BenQ Th681 Digital Projector User Manual

							TH681
Digital Projector
User Manual 
						

							Table of contents 2
Ta b l e  o f  c o n t e n t s
Important safety 
instructions ........................... 3
Introduction .......................... 7
Projector features ..................................... 7
Shipping contents ...................................... 8
Projector exterior view........................... 9
Controls and functions ..........................10
Positioning your 
projector.............................. 13
Choosing a location ................................13
Obtaining a preferred projected image 
size ..............................................................14
Connection ......................... 16
Connecting video source devices........17
Operation ............................ 18
Starting up the projector ......................18
Adjusting the projected image .............19
Using the menus ......................................21
Securing the projector ...........................22
Switching input signal .............................24
Magnifying and searching for details ...25
Selecting the aspect ratio ......................25
Optimizing the image .............................27
Setting the presentation timer .............30
Remote paging operations ....................31
Freezing the image ..................................31
Hiding the image......................................32
Locking control keys ..............................32
Operating in a high altitude 
environment .............................................32
Adjusting the sound ................................33
Using the test pattern ............................33Using the teaching templates ............... 34
Shutting down the projector ............... 35
Direct power off ..................................... 35
Menu operation ...................................... 36
Maintenance ........................ 46
Care of the projector ............................ 46
Lamp information ................................... 47
Troubleshooting ................ 53
Specifications ...................... 54
Projector specifications ......................... 54
Dimensions .............................................. 55
Ceiling mount installation ..................... 55
Timing chart ............................................. 56
Warranty and Copyright 
information ......................... 60 
						

							Important safety instructions 3
Important safety instructions
Your projector is designed and tested to meet the latest standards for safety of information 
technology equipment. However, to ensure safe use of this product, it is important that 
you follow the instructions mentioned in this manual and marked on the product. 
Safety Instructions
1.Please read this manual before 
you operate your projector. Save 
it for future reference. 
2.Do not look straight at the 
projector lens during operation. 
The intense light beam may damage 
your eyes. 
3.Refer servicing to qualified 
service personnel. 
4.Always open the lens shutter (if 
any) or remove the lens cap (if 
any) when the projector lamp is 
on. 5. In some countries, the line voltage is 
NOT stable. This projector is 
designed to operate safely within a 
mains voltage between 100 to 240 
volts AC, but could fail if power cuts 
or surges of ±10 volts occur. In 
areas where the mains voltage 
may fluctuate or cut out, it is 
recommended that you connect 
your projector through a power 
stabilizer, surge protector or 
uninterruptible power supply 
(UPS). 
6. Do not block the projection lens with 
any objects when the projector is 
under operation as this could cause 
the objects to become heated and 
deformed or even cause a fire. To 
temporarily turn off the lamp, press 
ECO BLANK on the projector or 
remote control. 
						

							Important safety instructions 4
  
Safety Instructions (Continued)
7. The lamp becomes extremely hot 
during operation. Allow the projector 
to cool for approximately 45 minutes 
prior to removing the lamp assembly 
for replacement. 
8. Do not operate lamps beyond the 
rated lamp life. Excessive operation of 
lamps beyond the rated life could 
cause them to break on rare 
occasions. 
9. Never replace the lamp assembly or 
any electronic components unless the 
projector is unplugged. 10. Do not place this product on an 
unstable cart, stand, or table. The 
product may fall, sustaining serious 
damage. 
11. Do not attempt to disassemble this 
projector. There are dangerous high 
voltages inside which may cause death 
if you should come into contact with 
live parts. The only user serviceable 
part is the lamp which has its own 
removable cover.
Under no circumstances should you 
ever undo or remove any other 
covers. Refer servicing only to 
suitably qualified professional service 
personnel.
12. When the projector is under 
operation, you may sense some 
heated air and odor from its 
ventilation grill. It is a normal 
phenomenon and not a product 
defect. 
						

							Important safety instructions 5
    
Safety Instructions (Continued)
13. Do not place this projector in any of 
the following environments.
- Space that is poorly ventilated or 
confined. Allow at least 50 cm 
clearance from walls and free flow of air 
around the projector. 
- Locations where temperatures may 
become excessively high, such as the 
inside of a car with all windows rolled 
up.
- Locations where excessive humidity, 
dust, or cigarette smoke may 
contaminate optical components, 
shorten the projectors life span and 
darken the image.
- Locations near fire alarms
- Locations with an ambient temperature 
above 40°C / 104°F
- Locations where the altitudes are higher 
than 3000 m (10000 feet).
14. Do not block the ventilation holes.
- Do not place this projector on a 
blanket, bedding or any other soft 
surface.
- Do not cover this projector with a cloth 
or any other item.
- Do not place inflammables near the 
projector. 
If the ventilation holes are seriously 
obstructed, overheating inside the 
projector may result in a fire.
15. Always place the projector on a level, 
horizontal surface during operation.
- Do not use if tilted at an angle of more 
than 10 degrees left to right, nor at 
angle of more than 15 degrees front to 
back. Using the projector when it is not 
fully horizontal may cause a malfunction 
of, or damage to, the lamp. 
16. Do not stand the projector on end 
vertically. Doing so may cause the 
projector to fall over, causing injury or 
resulting in damage to the projector.
3000 m
(10000 feet)
0 m
(0 feet) 
						

							Important safety instructions 6
Safety Instructions (Continued)
17. Do not step on the projector or place 
any objects upon it. Besides probable 
physical damage to the projector, doing 
so may result in accidents and possible 
injury.
18. Do not place liquids near or on the 
projector. Liquids spilled into the 
projector may cause it to fail. If the 
projector does become wet, 
disconnect it from the power supplys 
power outlet and call BenQ to have 
the projector serviced.
19. This product is capable of displaying 
inverted images for ceiling mount 
installation.
Use only BenQs Ceiling Mount Kit for 
mounting the projector and ensure it is 
securely installed.
20. This apparatus must be earthed.
Ceiling mounting the projector
We want you to have a pleasant 
experience using your BenQ projector, 
so we need to bring this safety matter 
to your attention to prevent possible 
damage to person and property.
If you intend to mount your projector 
on the ceiling, we strongly recommend 
that you use a proper fitting BenQ 
projector ceiling mount kit and that 
you ensure it is securely and safely 
installed.
If you use a non-BenQ brand projector 
ceiling mount kit, there is a safety risk 
that the projector may fall from the 
ceiling due to an improper attachment 
through the use of the wrong gauge or 
length screws.
You can purchase a BenQ projector 
ceiling mount kit from the place you 
purchased your BenQ projector. BenQ 
recommends that you also purchase a 
separate Kensington lock compatible 
security cable and attach it securely to 
both the Kensington lock slot on the 
projector and the base of the ceiling 
mount bracket. This will perform the 
secondary role of restraining the 
projector should its attachment to the 
mounting bracket become loose.
Hg - Lamp contains mercury. Manage in 
accordance with local disposal laws. See 
www.lamprecycle.org. 
						

							Introduction 7
Introduction
Projector features
The projector offers the following features
• Full HD compatible
The projector is compatible with Standard Definition TV (SDTV) 480i, 480p, 576i, 576p 
and High Definition TV (HDTV) 720p, 1080i and 1080p formats, with the 1080p format 
providing a true 1:1 image reproduction.
• SmartEco™ starts your dynamic power saving
The SmartEco™ technology offers a new way of operating the projector lamp system 
and saves lamp power depending on the content brightness level.
• Longest lamp life with SmartEco™ technology
The SmartEco™ technology lowers the power consumption and increases the lamp 
life.
• ECO BLANK saves the lamp power
Pressing the ECO BLANK button to hide the image and immediately lower the lamp 
power at the same time.
• Less than 0.5W in standby condition
Less than 0.5W power consumption under standby mode.
• Quick Cooling, Auto Power Off, Signal Power On, Direct Power On
Quick Cooling function speeds up the cooling process when turning off the 
projector. Auto Power Off function allows the projector to turn off automatically if 
no input signal is detected after a set period of time. Signal Power On function turns 
on your projector automatically once detecting the signal input and Direct Power 
On boots up the projector automatically when the power is connected.
• Instant Restart
Selectable Instant Restart function enables you to restart the projector immediately 
within 90 seconds after turning it off.
• 3D Function supported
Various 3D formats make the 3D function more flexible. By presenting the depth of the 
images, you can wear BenQ 3D glasses to enjoy the 3D movies, videos and sporting 
events in a more realistic way.
•  The apparent brightness of the projected image will vary depending on the ambient lighting conditions, 
selected input signal contrast/brightness settings, and is directly proportional to projection distance.
•  The lamp brightness will decline over time and may vary within the lamp manufacturers specifications. This 
is normal and expected behavior. 
						

							Introduction 8
Shipping contents
Carefully unpack and verify that you have all of the items shown below. If any of these items 
are missing, please contact your place of purchase.
Standard accessories
The supplied accessories will be suitable for your region, and may differ from those illustrated.
*The warranty card is only supplied in some specific regions. Please consult your dealer for detailed 
information.
Optional accessories
1. Spare lamp kit
2. Ceiling mount kit
3. Carry bagProjector Power cord VGA cable
Quick start guide User manual CD Warranty card*
Remote control with batteries
 
Digital ProjectorQuick Start Guide 
						

							Introduction 9
Projector exterior view
1. External control panel
(See Controls and functions on page 10 
for details.)
2. Lamp cover
3. Vent (heated air exhaust)
4. Quick-release button
5. Lens cap
6. Focus and Zoom ring
7. Vent (cool air intake)
8. Speaker grill
9. Front IR remote sensor
10. Projection lens
11. RS232 control port
12. USB port
13. HDMI-input port
14. RGB signal output jack
15. RGB (PC)/Component Video (YPbPr/ 
YCbCr) signal input jack
16. S-Video input jack
Video input jack
17. Audio (L/R) input jacks
18. Audio input jack
19. Audio output jack
20. Kensington anti-theft lock slot
21. AC power jack
22. Rear adjuster foot
23. Ceiling mount holes
5
2
1
3
48
6
7
10
9
Front/upper side
131112141516171819
20
22
21
23
Rear/lower side 
						

							Introduction 10
Controls and functions
Projector
1. Focus ring
Adjusts the focus of the projected image.
2. Zoom ring
Adjusts the size of the image.
3. Top IR remote sensor
4. MENU/EXIT
Turns on the On-Screen Display (OSD) 
menu. Goes back to previous OSD menu, 
exits and saves menu settings.
5. POWER
Toggles the projector between standby 
mode and on.
6.  Left/
Decreases the projector volume.
7. MODE/ENTER
Selects an available picture setup mode.
Activates the selected On-Screen Display 
(OSD) menu item.
8. ECO BLANK
Used to hide the screen picture.
9. POWER indicator light
Lights up or flashes when the projector is 
under operation.
10. TEMPerature warning light
Lights up red if the projectors 
temperature becomes too high.11. LAMP indicator light
Indicates the status of the lamp. Lights up 
or flashes when the lamp has developed a 
problem.
12. AUTO
Automatically determines the best picture 
timings for the displayed image.
13. Keystone/Arrow keys ( / Up,  /
Down)
Manually corrects distorted images 
resulting from an angled projection.
14. Right/
Increases the projector volume.
When the On-Screen Display (OSD) 
menu is activated, the #6, #13, and #14 
keys are used as directional arrows to 
select the desired menu items and to 
make adjustments.
15. SOURCE
Displays the source selection bar.
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3
6
4
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