IN
PC SIGNAL,
P301 SIGNAL CABLE

TROUBLE IN
IC302

TROUBLE IN
P302 12V LINE/70V LINE

TROUBLE IN IC303

NO

YES

NO

NO

YES

YES

YES

YES

NO

NO

CHECK

R, G, B CATHODE

VOLTAGE?

TROUBLE IN
R338~R341,
R344, R345, L302~L304,
D307~D310, D312, D313

TROUBLE IN

CRT SOCKET

YES

NO

NO VIDEO

(POWER INDICATOR ON)

CHECK

POWER INDICATOR

GREEN or ORANGE?

CHECK

D712 ANODE

(-120V)?

CHECK

G1 VOLTAGE?

(

10~20V)

TROUBLE IN
D712

TROUBLE IN

D926, Q925 (6.3V)

TROUBLE IN
Q801~Q806

DPM MODE
(NO H and/or V SYNC)

ORANGE

NO

GREEN

YES

YES

NO

- 19 -

3. NO RASTER