BenQ Q74A User manual

Q74A
Service Manual

Q74A Service Manual
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Contents
PRECAUTIONS................................................................................................. 4
ITEMS ............................................................................................................ 6
HOW TO CONNECT THE SEVERAL CABLES TO THE LCD MONITOR.......................... 7
▶Setting up the LCD monitor..................................................................... 7
ADJUSTING THE MONITOR................................................................................ 8
Q74A SPECIRICATIONS...................................................................................... 9
▶Q74A Specifications .................................................................................. 9
DISPLAY MODES............................................................................................ 10
PowerSaver..................................................................................................... 10
OSD MENU.................................................................................................... 11
▶Menu Tree............................................................................................ 11
FACTORY SET ................................................................................................ 12
BURN-IN MODE ............................................................................................. 12
INVERTER & POWER ...................................................................................... 13
▶Inverter & POWER(Q74A)........................................................................ 13
▶Specification ......................................................................................... 13
▶Electrical Characteristics........................................................................... 13
▶Pin Connection ...................................................................................... 14
TROUBLESHOOTING ...................................................................................... 15
▶No operating at all................................................................................... 15
▶Doesn’t display on LCD............................................................................ 16
EXPLODE VIEW ............................................................................................. 18
▶Q74A.................................................................................................. 18
PART LIST ..................................................................................................... 19
▶Q74A Mechanical Part List ........................................................................ 19
▶Q74AAD B/D Part List ............................................................................ 20
▶Q74A FUNCTION KEY B/D Part List........................................................... 23
▶Q74A FUNCTION LED B/D Part List........................................................... 23
▶Inverter & POWER BD Part List(FLF1742-20A) .............................................. 24
▶Inverter & POWER BD Part List(FLF1742-20A) .............................................. 25
CIRCUIT DIAGRAM ........................................................................................ 26
▶AD B/D(Q74A)...................................................................................... 26
▶Inverter & POWER B/D(FLF1742-20A) ........................................................ 31
PCB Layout .................................................................................................... 34
▶AD B/D TOP SILK (Q74A) ....................................................................... 34

Q74A Service Manual
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▶AD B/D TOP PATTERN (Q74A) ................................................................. 35
▶AD B/D BOTTOM SILK (Q74A) ................................................................36
▶AD B/D MASK TOP (Q74A) ..................................................................... 37
▶AD B/D MASK BOTTOM (Q74A) .............................................................. 38
▶FUNC B/D TOP SILK (Q74A).................................................................... 39
▶FUNC KEY B/D BOTTOM PATTERN (Q74A)................................................ 39
▶FUNC LED B/D TOP SILK (Q74A) ............................................................. 39
▶FUNC LED B/D BOTTOM PATTERN (Q74A)................................................ 39

Q74A Service Manual
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Q74A
PRECAUTIONS
Warning : The following information will help you avoid the risk of electric shock,
serious injury, and death.
zPlug the power cord into a properly grounded outlet.
There is the risk of electric shock.
zIf you hear a noise or smell smoke from the computer or adaptor, unplug the power cord
immediately, and call the service center.
There is the risk of electric shock or fire.
zDo not overload an electrical outlet with too many devices.
There is the risk of fire.
zDo not unplug from the outlet by pulling the power cord or when your hands are wet.
There is the risk of electric shock or fire.
zDo not bend the power cord excessively or place heavy objects on it. Keep children and pets
away from the power cord as they may damage the power cord. There is the risk of electric
shock or fire.
zDo not use a damaged power cord or plug. Make sure the plug fits snugly into the outlet.
There is the risk of electric shock or fire.
zDo not expose the monitor to the direct sun light.
zDo not block the fan louvers.
There is the risk of fire or damage to the monitor.
zDo not attempt to disassemble, fix, or modify the monitor.
There is the risk of electric shock or fire.
zKeep the monitor away from high temperature, humidity, and dust.
Operating environment = 0 ~ 40 Degrees Celsius
Operating environment = 30 ~ 80 Relative Humidity
zDo not allow any object or liquid to enter inside the monitor.
There is the risk of electric shock, fire, or damage to the monitor.

Q74A Service Manual
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Caution : The following information will help you avoid the risk of minor ofr moderate
injury,or damage to the monitor.
zUse a proper voltage/current level indicated.
zDo not clean the LCD with abrasive chemicals.
There is the risk of damage to the LCD.
zDo not scratch and damage the LCD with sharp objects.
zKeep the monitor away from objects and electrical appliances that may generate
electromagnetic fields.
zPlace the monitor on a flat, stable surface.
The monitor may fall and there is the risk of damage or injury.
zUnplug the power cord when the monitor is not in use for a prolonged period of time.
Instruction for Cleaning the Monitor
zMake sure the power cord is unplugged.
zDo not spill or pour liquid on the monitor.
zCleaning the LCD panel
1. Use a clean, soft cloth to wipe off dust from the LCD.
2. If still not clean, wipe the LCD with a clean soft cloth with a small amount of glass cleaner
without alcohol or ammonia.
zCaution
Do not use alcohol or ammonia based cleaning products. Abrasive chemicals, such as alcohol or
ammonia, may damage the monitor. The company is not responsible for the damages to the monitor
caused by the use of alcohol or ammonia based cleaning products.

Q74A Service Manual
ITEMS
◈ LCD Monitor
◈ Stand
◈ Power Cord
◈ 15pin D-Sub Cable
◈ User Manual
◈ 24pin DVI Cable *1
◈ Audio Cable *2
*1 : For DVI Model Only. *2 : For Audio Model Only.
Notice
Please make sure the following items are included with your monitor.
If any items are missing, contact your dealer. .
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Q74A Service Manual
HOW TO CONNECT THE SEVERAL CABLES TO THE LCD
MONITOR
▶Setting up the LCD monitor
No. Name Cable connections
1 Power Power Cord
2 PC 15-pin D-Sub Signal Cable
3 DVI DVI-D Cable *1
4 SPK IN Audio Cable *2
5 SPK OUT External Speaker Cable *2
*1 : For DVI Model Only
*2 : For Audio Model Only
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Q74A Service Manual
ADJUSTING THE MONITOR
The Function Control Buttons
How to use the Function Key
Menu Key:
1. First click : The OSD main menu appears.
2. Second click : The OSD main menu disappears.
Select Key : Select a command function.
Down Key :
1. Move the on-screen highlighted comand
item to the next one.
2. Decrease the current option value.
Mute Key : *2
Sound MUTE ON/OFF Button.
Up Key :
1. Move the on-screen highlighted comand
item to the previous one.
2. Increase the current option value.
Auto Key : *1
This will optimize image quality automatically.
MWE Key : You can manually adjust the screen to your
environment on the computer.
ex.) Internet, Games, Movies ...
*1 : For Analog Mode Only , *2 : For Audio Model Only.
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Q74A Service Manual
Q74ASPECIRICATIONS
▶Q74A Specifications
MODE Analog Digital
Type TFT active matrix
17 inch
Size 337.92 X 270.336 (mm)
Pixel Pitch 0.264 X 0.264 (mm)
Panel
Display Color 8-bit (16,777,216 colors)
Basic 1280x1024@60Hz Display
Resolution Maximum 1280x1024@75Hz 1280x1024@60Hz
Horizontal 31.5 ~ 80KHz 31 ~64KHz
Frequency
vertical 56 ~ 75Hz 59 ~ 61Hz
15 pin D-Sub 24pin DVI-D
Connectors Speaker Input/Headphone Output(Audio Cable) *1
Tilting Degree (U/D) -5° ~ 20° Degree
Plug&Play VESA DDC 1/2B
Input Internal type : 100~240V AC,50/60Hz, 0.5A
Consumption Under 40W (Speaker Max 4W *1)
Power
Standby mode 1W less
Power Management PowerSaver
Temperature 0~25℃ (32℉~77℉) Environmental
Consideration Humidity 90% less
Dimensions Outside 387mm * 185mm * 396mm (W*D*H)
Weight 3.9kg
*1 : For Audio Model Only
Notice
This monitor can be installed on any Plug & Play compatible system.
Interaction of the monitor and computer systems will provide the best
operating conditions and monitor settings. In most cases, monitor
installation will proceed automatically, unless the user wishes to select
alternate settings.
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Q74A Service Manual
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DISPLAY MODES
Mode Resolution
Horizontal
Frequency(KHz)
Vertical
Frequency(Hz)
Pixel Clock
(MHz)
Sync
Polarity(H/V)
720 X 400 31.468 70.087 28.322 -/+
31.468 59.940 25.175 -/-
35.000 66.670 30.240 -/-
VGA 640 X 480
37.500 75.000 31.500 -/-
37.879 60.300 40.000 +/+
48.077 72.188 50.000 +/+
SVGA 800 X 600
46.875 75.000 49.500 +/+
48.363 60.004 65.000 -/-
56.476 70.000 75.000 -/-
XGA 1024 X 768
60.023 75.029 78.750 +/+
63.981 60.020 108.000 +,-/+,-
SXGA 1280 X 1024 79.976 *1 75.025 *1 135.000 *1 +/+ *1
*1 : For Analog Mode Only.
PowerSaver
State Power
Consumption
Recovery
Time LED Color
ON Under 40W - Green
OFF Less than 1W Within 2 Sec Amber

Q74A Service Manual
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OSD MENU
▶Menu Tree
Main Menu Sub Menu Function Description
BRIGHTNESS Control of brightness
CONTRAST Control of contrast
H POSITION Control of horizontal position
V POSITION Control of vertical position
PHASE Control of phase
CLOCK Control of horizontal clock
PICTURE
AUTO ADJUST Automatic adjust position
BLUISH Color Temperature 9300k
(some blue color)
REDISH Color Temperature 6500k
(some red color)
USER RED : 0 ~ 100
GREEN : 0 ~ 100
BLUE : 0 ~ 100
COLOR
AUTO COLOR Automatic adjust color
OSD H POSI Moves the OSD Menu
OSD V POSI Moves the OSD Menu
OSD TIMER OSD display time
OSD
TRANSPARENCY OSD Transparency
LANGUAGE Select OSD language
RECALL Factory default values
INPUT SELECT DVI, ANALOG Mode Change
AUDIO Sound Mute On/Off function. *1
MISC
VOLUME You can adjust the volume. *1
*1 : For Audio Model Only

Q74A Service Manual
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FACTORY SET
OSD Menu => Misc => Recall => Yes. Every value changes factory setting value.
After factory set executes, power OFF Æpower ON automatically.
You must push the “AUTO” button because of optimum image quality automatically.
When user want factory setting value, you must execute this function.
BURN-IN MODE
If you push the down button more than 5 seconds in disconnected signal cable status, you can see changed
color.
Burn-In mode displays chaged color continually. (white, red, blue, green etc.)
We can check normal operating status of the monitor under mass production.
If you want to finish Burn-In mode, you can turn off the power by only push the power button.

Q74A Service Manual
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INVERTER & POWER
▶Inverter & POWER(Q74A)
zL.I.P.S : LCD INVERTER POWER SYSTEM(FLF1742-20A)
▶Specification
zOperate 4 CCFL Lamps.
zCurrent Feedback Control
zInput Voltage : DC 12V.
zWhen any lamp doesn’t operate, the panel is under protection status.
Protection status means that circuit protect the other lamp.
zPWM Control.
zRemote Power On/Off control
zHigh Efficiency
▶Electrical Characteristics
Description Min Typ Max Sign Remark
Input Voltage 11.0 12.0 13.0 Vin
Input Current 1.5 1.7 1.9 A 12Vdc
Output Current 5.0 6.0 7.0 mArms 1ccfl current
Lamp Frequency 40 47 55 kHz
Normal Operation ON Vin=12V
ON/OFF=5V
ON/OFF Control
Shunt-down(Lamp off) OFF Vin=12V
ON/OFF=0V
Kick-Off
Voltage MORE THAN 1100 Vrms Kick-Off

Q74A Service Manual
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▶Pin Connection
- INPUT CONNECTOR CON1
Pin NO. Symbol Descripition
1,2 VIN 1 Input Voltage : 12V
3,4,7 GND GND
5,6 VIN 2 Inopt Voltage : 5V
8 ON/OFF Power System Return
9 NC NC
- OUTPUT CONNECTOR CN1,2,3,4
Pin NO. Symbol Descripition
1 HV1,2,3,4 HI VOLTAGE TERMINAL
2 LV1,2,3,4 LOV VOLTAGE TERMINAL

Q74A Service Manual
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TROUBLESHOOTING
▶No operating at all
What you see Suggested Actions
Is the power inserted correctly? Insert the plug correctly referring to the User Manual.
Does the Power Adapter operate
correctly?
Check the Power Adapter.
The green LED is OK.
The Power Adapter operates correctly,
but the LCD Monitor does not operate
correctly.
Check the harness of the FUNC. B/D.
Does The Power On/Off and the LED
Operate corretly?
If the program of the MICOM is error, then exchange the
MICOM.
If the AD B/D is error, then exchange the AD B/D.
The Power On/Off and the LED operate
correctly, but the OSD menu doesn’t
display on screen.
First, operate the FACTORY SET.
Second, check the Panel Harness that is connected to the AD
B/D.
Check the LAMP Harness of the Panel.
Lastly, exchange the LIPS.
The OSD menu operates correctly but
the image doesn’t display on screen.
Insert the SIGNAL Cable correctly referring to the User
Manual.
Check the LAMP Harness of Panel and Inverter.
Lastly, Check the LAMP of Panel.
The Power On/Off operates correctly,
but the screen is ‘ALLWHITE’.
The LAMP is OK.
Check the Panel Harness that is connected to the AD B/D.
The Power On/Off operates correctly,
but the screen is ‘ALL BLACK’.
Check the LAMP Cable.
Check or exchange the LIPS.
Check the Panel Cable.

Q74A Service Manual
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▶Doesn’t display on LCD
“VIDEO MODE NOT
SUPPORTED” message
[Windows]
Reboot safe mode. (press the F8 key during booting).
Remove GraphicCard Driver.
Reboot normal mode.
Reinstall GraphicCard Driver.
“No signal” message Check the signal cable.
Check DPMS mode in PC.
Check pins of the signal cable.
If PC keeps DPMS status
Continually
(No signal Input,
LED color amber)
Check the signal cable.
Check pins of the signal cable.
Check HS_VGA and VS_VGA in schematics.
Doesn’t display on screen
Correctly include OSD menu
Check scaler output signal.
Check panel harness between panel andAD B/D.
Check solder status of the scaler.
Doesn’t display on screen
Correctly except OSD menu
Check the signal cable.
Check scaler input signal (RGB,H-SYNC,V-SYNC)
Noise in vertical pattern. Execute Auto Adjust.
According to graphic card.
Check 60Hz vertical frequency in display properties.
Display position error Execute Auto Adjust
Display position error occurred on dark or moving
picture.(like game)
In this case, you must execute Auto Config in windows
screen.

Q74A Service Manual
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Color error include OSD menu Check the panel harness.
Check scaler output signal.
Color error except OSD ment. Check the signal cable.
Check pins of the signal cable.
Check input/output signal of the signal cable
Key button error Check the function(key) harness.
Check the function ass’y (mechanical).
Brightness differ between upper and
lower on screen.
Because of viewing angle.

Q74A Service Manual
EXPLODE VIEW
▶Q74A
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Q74A Service Manual
PART LIST
▶Q74A Mechanical Part List
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Q74A Service Manual
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▶Q74A AD B/D Part List
Location Parts Code Parts Name Parts Spec. Remar
k
CE16 CEXF1C471A C ELECTRO 16V 470uF 20% 10x12.5 TAP
CE5,CE6,CE12,
CE13,CE14,
CE15
CEXF1C101A
C ELECTRO
16V 100uF 20% 6.3X11 TAP
CE7, CE8, CE9, CE10,
CE11
CEXF1C100A C ELECTRO 16V 10uF 20% 5x11 TAP
CON1 97E6200710 CONN WAFER 12507WR-30000 (30P LVDS)
C6, C7, C8, C10, C11,
C12, C18,C19,
C20, C21, C22, C23,
C24, C25, C26,
C27, C28, C29, C30,
C31, C34, C37,
C38, C39, C40, C41,
C42, C43, C44,
C45, C46, C47, C48, C49
HCCK104ZBA C CHIP CERA 50V 100nF Z 1608
C9 HCCH103KBA C CHIP CERA 25V 10nF K 1608
C13, C14, C15 HCCK200JBA C CHIP CERA 50V 20pF J 1608
HCCK330JBA C CHIP CERA 50V 33pF J 1608
C17 HCCK221JBA C CHIP CERA 50V 220pF J 1608
C35, C36 HCCK101JBA C CHIP CERA 50V 100pF J 1608
C32, C33 HCCK220JBA C CHIP CERA 50V 22pF J 1608
DZ1, DZ2, DZ3 ,DZ4,
DZ5, DZ6
DUDZS5.6B- ZENOR DIODE UDZS 5.6B(SOD-323), ROHS 적용품
DZ7 DZMM55C5V6 ZENER DIODE ZMM55C5V6
D2, D3, D4, D5,
D6, D7, D8,
D9, D10D11, D12, D13,
D14,D15, D16
DBAV99---- CHIP DIODE BAV99 (SOT-23)
FB4, FB5, FB7 HFA1608121 BEAD CHIP
CIM10J121NC(BEAD_120
ohm_1608)
FB3, FB6, R60 HRFS000JBA R CHIP 1/16W 0 ohm J 1608