Keychron K4 QMK Wireless Custom Mechanical Keyboard User Manual

Introduction

This manual provides comprehensive instructions for the Keychron K4 QMK Wireless Custom Mechanical Keyboard (Version 3). It covers setup, operational procedures, maintenance guidelines, and product specifications to ensure optimal use and longevity of your device. The Keychron K4 is a 96% layout (100-key) mechanical keyboard featuring QMK firmware for extensive customization, dual wireless (Bluetooth 5.1 and 2.4G) and wired (USB-C) connectivity, and a white backlight.

Image: The Keychron K4 keyboard positioned on a wooden desk, showcasing its compact 96% layout.

Package Contents

Verify that all items are present in the package:

• Keychron K4 QMK Wireless Custom Mechanical Keyboard
• USB-C to USB-A Cable
• Keycap Puller
• Switch Puller (if hot-swappable version)
• User Manual

Setup

1. Operating System Switch

Locate the OS switch on the side or back of the keyboard. Toggle it to the appropriate position for your operating system (Windows/Android or macOS).

Image: A detailed view of the physical switch on the keyboard used to select between Windows/Android and macOS operating system modes.

2. Connectivity Modes

The Keychron K4 supports three connectivity options: Bluetooth, 2.4G Wireless, and USB-C wired.

• Bluetooth Mode: Slide the mode switch to 'BT'. To pair, press and hold 'Fn + 1' (or 'Fn + 2' / 'Fn + 3') for 4 seconds until the indicator light flashes rapidly. Select 'Keychron K4' from your device's Bluetooth settings. The keyboard can connect to up to three devices simultaneously.
• 2.4G Wireless Mode: Slide the mode switch to '2.4G'. Insert the 2.4G receiver into your device's USB port. The keyboard should connect automatically.
• USB-C Wired Mode: Slide the mode switch to 'Cable'. Connect the provided USB-C cable from the keyboard to your computer.

Image: The Keychron K4 keyboard demonstrating its ability to connect to multiple devices, including a laptop, desktop monitor, and tablet, via wireless technology.

3. Charging the Battery

The keyboard is equipped with a 4000mAh lithium-ion battery. Connect the USB-C cable to the keyboard and a power source (computer USB port or wall adapter) to charge. The charging indicator light will show the charging status.

Image: The Keychron K4 keyboard on a wooden surface, highlighting its 4000mAh battery capacity.

Operating Instructions

1. Key Customization with QMK and Keychron Launcher

The Keychron K4 features QMK firmware, allowing for extensive key remapping, macro creation, and custom shortcuts. Utilize the Keychron Launcher web application to easily customize each key. Visit the official Keychron website for access to the Launcher and detailed instructions.

Image: A visual representation of the Keychron Launcher software, displaying its interface for customizing keyboard keymaps and functions.

2. Backlight Control

The keyboard features a white backlight. Use the dedicated backlight key (often 'Fn + Light bulb icon' or similar) to cycle through various lighting effects and brightness levels. Refer to the keyboard's keycap legends for specific backlight control shortcuts.

Image: A close-up view of the Keychron K4 keyboard's keys illuminated by its white backlight.

3. Ergonomic Support

The Keychron K4 is designed with two-level adjustable feet and an inclined bottom frame to provide ergonomic support and comfort during extended typing sessions. Adjust the feet to your preferred typing angle.

Image: A side profile of the Keychron K4 keyboard, illustrating the two adjustable feet positions for ergonomic typing angles.

Maintenance

1. Cleaning

To clean your keyboard, first disconnect it from all power sources. Use a soft, lint-free cloth slightly dampened with water or a mild cleaning solution. For deeper cleaning, use the provided keycap puller to remove keycaps and clean underneath with compressed air or a small brush. Avoid excessive moisture.

2. Battery Care

To prolong battery life, avoid fully discharging the keyboard frequently. Store the keyboard in a cool, dry place when not in use for extended periods. If the keyboard will not be used for a long time, charge it to approximately 50% before storage.

Image: An exploded diagram illustrating the internal components of the Keychron K4 keyboard, including keycaps, switches, plate, foam, PCB, and battery.

Troubleshooting

• Keyboard not connecting via Bluetooth: Ensure the OS switch is set correctly. Turn off and on the keyboard. Delete the keyboard from your device's Bluetooth list and re-pair. Ensure the keyboard is charged.
• Keys not responding: Check if the keyboard is in the correct mode (wired/wireless). If in wired mode, ensure the USB-C cable is securely connected. If wireless, check battery level.
• Backlight not working: Ensure the backlight is enabled and brightness is adjusted. Check battery level.
• Lag or input delay: Ensure the keyboard is within range of your device for wireless connections. For wired connections, try a different USB port or cable.

Specifications

Warranty and Support

Keychron products typically come with a limited manufacturer's warranty. For specific warranty terms, technical support, or service inquiries, please refer to the official Keychron website or contact their customer support directly. Keep your proof of purchase for warranty claims.

Official Keychron Website: www.keychron.com