The menu key is a special function that switches to a different layer and is processed locally on the PCB. Most key testers will not be able to detect it as it does not send any key codes to your computer. To correctly test your PCB:
...
dropdown menu, enable Test Matrix mode
, then test each key on your PCB.Key Tester
tab, enable Test Matrix
, then test each key on your PCB.When your PCB is not being detected by your computer, this could be caused by a variety of factors. We begin troubleshooting with a simple check of the USB cable and USB ports to ensure the issue is not with the computer or USB cable. If the PCB is not defective and the firmware is simply corrupted or the PCB does not have a firmware installed, your computer may not recognize the keyboard — in this situation, putting your PCB into DFU mode (also referred to as reset mode) will allow QMK Toolbox to detect your PCB. Use QMK Toolbox to flash the PCB with its firmware. When these two troubleshooting steps don't work, a hardware issue likely exists on the daughterboard, JST cable, or the PCB and further troubleshooting will be required to determine the cause.
When a single switch is not working, this usually means the PCB is fine and self-repair is relatively simple and easy to do.
Try flashing the firmware for your PCB again using QMK Toolbox.
Most keyboard PCBs do not connect each key individually to the microcontroller; instead, a matrix is used and each key belongs to a specific row and column. A key is considered activated when electricity is flowing through its column and row. When an entire row of keys fail to register any key inputs, it is typically caused by physical damage to the PCB traces — the copper lines that connect each key to the one above and below may have been severed, preventing electricity from flowing through the column and causing the PCB to not be able to detect any of the keys in the column.
Try flashing the firmware for your PCB again using QMK Toolbox.
Most keyboard PCBs do not connect each key individually to the microcontroller; instead, a matrix is used and each key belongs to a specific row and column. When an entire row of keys are activated together, it generally means the PCB is shorting against the bottom case. A short means that electricity is flowing between the switch pins unintentionally, causing the PCB to think that a switch is being pressed even when it isn't.
When a row of keys stop working, this suggests a hardware defect either caused by a damaged horizontal-trace or microcontroller. When this happens, the PCB needs to be replaced.
Check to ensure that you have flashed the correct firmware. Some PCBs have different firmwares for their solder and hotswap variants which can cause the keymap to appear scrambled, usually with each key appearing one or two positions to the right or left of where it normally belongs.
When a switch is pressed once but it inputs multiple times to your computer, it is typically caused by a damaged contact-leaf inside the switch or a loose connection between the electrical switch pins and the hotswap socket.
This guide is a work-in-progress and we are constantly adding to this as new troubleshooting methods are found. Feel free to join our server for help from community members, or to contribute to this troubleshooting guide.