AOC 831S+ User manual

18.5" LCD Color Monitor AOC 831S+
1
Service
Service
Service
HorizontalFrequency
30-80kHz
TABLE OF CONTENTS
Description Page Description Page
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.
Table Of Contents…………………………………………...1
Revision List………………………………………………....2
Important Safety Notice.…….........................……...... 3
1. Monitor Specification..............................…………........4
2. LCD Monitor Description…………………………….......5
3. Operation Instructions....................................…...........6
3.1. General Instructions...........................…....................6
3.2. Control Button…………………………….…...............6
3.3 Adjusting the Picture...........................…..............7
4. Input/Output Specification............……………............11
4.1. Input Signal Connector............………….................11
4.2. Factory Preset Display Modes......…..................12
4.3. Panel Specification.....………………..................13
5. Block Diagram….........................................................15
5.1 Software Flow Chart………………………….……….15
5.2.Electrical Block Diagram…………………….......17
6. Schematic……………..............................................19
6.1 Main Board....……….............................................19
6.2 Power Board………………………………………....24
6.3 Key Board…………………...….……………………26
7. PCB Layout..………….............................................27
7.1. Main Board………................................................27
7.2. Power Board….....................................................28
7.3. Key Board….........................................................29
8. Maintainability………...............................................30
8.1.Equipments and Tools Requirement......................30
8.2.Trouble Shooting………........................................32
9. White-Balance, Luminance adjustment………..…...38
10. Monitor Exploded View…………………….…........40
11. BOM List…............................................................41
12. Different Parts List…………………………….…….62
CAUTION: USE A SEPARATE ISOLATION TRANSFOMER FOR THIS UNIT WHEN SERVICING

18.5" LCD Color Monitor AOC 831S+
2
Revision List
Version Date Revision History TPV Model Name
A00 Sep.-8-2008 Initial release T8RCM5NQW5A2NN
T8RCM5NKW5A2NN
T8RCM5NCW5A2NN
A01 Oct.-21-2008 Add new BOM
T8RCM5NLW5CKNZ
T8RCM5NBW5A1NN
A02 Nov.-21-2008 Add new BOM
T8RCM5NLW5CKNZ
A03 Dec.-25-2008 Add new BOM T8RCM5NCW5A2NNJ

18.5" LCD Color Monitor AOC 831S+
3
Important Safety Notice
Proper service and repair is important to the safe, reliable operation of all AOC Company Equipment. The service
procedures recommended by AOC and described in this service manual are effective methods of performing service
operations. Some of these service operations require the use of tools specially designed for the purpose. The
special tools should be used when and as recommended.
It is important to note that this manual contains various CAUTIONS and NOTICES which should be carefully read in
order to minimize the risk of personal injury to service personnel. The possibility exists that improper service
methods may damage the equipment. It is also important to understand that these CAUTIONS and NOTICES ARE
NOT EXHAUSTIVE. AOC could not possibly know, evaluate and advise the service trade of all conceivable ways in
which service might be done or of the possible hazardous consequences of each way. Consequently, AOC has not
undertaken any such broad evaluation. Accordingly, a servicer who uses a service procedure or tool which is not
recommended by AOC must first satisfy himself thoroughly that neither his safety nor the safe operation of the
equipment will be jeopardized by the service method selected.
Hereafter throughout this manual, AOC Company will be referred to as AOC.
WARNING
Use of substitute replacement parts, which do not have the same, specified safety characteristics may create shock,
fire, or other hazards.
Under no circumstances should the original design be modified or altered without written permission from AOC.
AOC assumes no liability, express or implied, arising out of any unauthorized modification of design.
Servicer assumes all liability.
FOR PRODUCTS CONTAINING LASER:
DANGER-Invisible laser radiation when open AVOID DIRECT EXPOSURE TO BEAM.
CAUTION-Use of controls or adjustments or performance of procedures other than those specified herein may
result in hazardous radiation exposure.
CAUTION -The use of optical instruments with this product will increase eye hazard.
TO ENSURE THE CONTINUED RELIABILITY OF THIS PRODUCT, USE ONLY ORIGINAL MANUFACTURER'S
REPLACEMENT PARTS, WHICH ARE LISTED WITH THEIR PART NUMBERS IN THE PARTS LIST SECTION OF
THIS SERVICE MANUAL.
Take care during handling the LCD module with backlight unit
-Must mount the module using mounting holes arranged in four corners.
-Do not press on the panel, edge of the frame strongly or electric shock as this will result in damage to the screen.
-Do not scratch or press on the panel with any sharp objects, such as pencil or pen as this may result in damage to
the panel.
-Protect the module from the ESD as it may damage the electronic circuit (C-MOS).
-Make certain that treatment person’s body is grounded through wristband.
-Do not leave the module in high temperature and in areas of high humidity for a long time.
-Avoid contact with water as it may a short circuit within the module.
-If the surface of panel becomes dirty, please wipe it off with a soft material. (Cleaning with a dirty or rough cloth may
damage the panel.)

18.5" LCD Color Monitor AOC 831S+
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1. Monitor Specification
Model number 831S+
Driving system TFT Color LCD
Viewable Image Size 470mm diagonal
Pixel pitch 0.3mm(H) x 0.3mm(V)
Video R, G, B Analog interface
Separate Sync. H/V TTL
Display Color 16.7M Colors
LCD Panel
Dot Clock 85.5 MHz
Horizontal scan range 30 kHz - 80 kHz
Horizontal scan Size(Maximum) 409.8mm
Vertical scan range 55 Hz - 75 Hz
Vertical scan Size(Maximum) 230.4mm
Optimal preset resolution 1366 x 768 (60 Hz)
Highest preset resolution 1366 x 768 (60 Hz)
Plug & Play VESA DDC2B/CI
Input Connector D-Sub 15pin
Input Video Signal Analog: 0.7Vp-p(standard), 75 OHM, Positive
Power Source 100~240VAC, 50/60Hz
Active < 25W
Resolution
Power Consumption Standby < 1 W
Connector Type 15-pin Mini D-Sub
Signal Cable Type Detachable
Dimensions & Weight:
Height (with base) 357.9mm
Width 455.2mm
Depth 219.7mm
Weight (monitor only) 3.89 kg
Physical
Characteristics
Weight (with packaging) 5.26kg
Temperature:
Operating 0° to 50°
Non-Operating -20°to 60°
Humidity:
Operating 10% to 85% (non-condensing)
Non-Operating 5% to 80% (non-condensing)
Altitude:
Operating 0~ 3000m (0~ 10000 ft )
Environmental
Non-Operating 0~ 5000m (0~ 15000 ft )

18.5" LCD Color Monitor AOC 831S+
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2. LCD Monitor Description
The LCD Monitor will contain main board, power board, key 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.
AC-IN
100V~240V
Video signal, DDC
Power Board
(
Include ada
p
ter and inverter
)
Flat Panel and
CCFL backlight
Main Board RS232 Connector
For white balance
adjustment in
factory mode
HOST Computer
CCFT Drive.
Monitor Block Diagram
Key board

18.5" LCD Color Monitor AOC 831S+
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3. Operation Instructions
3.1 General Instructions
Press the power button to turn the monitor on or off. The 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.
-Press the power button to turn on the monitor, the power indicator will light up.
3.2 Control Buttons
1 Eco mode (DCR) / -
2 4:3 or wide / +
3 Power
4 Auto / Exit
5 Menu / Enter

18.5" LCD Color Monitor AOC 831S+
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3.3 Adjusting the Picture
OSD Settings
1.Press the MENU-button to activate the OSD window.
2.Press+ or - to navigate through the functions. Once the desired function is highlighted, press the MENU-buttonto
activate it.If the function selected has a sub-menu, press or again to navigate through the sub-menu functions.Once
the desired function is highlighted, press MENU-button to activate it.
3.Press+ or - to change the settings of the selected function. To exit and save, select the exit function. If you want to
adjust any other function, repeat steps 2-3.
4.OSD Lock Function: To lock the OSD, press and hold the Menu button while the monitor is off and then press
power button to turn the monitor on. To un-lock the OSD - press and hold the Menu button while the monitor is off
and then press power button to turn the monitor on.
5.Eco Mode and DCR hot key : Press the Eco key continuously to select the Eco mode of brightness and DCR on
when there is no OSD ( Eco mode hot key may not be available in all models).
6.4:3 or wide image ratio hot key: When there is no OSD, press + continuously to change 4:3 or wide image ratio. (If
the product screen size is 4:3 or input signal resolution is wide format, the hot key is disalbe to adjust.)
7.Auto configure hot key: When the OSD is closed, press Auto button will be auto configure hot key function .

18.5" LCD Color Monitor AOC 831S+
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OSD functions
Luminance Adjust Range Description
Brightness 0-100 Backlight Adjustment
Contrast 0-100 Contrast from Digital-register.
Standard
Standard Mode
Text
Text Mode
Internet
Internet Mode
Game
Game Mode
Movie
Movie Mode
Eco mode
Sports
Sports Mode
Gamma1 Adjust to Gamma1
Gamma2 Adjust to Gamma 2
Gamma
Gamma3 Adjust to Gamma 3
Off
Disable dynamic contrast ratio
DCR
On
Enable dynamic contrast ratio
Image Setup
Clock 0-100 Adjust picture Clock to reduce
Vertical-Line noise.
Phase 0-100 Adjust Picture Phase to reduce
Horizontal-Line noise
H. Position 0-100 Adjust the horizontal position of
the picture.
V. Position 0-100 Adjust the vertical position of the
picture.
Color Temp.
Warm 6500K
Recall Warm Color Temperature
from EEPROM.
Normal 7300K
Recall Normal Color Temperature
from EEPROM.

18.5" LCD Color Monitor AOC 831S+
9
Cool 9300K
Recall Cool Color Temperature
from EEPROM.
sRGB Recall SRGB Color Temperature
from EEPROM.
User-R Red Gain from Digital-register
User-G Green Gain Digital-register.
User
User-B Blue Gain from Digital-register
Color Boost
Full Enhance on or off Disable or Enable Full Enhance
Mode
Nature Skin on or off Disable or Enable Nature Skin
Mode
Green Field on or off Disable or Enable Green Field
Mode
Sky-blue on or off Disable or Enable Sky-blue Mode
AutoDetect on or off Disable or Enable AutoDetect
Mode
Demo on or off Disable or Enable Demo
Picture Boost
Frame Size 14-100 Adjust Frame Size
Brightness 0-100 Adjust Frame Brightness
Contrast 0-100 Adjust Frame Contrast
H. position 0-100 Adjust Frame horizontal Position
Position
V. position 0-100 Adjust Frame vertical Position
Bright Frame on or off Disable or Enable Bright Frame
OSD Setup
H. Position 0-100 Adjust the horizontal position of
OSD
V. Position 0-100 Adjust the vertical position of OSD
Timeout 5-120 Adjust the OSD Timeout
Transparence 0-100 Adjust the transparence of OSD
Language Select the OSD language
Extra
Auto Select to Auto Detect input signal
Analog Select Analog Sigal Source as
Input
Input Select
Digital Select Digital Sigal Source as
Input

18.5" LCD Color Monitor AOC 831S+
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Auto Config yes or no Auto adjust the picture to default
Image Ratio wide or 4:3 Select wide or 4:3 format for
display
DDC-CI yes or no Turn ON/OFF DDC-CI Support
Information Show the information of the main
image and sub-image source
Reset
Reset yes or no Reset the menu to default
Exit
Exit Exit the main OSD

18.5" LCD Color Monitor AOC 831S+
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4. Input/Output Specification
4.1 Input Signal Connector
D-Sub 15pin Connector
Pin Number 15-Pin Side of the Signal Cable
1 Video-Red
2 Video-Green
3 Video-Blue
4 N.C.
5 Detect Cable
6 GND-R
7 GND-G
8 GND-B
9 +5V
10 Ground
11 N.C.
12 DDC-Serial data
13 H-sync
14 V-sync
15 DDC-Serial clock

18.5" LCD Color Monitor AOC 831S+
12
4.2 Factory Preset Display Modes
Stand Resolution
Horizontal
Frequency(KHz)
Vertical
Frequency(Hz)
VGA 640×480 @60Hz 31.469 59.940
VGA 640×480 @67Hz 35.000 66.667
VGA 640×480 @72Hz 37.861 72.809
VGA 640×480 @75Hz 37.500 75.000
Dos-mode 720×400 @70Hz 31.469 70.087
SVGA 800×600 @56Hz 35.156 56.250
SVGA 800×600 @60Hz 37.879 60.317
SVGA 800×600 @72Hz 48.077 72.188
SVGA 832×624 @75Hz 46.875 75.000
Mac-mode 832×624 @75Hz 49.725 74.500
XGA 1024×768 @60Hz 48.363 60.004
XGA 1024×768 @70Hz 56.476 70.069
XGA 1024×768 @72Hz 57.500 72.074
XGA 1024×768 @75Hz 60.023 75.029
wXGA 1366×768 @60Hz 59.856 47.765

18.5" LCD Color Monitor AOC 831S+
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4.3. Panel Specification
4.3.1 General Feature
CLAA185WA02 is 18.51” color TFT-LCD (Thin Film Transistor Liquid Crystal Display) module composed of LCD
panel, driver ICs, control circuit and backlight. By applying 6bit+Hi-FRC digital data,1366*768, 16.7M-color images
are displayed on the 18.51” diagonal screen. Input power voltage is 5.0V for LCD driving. Inverter for backlight is not
included in this module. General specification are summarized in the following table:
4.3.2 Optical Characteristics
Ta=25℃，VCC=5.0V

18.5" LCD Color Monitor AOC 831S+
14
4.3.3 Electrical Characteristics
(1).TFT-LCD
(2).Backlight

18.5" LCD Color Monitor AOC 831S+
15
5. Block Diagram
5.1 Software Flow Chart
1
2
N
Y
5
Y
N
10
Y
N
12
Y
N
7
Y
N
6
4
3
8
9
14
11
13
Y
N
15
Y
N
16
17
19
Y
N
18

18.5" LCD Color Monitor AOC 831S+
16
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 initializes.
10) In standby mode?
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
disappears.
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?

18.5" LCD Color Monitor AOC 831S+
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5.2 Electrical Block Diagram
Main Board
Crystal 14.318MHZ
(X401)
EEPROM
SST25LF020A
(U402)
Scalar TSUM1PFR-LF
(Include ADC, OSD, MCU)
(U401)
D-Sub Connector
(CN101)
H sync
V sync
RGB
Panel Interface
(CN601)

18.5" LCD Color Monitor AOC 831S+
18
Power Board
VEMI filter Rectifier Transformer Outputer
Rectifier
5V
5.1V
12V
Audio
circuit
Power Switching
Sense Resistor
PWM Control IC
IC Power Supply
Photo Couple Sampling
12V DC Switching MOS Transformer Resonance NET High Voltage Output
IC Power Supply
Converter PWM Control IC Open Lamp Protection
Current Sampling
AC input
100V~24

18.5" LCD Color Monitor AOC831S+
19
6. Schematic
6.1 Main Board
715G2904 1 2
DSUB_5V
DSUB_5V
PA[0..1]
CMVCC
CMVCC1
XGA/SXGA
TSUM16FWR SCHEMATIC
LVDS OUTPUT
CMVCC1
VCC3.3
OEM MODEL Size
Rev
Date
Sheet of
TPV MODEL
PCB NAME
称爹
T P V ( Top Victory Electronics Co . , Ltd. )
Key Component
絬 隔 瓜 絪 腹 1C-2
A
37Wednesday , May 21, 2008
715G2904-1C-2 <
称爹 >
01.Top
ESD_VCC
ESD_VCC
04.Output
CMVCC
PB[0..9]
PA[0..1]
PPWR_ON#
PA[4..9]
02.Input
DSUB_R+
DSUB_G+
DSUB_B+
DSUB_V
DSUB_R-
DSUB_G-
DSUB_B-
DET_CABLE
DSUB_H
DSUB_SOG
DDC1_SDA
DDC1_SCL
DSUB_5V
VCC3.3
ESD_VCC
03.Scalar
DSUB_R+
DSUB_G+
DSUB_SOG
DSUB_B+
DSUB_R-
DSUB_G-
DSUB_B-
DSUB_H
DSUB_V
Adj_BACKLIGHT
VCC1.8
VCC3.3
PA[0..1]
PB[0..9]
DDC1_SDA
DDC1_SCL
DET_CABLE
on_BACKLIGHT
PPWR_ON#
PANEL_ID#
Volume#
Mut e
CMVCC
PA[4..9]
CMVCC1
VCTRL
05.Power
on_BACKLIGHT
Adj_BACKLIGHT
VCC1.8
CMVCC
VCC3.3
Mut e
Volume#
PANEL_ID#DSUB_5V
CMVCC1
VCTRL
ESD_VCC
VCC1.8
VCC3.3
CMVCC
VCC1.8
CMVCC
VCC3.3
PB[0..9]
PA[4..9]

18.5" LCD Color Monitor AOC831S+
20
VGA_PLUG
VCC3.3 7
DSUB_5V 5
DDC1_SCL5
DSUB_SCL
DSUB_SDA
ESD_VCC
ESD_VCC
ESD_VCC 5
C114
NC
I/O1
1
GND
2
I/O2
3I/O3 4
VDD 5
I/O4 6
U102
AZC099-04S
VGA_R+ VGA_B+
VGA_G+
V_Sy nc
R120
10K 1/16W 5%
1 2
FB103
BEAD
1 2
ZD103
UDZSNP5.6B
R113
100R 1/16W 5%
C107
0.047uF
C103
22pF
1
6
2
7
3
8
4
9
5
11
12
13
14
15
10
17 16
CN101
DB15
R111
100R 1/16W 5%
R104
100R 1/16W 5%
C111
5pF/50V
1 2
FB102
BEAD
R118
1K 1/16W 5%
C105
0.047uF
R110
100R 1/16W 5%
1 2
FB101
BEAD
R101 0R05 1/10W 5% R102 100R 1/16W 5%
R117
100R 1/16W 5%
C113
0.047uF
R121
10K 1/16W 5%
C110
0.047uF
C102
22pF
R106
2K2 1/16W 5%
R112
75R 1/16W 5%
R107
75R 1/16W 5%
C109
0.047uF
R105
2K2 1/16W 5%
C108
5pF/50V
C104
5pF/50V
R115
100R 1/16W 5%
R108
100R 1/16W 5%
1 2
ZD104
UDZSNP5.6B
R103 100R 1/16W 5%
R109
390 OHM 1/16W
C101
0.047uF
R116
75R 1/16W 5%
C106
0.047uF
R114
100R 1/16W 5%
GND POWER
DSUB_5V
DGND
VCC3.3
H_Sy nc
DDC1_SDA5
OEM MODEL
Size
Rev
Date
Sheet of
TPV MODEL
PCB NAME
称爹
T P V ( Top Victory Electronics Co . , Ltd. )
Key Component
絬 隔 瓜 絪 腹 1C-2
B
47Wednesday , May 21, 2008
715G2904-1C-2 <
称爹 >
02.Input
DSUB_H 5
DSUB_V 5
DET_CABLE 5
DSUB_R- 5
DSUB_R+ 5
DSUB_G- 5
DSUB_G+ 5
DSUB_SOG 5
DSUB_B- 5
DSUB_B+ 5
DSUB_5V
V_Sy nc
VGA_R-
VGA_R+
VGA_G-
VGA_B+
DSUB_SCL VGA_PLUG
VGA_G-
VGA_G+
DDC1_SDA DSUB_SDA
VGA_R-
VCC3.3
VGA_B-
VGA_B-
VGA_G+
VGA_B+
DDC1_SCL
H_Sync
VGA_R+
I/O1
1
GND
2
I/O2
3I/O3 4
VDD 5
I/O4 6
U103
AZC099-04S C115
NC