AOC A20E221 Series User manual

AOC A20E221
S
SE ER RV VI IC CE E M MA AN NU UA AL L
LCD TV MONITOR
A20E221
SERIES
THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE
EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT
GUARANTEE THE ACCURACY OF THIS INFORMATION AFTER THE DATE OF PUBLICATION
AND DISCLAIMS RELIABILITY FOR CHANGES, ERRORS OR OMISSIONS.
MANUFACTURE DATE: June-10,-2005 Revision: A00

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TABLE OF CONTENTS
1. SPECIFICATIONS ….............................................................................…………...….. 3
1-1 GENERAL
SPECIFICATIONS …................................................…………....…. 3
1-2 LCD TV
DESCRIPTION ..................................................…………...………….. 4
1-3 INTERFACE
CONNECTOR ......................................................………….....…. 4
2. D-SUB PIN DISTRIBUTION.........................................................................……………...… 4
2-1 FACTORY PRESET DISPLAY
MODES……………………………………..…... 5
3. ADJUSTMENT...............................................................……………...…………………. 6
3-1 USE OF THE REMOTE
CONTROL................................................………….... 6
3-2 USE OF THE
MENUS .....................................................................………….... 7
3-2-1 BUTTON
CONTROL .................................................................…………... 7
3-2-2 TO USE THE MENUS………..………………………………………………… 7
4. TROUBLE SHOOTING
CHART................................................................…………..... 13
4-1 PANEL CONTROL CIRCUIT TROUBLE
SHOOTING…………………………… 14
4-2 MAIN BOARD POWER VCC TROUBLE
SHOOTING…………………………… 14
4-3 REMOTE CONTROL BLOCK TROUBLE
SHOOTING.…………………………. 15
4-4 KEY BOARD CONTROL BLOCK TROUBLE
SHOOTING……………………… 16
4-5 PC CONTROL BLOCK TROUBLE SHOOTING…………………………………. 17
4-6 AUDIO CONTROL BLOCK TROUBLE
SHOOTING...............................……… 18
4-7 VIDEO CONTROL BLOCK TROUBLE SHOOTING ........................................ 19
5. WHITE-BALANCE, LUMINANCE
ADJUSTMENT………………………………………... 20
6. SOFTWARE FLOW
CHART………………………………………………………………... 22
7. MECHANICAL OF CABINET FRONT DIS-
ASSEMBLY…………………………………. 25
8. PARTS LISTING OF CABINET (BOM)…………………………………………………... 27
9. PCB LAYOUT..…………………………………………...........................……………...… 54
9-1 MAIN BOARD PCB LAYOUT.…………………………………………………….. 54

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9-2 POWER BOARD PCB LAYOUT………………………………………………….. 55
10. BLOCK DIAGRAM ........................................................………………………………... 56
10-1 MAIN BOARD BLOCK DIAGRAM……………………………………………..… 56
10-2 POWER BOARD BLOCK DIAGRAM……………………………………..…….. 57
11. SCHEMATIC
DIAGRAM ….......................................................................…………….. 58
11-1 MAIN BOARD SCHEMATIC
DIAGRAM………………...………………………. 58
11-2 POWER BOARD SCHEMATIC
DIAGRAM…………...………………………… 72

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1. SPECIFICATIONS
1-1 GENERAL SPECIFICATIONS
Items Specification
Screen Size 20” TFT-LCD Panel
Aspect Ratio 4:3
Resolution 800 x 600 (SVGA)
Display Area (opening)
H x V 408mm x306mm
Pixel Pitch 0.51mm x 0.51mm
Display colors 16.7 million
Contrast Ratio 400:1
Brightness 500cd / m²
Viewing Angle 160°(Horizontal)/120°(Vertical)
Response Time 16ms
Lamp Type/Life 60000 hr
LCD Panel
Color Temperature Cool / Warm
TV Tuning System NTSC 181 Channel with Electronic PLL
Tuner
Sound System MTS / SAP
Closed Caption, V-chip Yes
TV
Function
Color Systems NTSC/PAL-M/PAL-N
AV1 RCA x 1 Audio L/R x 1
RCA x 1
AV2 S-Video x 1 Audio L/R x 1 (Share)
Video
Inputs
Component YPbPr x 1 Audio L/R x 1
Signal Input Analog: D-Sub 15 pin (detachable cable)
PnP compatibility DDC 2B
Input frequency Analog: FH: 31.5KHz to 49KHz
FV: 56Hz to 75Hz
Recommended Analog: 800 x 600 (75Hz)
PC Input
Input Audio Headphone Mini-jack for stereo (3.5ø)
Speaker (built-in): Two 5 watt speakers
Headphone Mini-jack for stereo (3.5ø)
Audio
Output Audio Output: L / R
Line Output (RCA L/R)
OSD language English / French / Spanish/Portuguese
Table Stand Included
Wall Mount VESA 100 x 100 mm
Power Supply AC100V~240V, 50/60Hz
Power Power Consumption <70W
Operating Temp. + 0°C ~ + 40°C
Storage Temp. - 25°C ~ + 60°C
Environment
Operating Humidity. 10 % ~ 85 %
Panel Tilt Forwards/Backwards/
Rotation -5° / +20° / ±30°
Dimension W x H x D (with stand) 696 x 443x 250 (mm)
Weight (net) Kg (w/o Accessories) 9 Kg
Accessories
Remote Controller, Batteries (x2), AC Power
Cord, D-sub Signal Cable,
3.5mm Audio Cable, User’s Manual
1-2 LCD TV DESCRIPTION

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The LCD TV will contain a main board (include audio), a switching power board (include an inverter board), an IR
board, a Headphone jack board and a function keyboard. The main board and power board will house the flat panel
to control logic I2C bus, DDC, brightness control logic for LCD panel, DC-DC conversion to supply the appropriate
power to the whole board and transmitting TTL level signals into LCD Module to drive the LCD display circuit.
The inverter board will drive the 6CCFLs (Cold Cathode Fluorescent Tube).
The function keyboard and Remote Control will provide the OSD control signal to the Main Board.
1-3 INTERFACE CONNECTOR
(A) Power Cord Connector.
(B) RF Signal Connector.
(C) Video (AV1, AV2, S-VIDEO, COMPONENT) / Audio Signal Connectors.
(D) PC D-sub 15 pin Connector.
(E) PC Audio Connector.
2. D-SUB PIN DISTRIBUTION
This procedure gives you instructions for installing and using the LCD TV display.
1. Position 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.
2. Connect the 15-pin 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:
PIN NO. DESCRIPTION PIN NO. DESCRIPTION
1. RED Video 9. No Pin
2. GREEN Video 10. Sync Ground
3. BLUE Video 11. Not Used
4. Not Used 12. Serial Data for DDC
5. Ground 13. HORIZ. SYNC
6. Ground-R 14. VERT. SYNC
7. Ground-G 15. Serial Clock for DDC
8. Ground-B
3. S-Video ( Y /C ): TV rear side : 4 pin Mini-DIN female
Component Video: TV rear side : RCA female(Red/Green/Blue)
TV: TV rear side : IEC type female
AV: TVrearside :RCAfemale(Yellow)
Audio: TV rear side : RCA female (Red / White )
PC Input audio: 3.5mm Stereo female
Audio Input for AV, S-Video, Component Video : RCA female ( Red / White )
Headphone 3.5mm female
Audio line Out ( to another speaker ) : RCA female ( Red / White )
4. 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 "ORANGE" when the display is on.
1
6
11 15
5
10

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5. 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.
6. This TV (with PC function) has power saving function following the VESA DPMS. Be sure to connect the signal
cable to the PC.
7. If your TV requires service, it must be returned with the power cord.
2-1 FACTORY PRESET DISPLAY MODE
VGA MODES
Horizontal Vertical
Resolution
Nominal
Frequency
(KHz)
Sync
Polarity
Nominal
Freq.
(Hz)
Sync
Polarity
720x400 31.5 N 70.1 P
640x480 31.5 N 59.9 N
640x480 37.9 N 72.8 N
640x480 37.5 N 75 N
800x600 37.9 P 60.3 P
800x600 48.1 P 72.2 P
800x600 46.9 P 75 P
3. ADJUSTMENT
3-1 USE OF THE REMOTE CONTROL

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SLEEP
With this key you can set a
time period after which the
TV should switch itself to
standby. Press the key
repeatedly to select the
number of minutes. The
counter runs from
0,30,60,90,120 minutes. The
timer begins to count down
from the number of minutes
selected after the display
has disappeared.
SWAP
Not Supported. (for
the model with this
function only)
3-2 USE OF THE MENUS
3-2-1 BUTTON CONTROL
POWER:
Press to turn on/off the TV. The
TV is never completely powered
off unless it is physically
unplugged.
0~9/100 Digit buttons
To select a TV channel.
CH
Press ▲or▼to brows
through the TV channels
which are not erased. To
view a blocked channel,
use the digit buttons to
access the channel and
enter your access code.
VOL
Press + or – to
adjust the volume.
PC
select your input
source to PC
PIP
Press this button to
display PC input and
other input on the
screen at same time.
MUTE
Temporarily interrupt
the sound or restore it.
DISPLAY
Press this button to
Display Channel
number on the right-top
MTS /SAP
Press this key to
activate Multichannel
Television Sound,
Stereo or Mono sound.
PRE-CH
To display the previously
selected TV channel.
TV/VIDEO
Select your input source:
press repeatedly to
select TV, AV1, AV2, S-
VIDEO or COMPONENT
mode, according to
where you connected
your external source.
 AV1/AV2 for a VCR
connected to the AV
connectors of the TV.
 S-VIDEO for a S-
Video VCR connected
to the S-VIDEO
connector of the TV.
 COMPONENT for a
DVD/DTV Set Top Box
or another component
video device
connected to Y, Pb, Pr
and to the AV AUDIO
inputs L and R.
CAPTION
Press this button to turn
Closed Caption on.
Be sure you have selected
Caption On in the Setup
menu.
MENU
Press repeatedly to
dis
p
la
y
OSD menu.
V-CHIP
Press this button to
setu
p
p
arental
SIZE
Not Supported. (for the
model with this function onl
y)
POP
Not Supported. (for
the model with this
function only)

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MENU POWER -VOL +SOURCE
MENU: Press to show the OSD menu and exit OSD menu at the TV.
VCH Λ: Press to perform select function and channel.
POWER: Press to turn on or off the TV.
Light is green when the power on,
Light is orange when the power off.
-VOL +:Press to confirm your function selection and adjustment.
SOURCE: Press to select your input source.
3-2-2 TO USE THE MENUS
1. Press the MENU button to display each menu
2. Use the cursor up/down to select a menu item.
3. Use the cursor left/right to enter a submenu or enable/disable the function.
4. Press the MENU button to exit the menu.
Main menu
Press the MENU button into the main OSD (On Screen Display). Adjust item include VIDEO ADJUST, AUDIO
ADJUST, CLOSED CAPTION, V-CHIP, SLEEP TIMER, SET UP and PC ADJUST.
Video Adjust
1. Contrast, Brightness and Saturation are adjusted from 0 to 100.
2. Tint is adjusted from 0 to 100.
3. Black Level is adjusted from 0 to 100.
4. Sharpness is adjusted from 0 to 10.
VCHΛ

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You can adjust picture contrast, brightness, color, tint and sharpness to the levels you prefer.
5. Reset is set up to default value.
.
When adjust any item sub-OSD will show up like this
Audio Adjust
1. Volume is adjusted from 0 to 100.
2. Bass and Treble are adjusted from 0 to 100.
3. W Head Phone (optional) is the function for wireless headphone enable or disable.
You can adjust audio Volume, Balance, Bass and Treble to the levels you prefer.
When adjust any item sub-OSD will show up like this.
CLOSED CAPTION
It’s allows you to read the dialog of television programs on the TV screen. Designed to help the hearing impaired, this
feature uses on screen “text boxes” to show dialogue and conversations while the TV program is in progress. Captions
will appear on the screen only during captioned broadcasts.

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Remark: the captions do not always use correct spelling and grammar.
Not all TV programs and product commercials are made for broadcast with Closed Caption information included. Refer
to your area’s TV program listings for the TV channels and times of closed Caption shows. The captioned programs are
usually noted in the TV listings with service Marks such as “CC”.
Caption Mode:
Dialogue (and descriptions) for the action on the captioned TV program shows on screen. Usually CH1 is the most used
channel. CH2 may be used for alternate languages if they are being transmitted.
Text Mode:
Often used for channel guide, schedules, bulletin board information for Closed Caption programs, news, weather
information or stock marker reports.
Not all Closed Caption modes are necessarily being use by a TV channel during the transmission of a Closed Caption
program.
V-CHIP SETUP
Select V-Chip on OSD then enter 4 digits of pin number.
 Initial pin number is “0000”.
 If you enter an incorrect pin number “Incorrect” message will be displayed.
It is the parental control function (V-chip). It is used to block program viewing based on the ratings by the broadcaster.
The default setting is to allow all programs to be viewed. Viewing can be blocked by the type of program and by the
categories chosen be blocked. It is also possible to block all program viewing for a time period.
A. There are two item could be defined. One is TV Guidelines another one is Movie Guidelines.
B. Setting up TV Guidelines
 Use Up/Down arrow buttons to move around the matrix and press Right arrow button to change the value
form “U” to “B” or ”B” to ”U”

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 U: Unblock
B: Block
C. Setting up Movie Guidelines
 Use Up/Down arrow buttons to move around the matrix and press Right arrow button to change the value
from “U” to ‘B” or “B” to “U”
D. CHANGE PIN (personal identification number) is needed for changing password to control V-chip setup.
Process as follows: 1)ENTER OLD PIN CODE 2)ENTER NEW PIN CODE 3)CONFIRM
NEW PIN by entering new pin one more time.
Sleep Timer
It is for set a time period after which the TV should switch itself to standby. The counter runs from 0 > 30 > 60 > 90 > 120
minutes.

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The timer begins to count down from the number of minutes selected after the display has disappeared.
Note: To view the remaining time, press the SLEEP button once. To cancel the sleep time, repeatedly press the SLEEP
button until… appears. If you turn the TV off after setting the sleep time, the setting will be erased. Set it again.
SETUP
1
1. Blue screen for when no video input screen will be blue or blank. If it’s ON, the screen will be in blue. If it’s OFF, the
screen will be blank. Pre-set is ON.
2. Language for different language OSD MENU includes English / French / Spanish/Portuguese. Pre-set is English.
3. AIR/CATV for different TV input solution, RF and cable.
4. CH Search is for auto memorizes all receiving channels of air TV or CATV programs.
5. CH DEL. /ADD is for add “>” or delete “<“ the current channel for memorizes.
6. RESET is set up to default value.
PC Adjust
1. Auto Adjust is the function auto-sizing for VGA input.
2. Contrast, Brightness, Focus, Clock, H-Position, V-Position and Color are the functions for PC adjustment.
-
-

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The color temp is for you to adjust the color temperature to one you prefer.

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4. TROUBLE SHOOTING CHART
4-1. Panel Control Circuit
No Display
Replace panel or FPC
cable to panel
Replace L118, C317
Check U300 crystal
X300 (12MHZ) Replace X300
Check 2.5V L301-L304
3.3V L305-L308 Replace components
if it has problem
Replace U300
OK
OK
OK
OK
NG
NG
NG
NG
Check CN101 pin 42-45
is 5V and signal on pin
35,37,39,40,25-28,30-
33,15-18,20-23,5-8,10-13
Check U300 Output to
CN101 relative circuit
and CN101 VCC at
Q300, Q301, L309 (5V)

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4-2. Main Board Power Circuit
4-3. Remote Control Block

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4-4. Key Board Control Block

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4-5. PC Control Block

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4-6. Audio Control Block

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4-7 Video Control Block
Note: 1. If Replace “MAIN-BOARD” , Please re-do “DDC-content” programmed & “WHITE-Balance”.
2. If Replace “ POWER-BOARD INVERTER” only, Please re-do “ WHITE-Balance”
3. Please re-install program before you do change any component.
5. White-Balance, Luminance adjustment