Introduction
The Antec NX400 is a versatile mid-tower ATX gaming case designed for PC enthusiasts and gamers. It offers a blend of aesthetic appeal with its tempered glass side panel and ARGB lighting, alongside practical features for component installation and cooling. This manual provides essential information for setting up, operating, and maintaining your Antec NX400 case.

Figure 1: Front view of the Antec NX400 Mid-Tower ATX Gaming Case, showcasing its tempered glass side panel and front ARGB LED strip.
Key Features
- Motherboard Support: Compatible with ATX motherboards.
- Included Fan: Features 1 x 120 mm ARGB fan pre-installed in the rear for immediate cooling and lighting.
- Radiator Support: Extensive liquid cooling support with space for up to a 360 mm radiator in the front, 240 mm on top, and 140 mm in the rear.
- Drive Bays: Supports versatile storage configurations with up to 2 x 3.5" HDDs / 2.5" SSDs (convertible) and 4 x 2.5" SSDs.
- Side Panel: Equipped with a tempered glass side panel to showcase your internal components and ARGB lighting.
- Front Panel Connectivity: Includes 1 x USB 2.0 port and 2 x USB 3.0 ports for convenient peripheral connection.
- ARGB Control: Dedicated LED mode button on the front panel allows for easy cycling through various ARGB lighting effects.

Figure 2: Detail of the multi-mode ARGB light bar on the front panel and the included 120mm ARGB fan in the rear of the NX400 case.

Figure 3: The dedicated LED control button located on the top I/O panel, allowing for easy customization of ARGB effects.
Setup and Installation
Before beginning installation, ensure you have all necessary components and tools. Refer to your motherboard and component manuals for specific installation instructions.
1. Unpacking and Preparation
- Carefully remove the case from its packaging.
- Remove the tempered glass side panel by unscrewing the four thumb screws. Place it on a soft, flat surface to prevent scratches.
- Identify the included accessory box containing screws and cable ties. Note that screws may be mixed; refer to component manuals for correct screw types.
2. Motherboard Installation
- Install the I/O shield (if not pre-attached to your motherboard) into the rear opening of the case.
- Align your ATX motherboard with the pre-installed standoffs inside the case.
- Secure the motherboard using the appropriate screws (typically those with a round head and a lip).
3. Power Supply Unit (PSU) Installation
- The NX400 supports PSUs up to 170 mm in length.
- Slide the PSU into the dedicated compartment at the bottom rear of the case.
- Secure the PSU from the rear of the case using the provided screws.
4. Storage Drive Installation
- Install 3.5" HDDs or 2.5" SSDs into the drive cages located beneath the PSU shroud or behind the motherboard tray.
- The case provides dedicated mounts for up to four 2.5" SSDs.
5. Fan and Radiator Installation
- The case comes with one 120mm ARGB fan pre-installed in the rear.
- Additional fan support: Front (3 x 120mm or 2 x 140mm), Top (2 x 120mm or 2 x 140mm), Rear (1 x 120mm or 1 x 140mm).
- Radiator support: Front (up to 360mm), Top (up to 240mm), Rear (up to 140mm).

Figure 4: Diagram illustrating the fan and radiator mounting options within the Antec NX400 case.
6. Graphics Card and CPU Cooler Installation
- The case supports graphics cards up to 330 mm in length.
- CPU coolers with a maximum height of 170 mm are supported.

Figure 5: Internal layout showing maximum dimensions for CPU cooler, GPU, and PSU, along with motherboard and SSD/HDD locations.
7. Cable Management
- Utilize the cutouts and tie-down points behind the motherboard tray to route and secure cables for a clean build and improved airflow.
- Connect the front panel I/O cables (USB, audio, power, reset, LED) to the appropriate headers on your motherboard.
- Ensure the ARGB fan and front LED strip are connected. The fan typically uses a Molex connector, and the front LED strip uses a SATA power connector. These must be connected directly to your PSU.
Operation
The Antec NX400 features an intuitive front I/O panel for easy access to essential controls and ports.
Front I/O Panel
- Power Button: Press to turn the system on or off.
- Reset Button: Press to restart the system.
- LED Control Button: Cycle through various pre-programmed ARGB lighting effects for the front LED strip and the included rear fan. A single press changes the effect.
- MIC/AUDIO Jacks: Connect your headphones and microphone.
- USB 2.0 Port (x1): For connecting USB 2.0 compatible devices.
- USB 3.0 Ports (x2): For high-speed data transfer with USB 3.0 compatible devices.

Figure 6: Overview of the top-mounted I/O ports, including power, reset, LED control, audio jacks, and USB ports.
Product Overview Video
Video 1: An official product video showcasing the Antec NX400 Mid Tower Gaming Case, highlighting its design and features. (Source: PCModding)
Maintenance
Regular maintenance helps ensure optimal performance and longevity of your Antec NX400 case.
- Dust Cleaning: Periodically clean dust filters (if present) and internal components using compressed air or a soft brush. This prevents dust buildup, which can impede airflow and component cooling.
- Tempered Glass Care: Clean the tempered glass side panel with a microfiber cloth and a non-abrasive glass cleaner. Avoid harsh chemicals or abrasive materials that could scratch the glass.
- Cable Management: Occasionally check cable routing to ensure no cables are obstructing airflow or fan blades.
Troubleshooting
This section addresses common issues you might encounter with your Antec NX400 case.
1. ARGB Lighting Not Working or Incorrect Colors
- Check Connections: Ensure the front LED strip and the included ARGB fan are properly connected to their respective power sources (SATA for LED strip, Molex for fan) and to the case's internal LED controller.
- LED Button Functionality: Press the LED control button on the front I/O panel multiple times to cycle through effects. If no change occurs, verify the LED control cable is correctly connected to the motherboard or controller.
2. Excessive Fan Noise
- Included Fan: The included rear fan is connected via Molex, which typically means its speed is not controllable by the motherboard. If the fan is too loud, consider replacing it with a PWM or DC controllable fan connected to your motherboard.
- Obstructions: Check for any cables or debris obstructing fan blades.
- Mounting: Ensure all fans are securely mounted to prevent vibrations.
3. Front Panel USB/Audio Ports Not Functioning
- Internal Connections: Verify that the USB and audio cables from the front I/O panel are securely connected to the correct headers on your motherboard. Refer to your motherboard manual for header locations.
4. Missing or Mixed Screws
- The case includes a single bag with various screw types. Refer to your component manuals (motherboard, PSU, drives) to identify the correct screws for each part. Common types include screws for motherboard standoffs (round head with lip), PSU mounting, and drive installation.
Technical Specifications
| Feature | Specification |
|---|---|
| Model Name | NX400 |
| Case Type | Mid Tower |
| Motherboard Compatibility | ATX |
| Dimensions (L x W x H) | 20 x 11 x 19 inches (508 x 279.4 x 482.6 mm) |
| Item Weight | 13.86 pounds (6.28 kg) |
| Materials | SPCC + Plastic |
| Front I/O Ports | 1 x USB 2.0, 2 x USB 3.0, MIC/AUDIO, Power, Reset, LED Control Button |
| Included Fans | 1 x 120 mm ARGB fan (rear) |
| Max GPU Length | 330 mm |
| Max CPU Cooler Height | 170 mm |
| Max PSU Length | 170 mm |
| Drive Bays | 2/1 x 3.5" HDD / 2.5" SSD, 4 x 2.5" SSD |
| Cooling Method | Air |
| Light Color | Multi-color (ARGB) |
Warranty and Support
For warranty information, technical support, or service inquiries regarding your Antec NX400 case, please refer to the official Antec website or contact Antec customer support directly. Keep your proof of purchase for warranty claims.
Official Antec Website: www.antec.com





