1. Introduction
This manual provides comprehensive instructions for the setup, operation, maintenance, and troubleshooting of your BenQ TH671ST 1080p Short Throw Gaming Projector. Please read this manual thoroughly before using the product to ensure proper functionality and to maximize your viewing and gaming experience.
2. Safety Information
Always follow basic safety precautions when using this product to reduce the risk of fire, electric shock, and injury to persons. Keep the projector away from water or moisture. Do not block ventilation openings. Refer to the full safety guidelines in the included Quick Start Guide or User Manual CD for detailed information.
3. What's in the Box
- Remote Control w/ Battery
- Power Cord
- User Manual (on CD)
- Quick Start Guide
- Warranty Card
- VGA (D-sub 15pin) Cable
- Lens Cover
- AAA Batteries (x2)
4. Product Overview
The BenQ TH671ST is a 1080p short throw gaming projector designed for immersive cinematic and gaming experiences. It features high brightness and low input lag for optimal performance.

Figure 1: Front view of the BenQ TH671ST projector.
Key Features:
- Unparalleled Picture Quality: Native Full HD 1080p Resolution, 92% Rec. 709 Color Accuracy, 3000 Lumens, and a high native contrast ratio for an immersive experience.
- Geared Towards Gaming: Ultra-fast low input lag (16.7ms at 1080p@60Hz) and a refresh rate matching Xbox One X & PS4 Pro for ultra-smooth gaming without motion blur.
- Large Screen Projection: Project a 100-inch screen from just 5 feet away, with projection capabilities up to 300 inches.
- Integrated Audio: Features a 5W built-in speaker.

Figure 2: Overview of key features for the BenQ TH671ST projector.
Dimensions and Weight:
The projector measures approximately 11.65 x 4.6 x 9.5 inches (W x H x D) and weighs 5.9 pounds (2.7 kg).

Figure 3: Physical dimensions of the BenQ TH671ST projector.
5. Setup
5.1 Physical Placement
The BenQ TH671ST is a short throw projector, allowing for large images from a short distance. For example, it can project a 100-inch image from approximately 5 feet (1.5 meters) away. The projector supports image sizes from 30 inches up to 300 inches diagonally.

Figure 4: Recommended projection distances for various screen sizes.
5.2 Connections
The projector offers a variety of input and output ports for versatile connectivity:
- HDMI: Two HDMI ports (HDMI-1 (1.4a), HDMI-2 (1.4a/MHL/HDCP1.4)) for digital video and audio input.
- PC (D-Sub): One VGA input for computer connection.
- Monitor Out (D-Sub): One VGA output for connecting an external monitor.
- USB Type A: One USB 2.0 port for power supply (e.g., for streaming dongles).
- USB Type mini B: One port for service.
- Audio In (3.5mm Mini Jack): One port for external audio input.
- Audio Out (3.5mm Mini Jack): One port for external audio output.
- RS232 (DB-9pin): One port for serial control.
- IR Receiver: Two receivers (Front & Top) for remote control.

Figure 5: Universal connectivity ports on the BenQ TH671ST.
5.3 Mounting
The projector can be placed on a table or ceiling-mounted. If ceiling-mounted, ensure the image orientation is adjusted in the projector's menu settings (Front Ceiling or Rear Ceiling options).
Video 1: Official BenQ video demonstrating the TH671ST projector's features and setup options.
6. Operating Instructions
6.1 Power On/Off
Use the power button on the projector or the remote control to turn the unit on or off. Allow a few moments for the projector to warm up or cool down.
6.2 Picture Modes
Select from various picture modes to optimize your viewing experience:
- Bright
- Vivid TV
- Cinema
- Sport
- Game
- User 1
- User 2
- 3D

Figure 6: Various sound modes available on the projector.
6.3 Audio Settings
The projector includes a 5W speaker. Adjust volume and other audio settings via the remote control or on-screen menu. For enhanced audio, connect external speakers to the Audio Out port.
6.4 Keystone Adjustment
The projector supports 1D Vertical Keystone adjustment of +/- 40 degrees to correct distorted images when the projector is not perfectly perpendicular to the screen.

Figure 7: Automatic vertical keystone correction in action.
6.5 Zoom and Focus
Adjust the zoom (1.2x) and focus manually using the rings on the projector lens to achieve a clear and sharp image at your desired screen size.
6.6 Remote Control Usage
The included remote control allows for easy navigation of menus, input selection, volume control, and picture adjustments. Ensure batteries are correctly inserted.
Video 2: Official BenQ video highlighting the low input lag performance of the TH671ST, ideal for gaming.
7. Maintenance
7.1 Lamp Life
The projector's lamp has an estimated life of:
- Normal Mode: 4000 hours
- Economic Mode: 10000 hours
- SmartEco Mode: 10000 hours
- Lampsave Mode: 15000 hours
Actual lamp life may vary based on usage and environmental conditions.
7.2 Cleaning
Regularly clean the projector lens with a soft, lint-free cloth. Ensure ventilation vents are free from dust and obstructions to prevent overheating.
8. Troubleshooting
If you encounter issues with your projector, refer to the following general troubleshooting steps:
- No Image: Check power connections, input source selection, and cable connections.
- Blurred Image: Adjust the focus ring on the lens. Ensure the projector is within the recommended projection distance.
- Distorted Image: Use the keystone correction feature to adjust the image shape.
- No Sound: Check volume settings, ensure external audio devices are properly connected, and verify the audio output setting.
- Overheating: Ensure adequate ventilation around the projector and clean any dust from the vents.
For more detailed troubleshooting, consult the full User Manual CD or contact BenQ customer support.
9. Specifications
| Display System | DLP |
| Resolution | 1080p (1920x1080) |
| Brightness (ANSI lumens) | 3000lm |
| Contrast Ratio (FOFO) | 10000:1 |
| Light Source | Lamp (240W) |
| Throw Ratio | 0.69~0.83 (100"@1.5m) |
| Zoom Ratio | 1.2x |
| Keystone Adjustment | 1D, Vertical +/- 40 degrees |
| Image Size (Diagonal) | 60"~120" (Clear), 30"~300" (Max) |
| Speaker | 5W x 1 |
| Connectivity | HDMI (x2), PC (D-Sub), Monitor Out (D-Sub), USB Type A, USB Type mini B, Audio In/Out, RS232 |
| Power Supply | AC 100 to 240 V, 50/60 Hz |
| Dimensions (W x H x D) | 296 x 120 x 224 mm (11.65 x 4.72 x 8.82 inches) |
| Net Weight | 2.7 kg (5.95 lbs) |
10. Warranty and Support
The BenQ TH671ST projector comes with a 3-year limited parts and labor coverage. For warranty claims or technical assistance, please refer to the Warranty Card included in your product packaging or visit the official BenQ support website.





