AOC N27W551T Schematic

27’’ LCD TV AOC N27W551T

Service

Service

Service

31.5-60 kHz

TABLE OF CONTENTS

Description Page Description Page

Table Of Contents.......……..............................…........1

Revision List.…........................................……......2

1. Monitor Specification..............................………........3

2. Operating Instructions…………………….……….......4

2.1 The Use Of Remote Control..……………...................4

2.2 The Use Of Teletext……..........…...........…...........5

2.3 Front Panel Control Knobs.…............……...............6

2.4 OSD Operations .………........................…............7

2.5 How To Connect ……..............……………............15

3 Input/Output Specification…………..........................19

3.1 Input Signal Connector……..........................19

3.2 RGB Input Signal Timing …….....……......................20

4. Mechanical Instructions…………………..................21

5. Repair Flow Chart ……………………….……….....25

6. White Balance Luminance Adjustment….…........32

7.BOM List..…………………………....….…….....36

8. PCB Layout ………….……………………....….......65

SAFETY NOTICE

ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE HIMSELF WITH THE

CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING
ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFOMER FOR THIS UNIT WHEN SERVICING

8.1 Main Board.……….......................................65

8.2 Power Board……..……..............................67

8.3 Tuner Board…...................................70

8.4 Key Board …................….......................71

8.5 IR Board …................….......................71

8.6 DC-DC Board....…………...............................71

8.7 Headphone Board..…..…..........................72

9. Block Diagram.…….........................................73

9.1 Main Board.………………………………..….73

9.2 Power Board…..…....………………….......74

9.3 Exploded View..……….....................…..75

10. Schematic Diagram………………………...77

10.1 Main Board………..………………………..77

10.2 Power Board.....…...................................89

10.3 Tuner Board...…….......................................91

10.4 Key Board……………….………………….94

Horizontal Frequency

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27’’ LCD TV AOC N27W551T

Revision List

Version Release Date Revision Instructions TPV Model

A00 Jul-05-2006 Initial Release E276MTNBD4TENP

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27’’ LCD TV AOC N27W551T

1. Monitor Specifications

Items Specification

Panel Type 27” CMO V270B1-L01 panel

Driver Element a-si TFT active matrix

Aspect Ratio 16: 9

Pixel Number 1366 x 768

Active Display Area H x V 596.259mmx335.232mm

Pixel Pitch 0. 4365mm(H) x 0.4365mm(V)

LCD Panel

Contrast Ratio 1000:1 (type)

Brightness 550:1 (type)

Response Time 8ms

View Angle (CR≥20) H: 176/V: 176 (CR>20)

Display colors 16.7M colors (8-bits colors)

Video Inputs
Video system
Audio Output
OSD language (default)
Table Stand
Wall Mount

Power

Environment

Lamp Type/Life 60000 hr (type)

Color Temperature Cool / Warm

AV,CVBS, S-Video, Composite Video, SCART (RGB + Composite),HDMI

NTSC/PAL/SECAM

Audio Output: L / R Headphone Mini-jack for stereo (3.5ø)

English

Included

VESA 100 x 100 mm

Power Supply AC100V~240V, 50/60Hz

Power Consumption <140W

Operating Tem. + 0 °C ~ + 40 °C

Storage Tem. - 10 °C ~ + 50 °C

Operating humidity 10% ~ 85%

Storage humidity 5% ~ 85%

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27’’ LCD TV AOC N27W551T

2. Operations Instructions

2.1 The Use Of Remote Control

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27’’ LCD TV AOC N27W551T

2.2 The Use Of Teletext

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27’’ LCD TV AOC N27W551T

2.3 Front Panel Control Knobs

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27’’ LCD TV AOC N27W551T

2.4 OSD Operations

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

2.5 How To Connect

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

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27’’ LCD TV AOC N27W551T

3. Input/Output Specification

3.1 Input Signal connector

This procedure gives you instructions for installing and using the LCD TV display.
Lay the display on the desired operation and plug the power cord into a convenient AC outlet. Three-wire power cord
must be shielded and is provided as a safety precaution as it connects the chassis and cabinet to the electrical
conduct ground. If the AC outlet in your location does not have provisions for the grounded type plug, the installer
should attach the proper adapter to ensure a safe ground potential.

Connect the 15-pin D-SUB color display shielded signal cable to your signal system device and lock both screws on
the connector to ensure firm grounding. The connector information is as follow:

1

6

11 15

5

10

15 - Pin Color Display Signal Cable

Pin No. Description

1 Red Video

2 Green Video

3 Blue Video

4 Not Used

5 GROUND

6 Red Video Ground

7 Green Video Ground

8 Blue Video Ground

9 No Pin

10 Sync. Ground

11 Not Used

12 Serial Data for DDC

13 Horizontal Sync.

14 Vertical Sync.

15 Serial Clock for DDC

Apply power to the display by turning the power switch to the "ON" position and allow about ten seconds for Panel
warm-up. The Power-On indicator lights "GREEN" when the display is on.

With proper signals feed to the display, a pattern or data should appear on the screen, adjust the brightness and
contrast to the most pleasing display, or press auto-adjust to get the best picture-quality.

This TV (with PC function) has power saving function following the VESA DPMS. Be sure to connect the signal
cable to the PC.

If your TV requires service, it must be returned with the power cord.

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27’’ LCD TV AOC N27W551T

3.2 RGB Input Signal Timing

Vertical

Dots × Lines

720 × 400 70.1 31.5 NEG POS YES YES YES YES

640 × 480

800 X 600

1024 × 768 60.0 48.4 POS POS YES YES YES YES

1280 × 768 75.0 60.3 NEG POS YES YES YES YES

Frequency

(Hz)

59.9 31.5 NEG NEG YES YES YES YES

75.0 37.5 NEG NEG YES YES YES YES

75.0 46.9 POS POS YES YES YES YES

Horizontal

Frequency

(kHz)

Sync Polarity Presence Screen Mode

Horizontal Vertical Horizontal Vertical

Normal

(4:3)

FULL
(16:9)

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27’’ LCD TV AOC N27W551T

4. Mechanical Instructions

Step Figure Description

Lay the LCD-TV

Preparation

on a flat, soft and

clean surface.

Remove
the stand

Remove the four
screws on the
stand to remove
the stand.

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27’’ LCD TV AOC N27W551T

Remove the
seven screws

Remove
the back
cover

mark in red to
remove the back
cover.

Remove
the plate

Remove the
six screws to
remove the plate.

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27’’ LCD TV AOC N27W551T

Remove
the shield.

1.Remove the
twelve screws

Remove
the shield

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2.Push the shield
as the arrowhead
direction.

27’’ LCD TV AOC N27W551T

1.Remove the
five screws
marked in red to
remove the
power board.

Remove
power
board,
tuner board
and power
board

2. Remove the
eight screws
marked in red to
remove the main
board and tuner
board

3.Disconnect the
connector and
remove the tuner
board , power
board and main
board.

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27’’ LCD TV AOC N27W551T

Remove
the bezel

Remove
the main
frame

Remove the
fourteen screws
to remove bezel.

1.Remove the
eight screws to
remove main
frame.

The end

N/A

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27’’ LCD TV AOC N27W551T

5. Repair Flow Chart

5.1 No Power (No LED indicator)

Check power cord and board interface

OK

NG

Plug in power cord and interface

Check F901, BD901, D901, D902

OK

Check IC981, D928 (12V)

NG

Check the load

NG

Replace F901 or BD901 or D910 or D902

Replace IC981or D928

OK

Check Q924, IC924 (ON/OFF signal)

OK

Check IC941, Q941

OK

Check T951

OK

NG

NG

NG

Replace IC941, Q941

Replace T951

Replace Q924 or IC924

Check IC901, Q901

NG

Replace IC901 or Q901

OK

Check Q942, Q943

OK

Check IC927

NG

NG

Replace Q942 or Q943

Replace IC927

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27’’ LCD TV AOC N27W551T

5.2 Can not start (LED indicator yellow)

Check key board

NG

Repair the key board

OK

Check 5V_SB

OK

NG

Return to “5.1”

Check 3.3V_SB

OK

Check PWR_ON signal

NG

NG

Replace U701

Check Q704, Q705, Q706, Q709

Check U32, U21

NG

NG

Replace U32 or U21

Replace Q704 or Q705 or Q706 or Q709

OK

Check PFC circuit

OK

NG

Replace IC901 or Q901

Check I2C communication

Check Panel inverter board

NG

Replace panel

Check main board power supply

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27’’ LCD TV AOC N27W551T

5.3 No display (LED indicator green)

Check the source

OK

Check LVDS cable

NG

NG

Reset source

Reset LVDS cable

Check 24V power supply

OK

OK

NG

Return to “5.1”

Check main board power supply

OK

Check U21

OK

NG

Replace U21

Check I2C communication

OK

Check panel

NG

Replace panel

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27’’ LCD TV AOC N27W551T

5.4 Abnormal display

Check the source

OK

Check signal filter circuit

NG

NG

Reset source

Replace the filter or inductance

OK

RF signal Check TV system setup

OK

Check Tuner

OK

NG

Replace Tuner

AV, SCART1/2_CVBS signal

Check U3

NG

Replace U3

OK

Check U21, U20

S-video SCART2_Y/C signal

PC signal

NG

Replace U20

Check U11

NG

Replace U11

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