Acer AT3720A/3720B/3720 LCD TV

Service Guide

Service guide files and updates are available on the ACER/CSD web; for more information, please refer to http://csd.acer.com.tw

PRINTED IN TAIWAN

Revision History
Please refer to the table below for the updates made on Acer LCD TV AT3720A/3720B/3720 service guide.

Chapter

Updates

Copyright

Copyright 2006 by Acer Incorporated. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written permission of Acer Incorporated.

Disclaimer

The information in this guide is subject to change without notice. Acer Incorporated makes no representations or warranties, either expressed or implied, with respect to the contents hereof and specifically disclaims any warranties of merchantability or fitness for any particular purpose. Any Acer Incorporated software described in this manual is sold or licensed "as is". Should the programs prove defective following their purchase, the buyer (and not Acer Incorporated, its distributor, or its dealer) assumes the entire cost of all necessary servicing, repair, and any incidental or consequential damages resulting from any defect in the software.
Acer is a registered trademark of Acer Corporation. Other brand and product names are trademarks and/or registered trademarks of their respective holders.

Conventions

The following conventions are used in this manual: SCREEN MESSAGES NOTE Denotes actual messages that appear on screen. Gives bits and pieces of additional information related to the current topic. Alerts you to any damage that might result from doing or not doing specific actions. Gives precautionary measures to avoid possible hardware or software problems. Reminds you to do specific actions relevant to the accomplishment of procedures.

WARNING

CAUTION

IMPORTANT

Preface
Before using this information and the product it supports, please read the following general information. 1. This Service Guide provides you with all technical information relating to the BASIC CONFIGURATION decided for Acer's "global" product offering. To better fit local market requirements and enhance product competitiveness, your regional office MAY have decided to extend the functionality of a machine (e.g. add-on card, modem, or extra memory capability). These LOCALIZED FEATURES will NOT be covered in this generic service guide. In such cases, please contact your regional offices or the responsible personnel/channel to provide you with further technical details. Please note WHEN ORDERING FRU PARTS, that you should check the most up-to-date information available on your regional web or channel. If, for whatever reason, a part number change is made, it will not be noted in the printed Service Guide. For ACER-AUTHORIZED SERVICE PROVIDERS, your Acer office may have a DIFFERENT part number code to those given in the FRU list of this printed Service Guide. You MUST use the list provided by your regional Acer office to order FRU parts for repair and service of customer machines.

Chapter 1

System Specifications

Features

This LCD TV was designed with the user in mind. Here are just a few of its many features:

LCD Panel

Max. resolution: 1366x768 Display area: 37 inches diagonal Display color: 16.7 M colors (8 real bits per color) Life time: 60,000 hours Input Signal: 1-ch LVDS Contrast ratio: 1200:1 ( Typ ) Brightness: 500 cd/m2 ( Typ ) Response Time: AUO Typ. Gray to gray Tr=Tf=35ms Viewing angle: 176 ( L ) / 176 ( R ), 176 ( U ) / 176 ( D)

I/O Functions

RCA jack (YUV and CVBS) for YPbPr, YCbCr, video and audio 15 pin D-Sub for VGA 24 pin DVI / HDCP for DVI-D (optional) 19 pin HDMI connector (optional) DIN45325 (IEC169-2) Terminal for TV / CATV input 3.5 mm
Earphone jack for audio line input

Video Functions

Support PAL/NTSC/SECAM video format (for AT3720A) Support 480i/576i, 480p/576p, 1080i and 720p format Build in Dynamic adaptive smoothing filter Build in Dynamic temporal frame-filtering Noise Reduction Build in Dynamic motion and edge adaptive De-interlacing Film mode 3:2 and 2:2 pull down Screen display model 16:9 / 4:3 / panorama / zoon / PIP /POP

Mechanical

Dimensions (W x H x D mm): 944 x 692 x 261 Weight (kg/lbs.): 23.9/53.1 Wall-mounting holes 400mm x 200mm

Power Source

Input voltage: 100 ~ 240 V, 50 ~ 60 Hz Max. power consumption: 235W
Input current: 2.2A Standby consumption is under 5 Watts

Speaker

Internal speaker: 10 W * 2 stereo, volume adjustable Amplimfier: 10W * 2 stereo, volume adjustable

System Block Diagram

System Block and Wiring Diagram

INVERTER

I/O Board

POWER Module

MAIN Board

A-Tuner

AV 1 AV 2

Component1

Component2

SPEAKER

IR Receiver

Key Board

LCD Main Board Block Diagram

Board Layout

Cable Arrangement
No. Connector CN908 (Power Board) CN903 (Power Board) <-->CON15 (Main Board) CN904<-->CON11 CON6 (Main Board) -CN1(Button Board)-CN1 (IR Board) CON17 (Main Board) CON13 (Main Board) Cable Description Inverter Cable Audio Cable-Main board (audio) to power board Power Cable Button Board-IR Board (CN1)-Main Board (CN1) Cable LVDS Cable Speaker Cable

LCD TV Overview

A general introduction to Acer LCD TV ports, functions and indicators.
AT3720A/AT3720B/AT3720 Front panle view
The panel view below is for AT3720A/AT3720B/AT3720.
Item Power On/Off Menu key Channel up/down
Description Power on or off the LCD TV. Turn s the OSD menu On and OFF. Channel up: When the OSD is on, functions the same as the Up arrow. Channel down: When the OSD is on, functions the same as the Down arrow.

Volume +/-

Volume up: When the OSD is on, functions the same as the Right arrow. Volume down: When the OSD is on, functions the same as the Left arrow.

Input key

When is OSD is on, press this button to confirm selection.

T3720A Rear panel view

# 5 Power switch AC-in HDMI VGA-in DVI-d

Item 8 9

# PC Audio-in
Item AV-Audio L/R + COMPONENT 1/2 AV-Audio L/R + CVBS 1/2 Analog antenna

AT3720B Rear panel view

# 5 Power switch AC-in HDMI VGA-in PC Audio-in
Item Audio L/R + CVBS + COMPONENT Audio L/R + CVBS + COMPONENT 1/2 Audio L/R + CVBS 1/2 + S-Video Analog antenna

AT3720 Rear panel view

# Power switch AC-in HDMI VGA-in

Item 7 8

Item AV-Audio L/R + CVBS + COMPONENT SCART Analog antenna
AT3720A Remote controller

General Keys

No. 7 POWER DISPLAY MUTE
Item Press to turn your TV on/off.
Description Press to display input/channel information (dependent on input/source type). Press to toggle audio on and off. Press to select correct input mode. Press to set a time period after which the TV will switch itself to standby (15, 30, 45, 60, 90 or 120 minutes). Press to select the TV channel. Press to reture to the previous channel.

Input buttons (TV/AV/ COMPONENT/PC) SLEEP Number keys RECALL
ENTER MENU CC Directional keys/OK WIDE MTS e (Empowering Technology) VOL (+/-) CH (up/down) PIP/PBP/POP SWAP ACTIVE POSITION SIZE/MODE
Press to confirm channel number selection. Press to open or close the Menu. Press to select close caption and text service between CC1, CC2, CC3, CC4, Text1, Text2, Twxt3, Text4. N/A Press to toggle scaling mode between 4:3; 16:9, Panorama and Letterbox 1, 2, 3 modes. Press to switch the sound system between stereo, main and SAP. Information is displayed in the top right-hand corner. Press to activate Acer Empowering Technology. Press to increase or decrease the volume. Press to sequentially select the TV channel. Switch between PIP/PBP/POP modes. For PIP/PBP mode: Toggle between the primary and subscreens. Tobble between primary and subscreens. When in PIP mode: Change subscreen position. When in PIP mode: Change subscreen size. When in POP mode: Switch POP mode from 1+5 to 1+12.
AT3720B Remote controller
Description Press to display input/channel information (dependent on input/source type). Press to toggle audio on and off. Press to select correct input mode. Press to set a time period after which the TV will switch itself to standby (15, 30, 45, 60, 90 or 120 minutes). Press to select the TV channel. Press to return to the previous channel.
ENTER MENU TTX/MIX (TELETEXT/MIX) Directional keys/OK WIDE MPX e (Empowering Technology) VOL (+/-) CH (up/down) PIP/PBP/POP SWAP ACTIVE POSITION SIZE/MODE
Press to confirm channel number selection. Press to open or close the Menu. Press to return to the previous channel. N/A Press to toggle scaling mode between 4:3; 16:9, Panorama and Letterbox 1, 2, 3 modes. Press to select the sound input, displayed in the top right-hand corner (mono, stereo, bilingual). Press to activate Acer Empowering Technology. Press to increase or decrease the volume. Press to sequentially select the TV channel. Switch between PIP/PBP/POP modes. For PIP/PBP mode: Toggle between the primary and subscreens. Toggle between primary and subscreens. When in PIP mode: Change subscreen position. When in PIP mode: Change subscreen size. When in POP mode: Switch POP mode from 1+5 to 1+12.

Teletext

No. 7 INDEX SIZE SUBTITLE SUBPAGE HOLD REVEAL
Item Colour buttons (R/G/Y/B) Press to go to the index page.
Description Operates corresponding button on the teletext page. Press once to zoom teletext page to 2X. Press again to resume. Press to view subtitles on the screen. Press to access the teletexts subpages directly. Press to pause the current teletext page in multi-page viewing mode. Press to reveal hidden teletext information.

AT3720 Remote controller

No. 11 POWER DISPLAY MUTE
Description Press to display input/channel information (dependent on input/source type). Press to toggle audio on and off. Press to select correct input mode. Press to set a time period after which the TV will switch itself to standby (15, 30, 45, 60, 90 or 120 minutes). Press to select the TV channel. Press to return to the previous channel. Press to confirm channel number selection. Press to open or close the Menu. Press to return to the previous channel. N/A

*SCART-out only works with analog broadcasts.
Connecting a camera, camcorder, video am or headphones
Connect your camera or camcorder to the video/audio ports on the rear of the TV set as shown below.
Connecting a PC or notebook computer
To display PC output on your TV, connect your PC or notebook computer to the TV as shown below. For AT3720A:
NOTE: For VGA and DVI input, Acer recommends setting your PCs external monitor resolution to 1360 x 768 pixel @ 60 Hz. For AT3720B:
Selecting the input source
Once you have connected your antenna or external equipment to the TV, you need to select the correct input source. Press the corresponding button on the remote control to select the correct input source.

For AT3720A/AT3720B:

COMPONENT

No TV key AV key

Input Button Guide Toggle Analog TV (ATV) between input sources. Toggle AV1, AV2, AV3-CVBS* and HDMI between input sources. Toggle COMPONENT 1, COMPONENT2 and AV3-COMPONENT* between input sources. Toggle VGA between input sources.

COMPONENT key PC key

OSD navigation
Many of the advanced settings and adjustments are available through using the OSD (onscreen display) menus, as shown in the example screenshot below. Basic operations required to navigate these menus (Picture, Audio, Channel management, Options, Settings and Empowering) are described in this section.
Navigating the OSD with the remote control
NOTE: You can also interact with these menus using the front panel controls. Please see Front panel view section for AT3220A.

Icon or Display

Description
There are six main OSD menus. These are: Picture, Audio, Channel management, Options, Settings and Empowering. Use the following method to navigate these menus. 1 Press the MENU button on the remote control or the MENU button on the control panel.
Select your desired menu by using the up and down directional keys to switch betwee the six menus.
Use the directional keys to ineract with the menu. The up / down directions will scroll through the menu options, while left / right will adjust the different settings (for example, in the Picture menus, settings such as brightness, contrast, etc.) Press MENU to exit.

Adjusting the OSD settings
The OSD can be used for adjusting the settings of your LCD TV. Press the MENU key to open the OSD. You can use the OSD to adjust the picture quality, audio settings, channel settings, options, general settings, and Empowering Technology. For advanced settings, please refer to following page:
Adjusting the picture quality
Press the MENU key to bring up the OSD. Using the directional keys, select Picture from the OSD. Then navigate to the picture element you wish to adjust. Use the left or right keys to adjust the sliding scales. The Picture menu can be used to adjust the current Scenario mode, brightness, contrast, color, sharpness and other image-related qualities.
Adjusting the audio settings
Press the MENU key to bring up the OSD. Using the directional keys, select Audio from the onscreen display. Then navigate to the feature you wish to adjust. Use the left or right keys to adjust the sliding scale. Press OK to save. The Audio menu can also be used to adjust the treble, balance, sound effects and other important sound-related settings.
Adjusting the channel management
Press the MENU key to bring up the OSD. Using the directional keys, select Channel management from the OSD. Use the directional keys to navigate the menus. The Channel management menu can be used to set channel skipped, select TV system and scan channels automatically.

Adjusting other options

Press the MENU key to bring up the OSD. Using the directional keys, select Options from the OSD. Use the directional keys to navigate the menus. The Options menu can be used to select the picture aspect-ratio mode, set the sleep timer and other important options.

Adjusting the settings

3 Press the MENU key to bring up the OSD. Using the directional keys, select Settings from the OSD. Then navigate to the feature you wish to adjust. The Settings menu can be used to adjust the menu language and other important settings.
NOTE: The options available on the OSD may vary depending on the TV signal source.

Empowering Technology

Less than 2 seconds Default setting in different mode Set-up Empowering mode More than 2 seconds
The Empowering Key opens up the Acer Empowering Technology functions. In TV mode, the choice is between Scenario mode and Favorite channel.

Set-up Empowering mode

To change your Empowering Keys default setting:
Press and hold the Empowering Key for more than two seconds to open the menu.

More than 2 seconds

TV mode Empowering Key settings menu
Use the directional keys to navigate the menu and select the Empowering Technology icon.
Press MENU to exit. Now, when you press the Empowering Key, your chosen selection will be accessed.
Default setting in different Empowering mode
Scenario mode in TV (default setting)
Scenario mode has five preset viewing modes designed to give you the best picture quality when watching a particular kind of program. There are five pre-defined audio and video settings for optimal enjoyment of the following scenarios: Standard TV, Movie, Sport, Concert, Game, User.
Pressing the Empowering Key for less than two second will toggle between the different modes.

Mode Standard

Information Standard mode allows you to watch your favorite channels with sharp, brilliant imagery via adaptive brightness and contrast adjustments, and listen to clear-sounding audio. For comfortably enjoying movies at home, Movie mode displays dim scenes in clear detail; compensates for color; and smoothly presents motion images. This is accomplished through optimal Gamma correction plus saturation, brightness and contrast adjustments. Movie mode makes the most of high-definition movie soundtracks. Game mode carefully details the exquisite graphics of modern video games, providing lifelike entertainment while protecting your eyesight by adjusting brightness and contrast. What's more, Game mode provides a heightened audio experience. Sports mode is suited for outdoor sports programs, with accurate background depth and clear gradation between the bright, outdoor playing field and darker auditoriums. Sports mode also brilliantly enhances colors and presents swiftly moving pictures without residual images. All of this is achieved via specific Gamma corrections and saturation adjustments. Precise audio can be heard. Concert mode places you in a virtual concert hall, opera house or other dim environment by means of adaptive brightness and contrast adjustments. Concert mode accentuates symphonic harmonies and the tenor audio range.

POP POP POP

PIP (Picture-in-Picture) PBP (Picture-by-Picture)

POP (Picture-on-Picture)

NOTE: The OSD menu is not available in PIP/POP/PBP modes.
1a. Press the ACTIVE key to toggle between PIP screens.
1b. Press the TV, AV, COMPONENT or PC keys, number keys or CH up or down to change the content of the active screen.
2. Press the SWAP key to change the content between the primary and the subscreen.
3. Press the POSITION key to select the location of the subscreens, from upper left -> upper right -> lower right -> lower left, as shown in the image.
4. Press the SIZE/MODE key to select the size of the subscreen, from 25% -> 37.5% -> 50%, as shown in the image.
1a. Press the ACTIVE key to toggle between PBP screens.
2. Press the SWAP key to change the content between the primary and the PBP screen.
1a. Press the ACTIVE key to toggle between POP screens.
1b. Press the number keys or CH up or down to change the TV channel on the active screen.
POP POP POP POP POP POP POP POP POP
POP POP POP POP POP POP POP POP
2. Press the SIZE/MODE key to access the 1 + 5 or 1+12 pictureon-picture mode as shown in the image.
NOTE: In PIP and PBP, the VGA and DVI sources only support input up to 1360x768 pixels at 60Hz. For resolutions higher than this, Out of Range will be displayed. NOTE: The POP can only support 1+12 when the main screen scurce is HD content or in VGA mode.

Lock TV

Locking TV content
Lock TV allows you to enter a password and effectively stop anyone without the password from watching TV.

to enable this feature:

Setting a personal PIN
Press the MENU key on the remote control to bring up the OSD.
Use the directional keys to navigate to the (see note)
Settings menu. Then select Set PIN.
Enter a four-digit password. Type it again and press OK to reconfirm.

Press MENU to exit.

Locking your TV
Use the directional keys to navigate to the
Settings menu. Then select Lock TV.
Enter your PIN. Type it again and press OK to reconfirm. (see page 16 note)
Hardware Specifications and Configurations

Electro / Optical

1. 2. 3. 4. 5. 6. 7.
Size of screen LCD panel supplier Screen aspect ratio Type of screen Screen resolution Display colors Chromaticity
37 inches for AT370A/AT3720B/AT3720 AUO TFT with Super MVA technology or SIPS or QSV 1366 x 768 16.7 M colors (8 real bits per color) Red Green Blue White Cold Middle-cold Standard Middle-warm Warm 0.638 0.271 0.145 0.275 16,000 degree K 14,000 degree K 12,000 degree K 10,000 degree K 8,000 degree K 0.335 0.597 0.065 0.298

Color temperature

Five models are adjustable,

White uniformity

N/A N/A 500 Cd/m2 (typical) 1200:1 (typical) N/A N/A Ultra wide viewing angle: 176 (H), 176 (V) (CR>20) N/A 8 ms (gray to gray) 60,000 Hours (Lamp is not included) 1-ch LVDS
10. White dispersion 11. Brightness 12. Contrast Ration 13. Uniformity 14. Overscan 15. Vision angle 16. Gamma 17. Response time (TR / TF) 18. Screen (lamp + LCD) life 19. Panel interface
Power supply electrical specification
The power supply for this product is an internal converter, with a non-replaceable fuse internally. This converter is designed to meet CE mark requirement.
Input voltage and frequency range:
The operating range of line voltage is AC 90 volts to 264 volts, 47Hz to 63 Hz. Input current: 2.2A

Line fuse:

The AC input is fused and becomes electrically open as a result of an unsafe current condition. This fuse is inside the power supply converter and is not use replaceable, and must be returned for replacement. This fuse is well selected to handle inrush current for all combinations of line voltage and frequency. 2. 3. 4.
Stand-by consumption Power consumption Mains disturbance behaviour
5 watts (max) 185 Watts No disjunction during 0 to 40ms mains interrupt, with max load, min mains voltage. No software reboot during the test. No over voltage causing any damage during mains interrupt (0 to any time). The inverter which is used to light up backlight of LCD panel is well designed to meet requirement of panel specification.

Inverter

Audio / Acoustical

Audio input

Level: 500 mVrms Type: Stereo R/L Channels Impedance: More than 22 K ohm Interface: RCA Jack, R: Red color, L: White color Level: 500 mVrms Type: Stereo R/L Channels Impedance: More than 22 K ohm Interface: 3.5mm stereo jack Max. audio output (at 10% THD max.) at 500 Vrms / 1KHz input: 8W + 8W Sound Distortion at 250 mW / KHz: 1% THD max. Speaker: 20W (10W + 10W) Speaker impedance: 4 ohm at 1KHz Residual Hum at Min. Volume: 500 uW Max. Max Hum at Max. Volume: 1000 uW Max. Audible noise in standby mode <35dBA (ISO-7779) Audible noise in power ON mode <35dBA (ISO-7779) Parasitic noise due to mechanical vibration during audio sweep must be inaudible at 1m around the TV.

PC Stereo Input

Built-in Speaker
acoustical noise (complete TV)

Hard / Soft Performance

1. 2. 3. 4.
Languages supported Starting time Wake-up behaviour Stand-by reason
Czech, Danish, Dutch, English, French, German, Italian, Polish, Portuguese, Russian, Spanish and Swedish A correct picture (color, aspect ratio, stability) can be displayed <6 second after power on The system can be waken up if the button Standby is pressed (keypad power or remote control power, 0 ~ 9, CH +/-). The TV pass in standby mode upon:

NOTE: PC & DVI only support 4/3 & 16/9

16. Scenario functions

Settings: Noise reduction:
Standard, movie, sport, concert, game, user Off, Low, Middle, High Volume, Balance, Bass, Treble, Mute, Mono / Stereo / Sound1 / Sound2
17. Audio management 18. Audio enhancement 19. AV sub-format
User adjustment: Stereo, SRS, WOW, BBE CVBS, YC, RGB, YUV HDCP (HDMI)

20. Copy protection

management
21. IR performance The reception distance indicates the distance between IR emitter and receptor which allow to recognize 85% or more IR frames. Reception distance: >7.5M perpendicular to the IR sensor >5M at 45o horizontally >5M at 45o vertically
Y axis 7.5M in front of the IR sensor

45 at 5m

X axis

Connectors

1. 2. 3. 4. 5. 6. 7. 8. 9.
Tuner type AV1 in AV2 in Component1 Component2
DVI-D HDMI PC D-sub in PC Audio in
Analog tuner in CVBS, S-video, Audio R/L CVBS, S-video, Audio R/L YCbCr/YPbPr, Audio R/L YCbCr/YPbPr, Audio R/L Yes (HDCP) 19 pins HDMI signal link (HDCP) Yes Yes
Environmental Requirements
The TV shall meet the following environmental requirements under normal operating conditions.

Operating

25o +/- 5o for purity, white point, mis-convergence, luminance measurements and white uniformity measurement Operating temperature: Operating humidity: 0oC to 35oC 10% to 90% (non-condensing) -20oC to 60oC -20oC to 60oC 10% to 90% (non-condensing) 10% to 90% (non-condensing) 0 to 12,000 feet 0 to 40,000 feet 0 to 40,000 feet

Storage and Shipping

Storage temperature: Shipping temperature: Storage humidity: Shipping temperature: Operating altitude: Shipping altitude: Storage altitude:

Altitude

Units tested at an altitude up to 12,000 feet must operate at normal conditions without exhibiting abnormal behavior such as arcing or shutdown.

Transportation

Vibration Test
The packaged display shall be capable of passing sinusoidal vibration test as specified in follows. A. test condition as below:
B. The unit under test shall be run for a duration of 30 minute in each of following orientations. a. Top and bottom side (z axis) b. Left and right side (x axis) c. Front and rear side (y axis) The unit shall suffer no visible cosmetic damage and should operate no degradation indisplay quality after test. Additionally, prior to production and prior to implementation of any design or manufacturing change that might affect vibration performance, a minimum of 2 units shall be demonstrated to meet the requirements of specification.

Drop Test

The packaged display shall be capable of passing drop test as specified in following specification without any measurable degradation in performance or detectable mechanical or cosmetic damage. Filter: 330 Hz Dropping way: 1 corner, 3 edges, 6 flats Dropping height: see the table below

10. Remove the four screws holding the IO tuner board and detach the IO tuner board. 11. Remove the screw (highlighted in yellow) holding the LVDS cable and remove the cable. Then remove the four screws (highlighted in red) fastening the PCB holder. 12. Detach the PCB holder.
13. Remove the four screws fastening the left speaker. 14. Remove the four screws holding the right speaker.
15. Tear off the mylard cover the speaker cable and detach the speaker cable. 16. Take out the speaker cable from the clip and then take out the left and the right speaker.
17. Remove the three screws fastening the button board then disconnect the cable and remove the board. 18. Remove the two screws holding the IR board then disconnect the IR board cable and remove the IR board. 19. Remove the three screws holding the main board-keypad-I R board cable and remove the cable.
20. If you need to take out the entire LCD module from the front bezel, please remove the four screws holding the LCD module to the front bezel. 21. Remove two screws on the left as shown.
22. Remove two screws on the right as shown. 23. Remove another four screws fasteing the LCD moudle to the front bezel. 24. Then you can hold the LCD brackets and lift the entire LCD module then take it away.
25. If you need to detach the LCD brackets from the LCD module, please remove two screws as shown. 26. Remove two screws on as shown.
27. Remove two screws as shown. 28. Remove two screws as shown. 29. Then remove four screws holding the LCD brackets to the LCD.
30. Remove four screws holding the LCD brackets to the LCD. 31. Then detach the LCD brackets from the LCD.
32. Remove the three screws holding the inverter bracket. 33. Detach the inverter bracket carefully.
34. Disconnect the inverter cable and backlight cables from the inverter. 35. Remove the three screws fastening the inverter and remove the inverter.

Troubleshooting

Use the following procedure as a guide for Acer LCD TV AT3720A/AT3720B and AT3720 problems. NOTE: The diagnostic tests are intended to test this model. Non-Acer products, prototype cards, or modified options can give false errors and invalid system responses. 1. 2. 3. 4. Duplicate symptom and obtain the failing symptoms in as much detail as possible. Distinguish symptom. Verify the symptoms by attempting to re-create the failure by running the diagnostic test or by repeating the same operation. Disassemble and assemble the unit without any power sources. If any problem occurs, you can perform visual inspection before you fellow this chapters instructions. You can check the following: power cords are properly connected and secured; there are no obvious shorts or opens; there are no obviously burned or heated components; all components appear normal. 5. Use the following flow chart determine which part to be replaced.
NOTE: N.G. in the below figures means No Good.

AT3720A Troubleshooting Guideline

1. Can not power on

Power code Plug in?

Check Power code

LED Bright?
Replace Power board or Main board Or IO board or All cable

LED Bright Green color ?

Check Remote control and keypad ?

Replacement M/B

Replacement Remote control or IR board or Keypad board

LCD Panel can Display ?

Check panels all cable

Check M/B

Replacement Panel

Replacement Cable

Chapter 4

LCD no backligh

Inverter power Cable had Plug in
Change Inverter Power Cable
LCD Panel Backlight Bright ?

Replacement Power/B

no Replacement LCD Panel Inverter /B
LCD Panel Backlight Bight

Replacement Main/B

Remote controller does not have function
Remote Control have battery ?

Change Battery

IR Board Cable plug in
Check IR/B cable or Replacement IR/B Cable
Press Remote Menu Key OSD can Display ?

Replacement IR/B

Replacement M /B
Button key does not have function

Key Board Cable plug in

Check K/B cable or Replacement K/B Cable
Press Menu Key check have Function?

Replacement K/B Cable

RF no display

RF Cable plug in

Check RF cable or Replacement RF Cable

Replacement I/O board

RF Can Display
Component 1, 2 no display

Component Cable plug in?

Check Component cable or Replacement Component Cable

Replacement I /O Board

Component can display

Replacement M/B Board

AV1, AV2 no display

CVBS Cable plug in?

Check CVBS cable or Replacement CVBS Cable

CVBS cat display Can

Speaker does not have sound
Audio R/L source had plug IN?
Check Audio R/L source cable

AT3720A Exploded Diagram

AT3720A/AT3720B/AT3720 FRU List is not ready as the service guide released. We will add the FRU list as soon as possible.