AOC LM540 Service Manual
AOC LM540
SERVICE MANUAL
15” LCD Monitor
LM540
http://www.wjel.net
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 RE LIABILITY
FOR CHANGES, ERRORS OR OMISSIONS.
MANUFACTURE DATE: Sep-15-2005
Page 1 of 51
AOC LM540
REVISION DATE MODIFIACTION
A00 Sep-15-2005 Initial release
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AOC LM540
TABLE OF CONTENTS
Revision List ---------------------------------------------------------------------------------- 02
Table of Contents ---------------------------------------------------------------------------------------- 03
1. Monitor Specifications --------------------------------------------------------------------------------04
2.LCD Monitor Description -----------------------------------------------------------------------05
3.Operation Instructions --------------------------------------------------------------------------06
3.1 General Instructions -----------------------------------------------------------------------06
3.2 Control Button ------------------------------------------------------------------------------06
3.3 Adjusting The Picture ---------------------------------------------------------------------07～ 08
4. Input/Output Specification ------------------------------------------------------------------- 09
4.1 Input Signal Connector -------------------------------------------------------------------09
4.2 Factory Preset Display Modes ----------------------------------------------------------10
4.3 Power Supply Requirements ------------------------------------------------------------10
5.Panel Specification----------------------------------------------------------------------------------11
5.1 General Feature ----------------------------------------------------------------------------11
5.2 Optical Characteristics --------------------------------------------------------------------12
6. Block Diagram -----------------------------------------------------------------------------------13
6.1 Software Flow Chart -----------------------------------------------------------------------13～ 14
6.2 Electrical Block Diagram -----------------------------------------------------------------15～ 16
7. Schematic -----------------------------------------------------------------------------------------17
7.1 Main Board ---------------------------------------------------------------------------------17～ 21
7.2 Power Board -------------------------------------------------------------------------22～ 23
8. PCB Layout ---------------------------------------------------------------------------------------24
8.1 Main Board ----------------------------------------------------------------------------------24
8.2 Power Board --------------------------------------------------------------------------------25
8.3 KEY Board ------------------------------------------------------------------------------ 25
9. Maintainability -----------------------------------------------------------------------------------26
9.1 Equipments and Tools Requirements -------------------------------------------------26
9.2 Trouble Shooting ---------------------------------------------------------------------------27～ 32
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10. White-Balance, Luminance Adjustment ----------------------------------------------- 33
11. Check List after replacing LCD Main board----------------------------------------------- 34～36
12. EDID Content ---------------------------------------------------------------37
13. BOM List ----------------------------------------------------------------------------------38～51
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1. MONITOR SPECIFICATIONS
Driving system TFT LCD
Size 38cm(15.0")
AOC LM540
LCD Panel
Input signals
Type
Pixel pitch 0.297mm(H) x 0.297mm(V)
Viewing angle 130(H) 100(V) (R>10)
Luminance 250cd/ m2
Contrast Ratio 400:1
Response time 35ms (typ)
Display colors 6-bits driver
R G B Analog 0.7Vp-p
H/V separate TTL level
H/V composite TTL level
Horizontal frequency 30kHz–60kHz
Vertical rate 55-75Hz
Recommend resolution 1024 x768 @60HZ
HSD150SX84-C（HSD）
Power consumption
Power supply AC voltage
Operating condition Temperature 5-50°C
Storage Condition Temperature -20-60°C
Dimension Unpackaged 356 mm (W) x360mm (H) x 150mm (D)
Maximum Screen Size
ON MODEL
OFF MODEL
Horizontal: 304.1mm，Vertical: 228.1mm
≤30W
≤1W
100~240VAC,50~60Hz
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AOC LM540
(
)
2. LCD MONITOR DESCRIPTION
The LCD MONITOR will contain a main board, a power board and a keypad 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
CCFT Drive
.
Main Board
Keyboard
Flat Panel and
CCFL backlight
HOST Computer
RS232 Connector
For white balance
adjustment in
factory mode
Video signal, DDC
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AOC LM540
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 position. The power indicator will light up.
3.2 FRONT PANEL CONTROL
NO. Name Within OSD Without OSD
1 Auto/Exit
1. Exit Sub menu
2. Exit the menu item
1.Move the cursor to left
2 Brightness
2.Adjust down when menu item selected
1.Move the cursor to right
3 Contrast
2.Adjust up when menu item selected
Run the Auto Adjust when this
button keep to push for 2 second
Open the Brightness menu
Open the contrast menu
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4 MENU Select Function or select Sub menu Activate OSD main menu
5 Indicator Green—On Red—Save Green—On Red—Save
6 Power Power On / Off Power On / Off
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3.3 ADJUSTING THE PICTURE
A
THE DESCRIPTION FOR CONTROL FUNCTION:
AOC LM540
Main Menu
Item
Luminance
Image Setup
Image
Position
Main
Menu
Icon
Sub Menu
Item
Contrast
Brightness
Focus
Clock
H. Position
V. Position
C1 N/A
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C2 N/A
Sub Menu
Icon
Description
Contrast from Digital-register. 0-100
Backlight Adjustment 0-100
Adjust Picture Phase to reduce
Horizontal-Line noise
Adjust picture Clock to reduce
Vertical-Line noise.
Adjust the horizontal position of the
picture.
Adjust the vertical position of the
picture.
Recall warm Color Temperature
from EEPROM.
Recall cool Color Temperature from
EEPROM.
Adjust
Range
0-100 Do Auto Config
0-100 Do Auto Config
0-100 Do Auto Config
0-100 Do Auto Config
N/A
N/A
Reset Value
Recall Cool
Contrast Value
Recall Cool
Brightness Value
The Color
Temperature will
be set to Cool.
Color Temp.
Auto Config
(Analog-Only
User / Red
User /
Green
User / Blue
Green Gain from Digital-register. 0-100
uto Adjust the H/V Position, Focus
Yes N /A
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Red Gain from Digital-register. 0-100
Blue Gain from Digital-register. 0-100
N/A N/A
and Clock of picture.
The User R/G/B
value (default is
100) will not be
Modified by Reset
function.
AOC LM540
Model)
OSD Setup
Language
No N/A
H. Position
V. Position
OSD
Timeout
English N/A
Deutsch N/A
Français N/A
Español N/A Set OSD display language to Spain. N/A
Italiano N/A Set OSD display language to Italian. N/A
Do not execute Auto Config, return
to main menu.
Adjust the horizontal position of the
Adjust the vertical position of the
Adjust the OSD timeout. 10-120 10
Set OSD display language to
Set OSD display language to
Set OSD display language to
OSD.
OSD.
English.
German.
French.
N/A N/A
0-100 50
0-100 50
N/A
N/A
N/A
The Language
will be set to
English.
Information
Reset
Exit
Show the resolution, H/V frequency
Information N/A
Yes N /A
No N/A
N/A N/A Exit OSD N/A N/A
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.
N/A N/A
N/A N/A
N/A N/A
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4. INPUT/OUTPUT SPECIFICATION
4.1 INPUT SIGNAL CONNECTOR
ANALOG D-SUB CONNECTOR
PIN NO. DESCRIPTION PI N NO. DESCRIPTION
AOC LM540
1.
2.
3.
4.
5.
6.
7.
8.
Red
Green
Blue
TXD
Ground
R-Ground
G-Ground
B-Ground
VGA connector layout
9.
10.
11.
12.
13.
14.
15.
15
6
11 15
10
+5V
VGA-CON
RXD
DDC-Serial Data
H-Sync
V-Sync
DDC-Serial Clock
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4.2 FACTORY PRESET DISPLAY MODES
AOC LM540
STANDARD
Dos-mode 720 x 400
VGA
SVGA
XGA
FREQUENCY HORIZONTAL VERTICAL
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
4.3 POWER SUPPLY REQUIREMENT
A/C Line voltage range : 100 V ~ 240 V
A/C Line frequency range
Current : 0.6A max. at 100V , 0.35A max. at 240 V <0.3A
Peak surge current : < 55A peak at 240 VAC and cold starting
31.47kHz 70.0Hz
: 50 ± 3Hz, 60 ± 3Hz
Leakage current : < 3.5mA
Power line surge
Voltage
CURRENT : 3.5 Amp (max)
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: No advance effects (no loss of information or defect)
with a maximum of 1 half-wave missing per second
: 12VDC ± 5％
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5. PANEL SPECIFICATION
5.1 GENERAL FEATURE
z 15” XGA TFT LCD panel
z 2 CCFLs Backlight system
z Supported XGA (V: 768 lines, H: 1024 pixels) resolution
z Supported to 75Hz refresh rate
z Without LCD Timing Controller
Display Characteristics
AOC LM540
Power consumption
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11.0 (type.)
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5.2 OPTICAL SPECIFICATION
(5)
AOC LM540
400
35
(1)
ELECTRICAL SPECIFICATIONS
0.593
0.305
0.263
0.569 0.599
0.083 0.113
0.623
0.335
0.293
75
0.365
0.323
0.629
0.143
(6)
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7.0
100
6. BLOCK DIAGRAM
6.1 SOFTWARE FLOWING CHART
AOC LM540
1
2
4
Y
3
N
N
5
6
9
10
12
N
Y
6
N
7
Y
N
Y
8
11
13
N
Y
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18
N
14
19
Y
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15
17
Y
N
16
Y
REMARK:
1) MCU initialize.
2) Is the EEprom blank?
3) Program the EEprom by default values.
4) Get the PWM value of brightness from EEprom.
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 EEprom.
Turn on the LED and set it to green color.
Scalar initialize.
10) In standby mode?
AOC LM540
11) Update the lifetime of back light.
12) Check the analog port, are they’re any signals coming?
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?
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6.2 ELECTRIAL BLOCK DIAGRAM
6.2.1 MAIN BOARD
AOC LM540
Flash Memory
W49F002
(U202)
EPR_SDA
EPR_SCL
EEPROM
24C16
(U204)
LCD Interface
(CN501, CN502)
Scalar gm2115
(Include MCU, ADC, OSD)
(U203)
D-Sub
Connector
(CN1)
H sync
V sync
RGB
OSD Control
Interface
(CN503)
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DB15_SDA,
DB15_SCL
EEPROM
M24C02
(U104)
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6.2.2 INVERTER/POWER BOARD
AC input
EMI filter
Bridge
Rectifier
and Filter
Transformer
AOC LM540
Rectifier
CMOS
Lamp
Start Circuit
R906, R907
OSC and
Output
Circuit
Feedback
Circuit
PWM
Control IC
Over
Voltage
DC Convert
Circuit
MOSFET
Q203/Q204
PWM
Control IC
Over
Voltage
Protect
CON102
5V
12V
ON/OFF
ON/OFF
Control
DIM
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