LG F720PK, F720P Service Manual [ENG]

COLOR MONIT OR

SER VICE 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: F720P (F720PK-AL**Q)

CHASSIS NO. : CA-127

( ) **Same model for SVC

*Same looking with new chassis.

Issue Date; 2003. 12.

1. PICTURE TUBE

Size : 17 inch
DefIection Angle : 90°
Neck Diameter : 29.1 mm
Diagonal inch : 16”
Slot Pitch : 0.24 mm
Face Treatment : W-ARASC (Anti-Reflective and

Anti-Static Coating),
Internal Anti-Glare

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 Connector

2-4. Scanning Frequency

Horizontal : 30~98 kHz
Vertical : 50~160 Hz

3. POWER SUPPLY

AC 100~240V, 50/60HZ, 2.5A Max
AC 200~240V, 50Hz, 1.5A Max.(PFC version)

3-2. Power Consumption

4. DISPLAY AREA

4-1. Active Video Area :

• Max Image Size - 325.4 x 244.1mm (12.91" x 9.61")

• Preset Image Size - 310 x 230 mm (12.20" x 9.06")
4-2. Display Color : Full Colors
4-3. Display Resolution : 1600 Dots x 1200Lines
4-4. Video Bandwidth : 203MHz

5. ENVIRONMENT

5-1. Operating Temperature: 0°C~40°C (32°F~103°F)

(Ambient)

5-2. Relative Humidity : 10%~90%

(Non-condensing)

5-3. Altitude : Less Than 16,404ft

6. DIMENSIONS (with TILT/SWIVEL)

Width : 415.0 mm (16.34")
Depth : 432.0 mm (17.00")
Height : 413.0 mm (16.25")

7. WEIGHT (with TILT/SWIVEL)

Net Weight : 16.5 kg (36.38lbs)
Gross Weight : 19.5 kg (42.99lbs)

8. USB Specifications

USB Standard :

Rev. 1.0 complied bus-powered hub

Downstream power supply

: 100mA 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 ......................................... 7

WIRING DIAGRAM ................................................. 8

DISASSEMBLY ....................................................... 9

BLOCK DIAGRAM ................................................. 10

DESCRIPTION OF BLOCK DIAGRAM................... 11

ADJUSTMENT ...................................................... 13

TROUBLESHOOTING GUIDE .............................. 15

EXPLODED VIEW.................................................. 21

REPLACEMENT PARTS LIST .............................. 23

PIN CONFIGURATION .......................................... 30

SCHEMATIC DIAGRAM......................................... 31

PRINTED CIRCUIT BOARD................................... 33

MODE

MAX

NORMAL (ON)

STAND-BY
SUSPEND

POWER OFF

H/V SYNC

ON/ON
OFF/ON
ON/OFF

POWER CONSUMPTION

less than 110W
less than 83W
less than 8W
less than 8W
less than 1W OFF

LED COLOR

GREEN/BLUE

GREEN/BLUE

ORANGE

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 26kV. The following steps describe
how to measure the high voltage and how to prevent X­radiation.

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

E

F

BC

kHz

µs
µs
µs
µs
µs
µs

Hz
ms
ms
ms
ms
ms
ms

MODE 1

–

43.269

23.112

17.778

5.334

1.556

1.556

2.222

–

85.008

11.763

11.093

0.670

0.023

0.069

0.578

640

X

480

85Hz

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

+

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

+

91.146

10.971

8.127

2.844

0.406

1.016

1.422
+

85.024

11.762

11.235

0.527

0.011

0.033

0.483

1280

X

1024
85Hz

Yes

MODE 5

+

93.750

10.666

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

MARK

A
B
C
D
E
F

A
B
C
D
E
F

MODE

FACTORY PRESET MODE

Resolution

Recall

H
O
R

I
Z
O
N
T
A
L

V
E
R
T

I
C
A
L

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

VESA

* Mode 5 is not preset mode but TCO check resolution!

- 5 -

See Front Control Panel

OPERATING INSTRUCTIONS

AC Power Socket

Power Button

Front Control Panel

REAR VIEW FRONT VIEW

D-Sub Signal Connector

1. Power 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. If the monitor is in stand-by,
suspend or DPMS off mode, this indicator color
changes to amber.

3. MENU (or OSD) Button

Use this button to enter or exit the on screen
display.

4

3

2

1

4. Button

Use these buttons to choose or adjust items in
the on screen display.

The Contrast and Brightness functions are also available in

the On Screen Display (OSD) menu.

5. SELECT (or SET) Button

Use this button to enter a selection in the on
screen display..

5

4

100

100

Button
Button

Bring up Contrast adjustment
Bring up Brightness adjustment

Universal Serial Bus

- 6 -

USB connection (Option)

(1) Connect the upstream port of the monitor to the downstream port of the USB
compliant PC or another hub using the USB cable.
(2) Connect the USB compliant peripherals to the downstream ports the monitor.

*USB(Universal Serial Bus) is supported WINDOWS98 and Higher.

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, printer, and other peripherals 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 2 other USB devices to
be attached it.

USB Downstream Ports

Connect the cables from USB compliant
peripherals-such as keyboard, mouse,
printer, scanner, etc.

USB Upstream Port

To USB downstream port
of the USB compliant PC
or another hub cable

USB Upstream connector USB Downstream connector

CONTROL LOCATIONS

- 7 -

VR 901

: B Adjustment (190V Line)

+

VR 801
: High Voltage Adjustment (26kV)

WIRING DIAGRAM

- 8 -

P301

P302

P303

Signal
Cable

AC
Socket

FBT

P801

S-

S+

P901

P702

P451

P902

P401

P201P250

P402

DISASSEMBLY

- 9 -

1. TILT/SWIVEL & BACK COVER REMOVAL

1) Set the monitor face downward.

2) Carefully remove the Tilt/Swivel by pulling it upward.

3) Pressing the latch (a), Back cover by pushing it upward. (See Figure. 1)

4) Release the latch (c). (See Figure. 2 and Tip Spec.)

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.

Back Cover

Cabinet

(b)

Tip Spec.

A(Width) : 5.0~15.0mm
B(Depth) : 0.6~0.9mm
C(Height) : 12.0mm

Figure. 1

Figure. 2

(a)

(a)

CDT

(a)

C

Tip

B

A

BLOCK DIAGRAM

- 10 -

SIGNAL

INPUT