How it Works
AOC
Loading...
LM923
Schematic
55 pgs3.68 Mb0
User Manual
20 pgs258.99 Kb0

AOC LM923 Schematic

AOC LM923
SERVICE MANUAL
19” LCD MONITOR
LM923
http://www.wjel.net
THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE EFFORT HAS
THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS RELIABILITY FOR CHANGES,
ERRORS OR OMISSIONS.
Page 1 of 55
AOC LM923
Table of Content
Revision List…………………………………………………………………………………………………………. 3
1. Monitor Specifications………………………………………………………………………………………….. 4
2. LCD Monitor Description……………………………………………………………………………………….. 5
3. Operating Instructions………………………………………………………………………………………….. 6
3.1 General Instructions…………………………………………………………………………………………... 6
3.2 Control Buttons………………………………………………………………………………………………... 6
3.3 Adjusting the Picture………………………………………………………………………………………….. 7
4. Input/Output Specification……………………………………………………………………………………... 9
4.1 Input Signal Connector……………………………………………………………………………………….. 9
4.2 Factory Preset Display Modes……………………………………………………………………………….. 10
4.3 Power Supply Requirements………………………………………………………………………………… 10
4.4 Panel Specification………………………………………………………………………………………….… 11
4.4.1Display Characteristics………………………………………………………………………………… 11
4.4.2Optical Characteristics…………………………………………………………………………………… 11
4.4.3 Parameter Guide Line For CCFL Inverter……………………………………………………………… 12
5. Block Diagram………………………………………………………………………………………………….… 13
5.1 Monitor Exploded View……………………………………………………………………………………….. 13
5.2 Software Flow Chart…………………………………………………………………………………………... 14
5.3 Electrical Block Diagram……………………………………………………………………………………… 16
5.3.1 Main Board………………………………………………………………………………………………... 16
5.3.2 Inverter/Power Board………………………………………………………….…………………………. 17
6. Schematic……………………………………………………………………………………………………….… 18
6.1 Main Board…………………………………………………………………………………………………….. 18
6.2 Audio Board……………………………………………………………………….………………………….. 24
6.3 Power Board……………………………………………………………………….………………………….. 25
7. PCB Layout………………………………………………………………………………………………………. 28
7.1 Main Board…………………………………………………………………………………………………….. 28
7.2 Audio Board…………………………………………………………….……………………………………… 29
7.3 Power Board………………………………………………………………………….……………………….. 30
7.4 Key Board……………………………………………………………………………………………………… 30
http://www.wjel.net
8. Maintainability……………………………………………………………………………………………………. 31
8.1 Equipments and Tools Requirement………………………………………………………………………… 31
8.2 Trouble Shooting…………………………………………………………………………………………….… 32
8.2.1 Main Board………………………………………………………………………………………………... 32
8.2.2 Power /Inverter/Board……………………………………………………………………………………. 35
8.2.3 Keypad Board…………………………………………………………………………………………….. 37
9. White-Balance, Luminance adjustment………………………………………………………………….… 38
10. EDID Content……………………………………………………………………………………………………. 39
11. BOM List………………………………………………………………………………………………………... 40
Page 2 of 55
AOC LM923
REVISION LIST
Revision Date Revision History TPV Model
A00 Nov-28-05 First Version Release T980KAXHLFMRA
http://www.wjel.net
Page 3 of 55
1.MONITOR SPECIFICATIONS
ITEMS SPECIFICATIONS
Driving system TFT LCD
LCD Panel
Pixel pitch 0.294mm( H )x 0.294mm( V )
Viewable angle 170˚ (H) 170˚ (V)
Response time (type) 25 ms for AU panel
Sync. Type H/V TTL
AOC LM923
Size 48.0cm(19.0")
Type M190EN02
Input
Dot Clock 135MHz
Contrast Ratio 700:1
White Luminance 250cd/m
Max. Resolution 1280 x 1024
Plug & Play VESA DDC2BTM
Power Consumption
Power Source 100~240VAC,47~63Hz
Display Color 16.7M colors (RGB 8-bits data)
Maximum Screen Size
H-Frequency 30kHz – 83kHz
V-Frequency 55-75Hz
2
ON Mode<55W
OFF Mode<
Horizontal : 376.32mm
Vertical: 301.056mm
2W
Environmental
Considerations
http://www.wjel.net
Operating Temp: 0°C to 40°C
Storage Temp: -20°C to 60°C
Operating Humidity: 15% to 90%
Page 4 of 55
AOC LM923
(
)
2. LCD MONITOR DESCRIPTION
The LCD MONITOR will contain a main board, a power board, a keypad board and an audio board which house the flat
panel control logic, brightness control logic and DDC.
The power board will provide AC to DC Inverter voltage to drive the backlight of panel and the main board chips each
voltage.
PWPC board
Include: adapter, inverter
AC-IN
100V-240V
Monitor Block Diagram
CCFL Drive.
Main Board
Audio board
Flat Panel and
CCFL backlight
Keyboard
RS232 Connector
For white balance
adjustment in factory
mode
Video signal,
HOST Computer
http://www.wjel.net
Page 5 of 55
AOC LM923
3. OPERATING INSTRUCTIONS
3.1 GENERAL INSTRUCTIONS
Press the power button to turn the monitor on or off. The other control buttons are located at front panel of the
monitor. By changing these settings, the picture can be adjusted to your personal preferences.
The power cord should be connected.
-
Connect the video cable from the monitor to the video card.
-
Press the power button to turn on the monitor, the power indicator will light up.
-
3.2 CONTROL BUTTONS
- Power Button:
When pressed, the monitor enters the off mode, and the LED turns blank. Press again to restore normal status.
- Left / Right Button: The Left/Right Button is used to control the monitor functions. Press to switch functions or adjust settings.
- Auto Adjust Key:
The Auto Adjust Key is used to automatically set the H Position, V Position, Clock and Phase.
- Power Indicator: Green — Power On mode. Orange — Power Saving mode. Blank —Power Off Mode.
O. Name
1 Auto/Exit Exit OSD or back to previous menu Auto configuration
2 Volume down/
3 Volume up /
4 MENU/ENTER Select Function or select Sub menu Activate OSD main menu
5 POWER Power On / Off Power On / Off
6 LED Green—On Orange—Save Green—On Orange—Save
http://www.wjel.net
1.Move the cursor to down
2.Decrease the value of the selected item
1.Move the cursor to up
2.Increase the value of the selected item
Within OSD
Page 6 of 55
Activate the volume menu
Activate the volume menu
Without OSD
AOC LM923
3.3 ADJUSTING THE PICTURE
Adjustment steps:
1. Press the MENU-button to activate the OSD window.
2. Press < or > to select the desired function.
3. Press the MENU-button to select the function that you want to adjust.
4. Press < or > to change the settings of the current function.
5. To exit and save, select the exit function, or leave the monitor alone for 10 seconds. If you want to adjust any
other function, repeat steps 2-4.
OSD TABLE:
Main Menu
Luminance
Image Setup
Image
Position
Item
Main Menu
Icon
http://www.wjel.net
Sub Menu Item Sub Menu Icon Description
Contrast
Brightness
Focus
Clock
H. Position
V. Position
Contrast from Digital-register.
Backlight Adjustment
Adjust Picture Phase to reduce
Horizontal-Line noise
Adjust picture Clock to reduce
Vertical-Line noise.
Adjust the horizontal position of
Adjust the vertical position of the
the picture.
picture.
Color Temp.
Warm N/A
Cool N/A
User / Red
User / Green
Page 7 of 55
Recall Warm Color Temperature
from EEPROM.
Recall Cool Color Temperature
from EEPROM.
Red Gain from Digital-register.
Green Gain Digital-register.
AOC LM923
User / Blue
Auto Config
(Analog-Only
Model)
OSD Setup
OSD Timeout
Language
Yes
No N/A
H. Position
V. Position
English N/A
Deutsch N/A
Français N/A
Español N/A
N/A
Blue Gain from Digital-register.
Auto Adjust the H/V Position,
Focus and Clock of picture.
Do not execute Auto Config,
return to main menu.
Adjust the horizontal position of
the OSD.
Adjust the vertical position of the
OSD.
Adjust the OSD timeout.
Set OSD display language to
English.
Set OSD display language to
German.
Set OSD display language to
French.
Set OSD display language to
Spain.
Set OSD display language to
Italian.
Set OSD display language to
Simplified Chinese.
Show the resolution, H/V
frequency and input port of current
input timing.
Clear each old status of
Auto-configuration and set the
color temperature to Cool.
Do not execute reset, return to
main menu.
Information
Reset
Exit
Italiano N/A
简体中文
http://www.wjel.net
Information N/A
Yes N /A
No N/A
N/A N/A Exit OSD
N/A
Page 8 of 55
4. INPUT/OUTPUT SPECIFICATION
4.1 INPUT SIGNAL CONNECTOR
PIN NO. DESCRIPTION PIN NO. DESCRIPTION
1. Red Video 9. +5V
AOC LM923
2. Green Video 10.
3. Blue Video 11.
4. Ground 12. DDC-Serial Data
5. Ground 13. H-Sync
6. Red Ground 14. V-Sync
7. Green Ground 15. DDC-Serial Clock
8. Blue Ground
VGA connector layout
15
6
11 15
10
Detect Cable
NC
http://www.wjel.net
Page 9 of 55
4.2 FACTORY PRESET DISPLAY MODES：
AOC LM923
STANDARD
Dos-mode 720 x 400 31.47kHz 70.0Hz
VGA
SVGA
XGA
SXGA
RESOLUTION
640 × 480 31.47kHz 60.0Hz
640 × 480 37.50kHz 75.0Hz
800 × 600 37.879kHz 60.0Hz
800 × 600 46.875kHz 75.0Hz
1024 × 768 48.363kHz 60.0Hz
1024 × 768 56.476kHz 70.0Hz
1024 × 768 60.021kHz 75.0Hz
1280 × 1024 64.000kHz 60.0Hz
1280 × 1024 80.000kHz 75.0Hz
4.3 POWER SUPPLY REQUIREMENTS
HORIZONTAL
FREQUENCY
VERTICAL
FREQUENCY
A/C Line voltage range 100 V ~ 240 V
A/C Line frequency range
Current 1.5A max at 100V; 0.8A max at 240 V
Peak surge current < 55A peak at 240 VAC and cold starting
Leakage current < 3.5mA
Power line surge
DC output Voltage
CURRENT
50 ± 3Hz, 60 ± 3Hz
No advance effects (no loss of information or defect)
with a maximum of 1 half-wave missing per second
5VDC ± 5％; 12VDC± 5％
1.5Amp (5V) ；2 Amp (12V)
http://www.wjel.net
Page 10 of 55
4.4 PANEL SPECIFICATION
4.4.1 Display Characteristics
AOC LM923
4.4.2 Optical Characteristics
http://www.wjel.net
Page 11 of 55
4.4.3 Parameter guide line for CCFL Inverter
AOC LM923
http://www.wjel.net
Page 12 of 55
5. BLOCK DIAGRAM
5.1 MONITOR EXPLODED VIEW
bezel 34G1275AKG-3B
AOC LM923
Key pad 33G4713 AS L
stand 34G1273-GM-B
main frame 15G6093 AU
rear cover 34G1276-GM -4B
shield 85G6081-5
hinge ass’y 37G 490 1
clamp 33G4695 -1-C
base 34G1277-GM-B
http://www.wjel.net
Page 13 of 55
5.2 SOFTWARE FLOW CHART
AOC LM923
1
2
N
4
5
Y
6
7
Y
N
N
3
9
10
Y
N
http://www.wjel.net
18
N
12
Y
14
19
N
11
13
15
17
N
Y
N
Y
16
Y
Page 14 of 55
1) MCU initialize.
2) Is the EPROM blank?
3) Program the EPROM by default values.
4) Get the PWM value of brightness from EPROM.
5) Is the power key pressed?
6) Clear all global flags.
7) Are the AUTO and SELECT keys pressed?
8) Enter factory mode.
9) Save the power key status into EPROM.
Turn on the LED and set it to green color.
Scalar initializes.
10) In standby mode?
11) Update the lifetime of back light.
12) Check the analog port, are there any signals coming?
AOC LM923
13) Does the scalar send out an interrupt request?
14) Wake up the scalar.
15) Are there any signals coming from analog port?
16) Display "No connection Check Signal Cable" message. And go into standby mode after the message
disappear.
17) Program the scalar to be able to show the coming mode.
18) Process the OSD display.
19) Read the keyboard. Is the power key pressed?
http://www.wjel.net
Page 15 of 55
5.3 ELECTRICAL BLOCK DIAGRAM
_
5.3.1 Main Board
AOC LM923
EPR_SDA
EPR_SCL
EEPROM
AT24C16N
(U602)
W78E65
MCU
(U601)
Key Board
Control
Crystal
14.318MHZ
(X401)
LCD Interface
(CN503)
Scalar IC MST8111B
(Include ADC, OSD)
(U401)
D-Sub
Connector
(CN301)
H sync
V sync
RGB
DB15_SDA,
DB15
EEPROM
24C02
(U301)
SCL
http://www.wjel.net
Page 16 of 55
5.3.2 Inverter/Power Board
AC input
EMI filter
Bridge Rectifier and Filter
AOC LM923
Rectifier
Transformer
diode
Start Circuit: R906、 R907
CN902
12V
PWM Control IC
Over Voltage Protect
Feedback
Circuit
Lamp
OSC and
Output
Circuit
Feedback Circuit
Over Voltage
DC Convert Circuit
MOSFET
PWM Control IC
ON/OFF Control
DIM
DIM
http://www.wjel.net
Page 17 of 55
Loading...
+ 38 hidden pages
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use