A totally dead MX Keys — no LED, no response, even plugged via USB-C — is rare but unsettling. Three causes by probability: fully discharged battery (40%), faulty motherboard (35%), internal USB-C port torn (25%). This page gives you the decision tree in 4 minutes to identify which of the three, and what each fix costs.
Diagnostic
Decision tree: Step A — plug via USB-C for at least 10 minutes. No LED? Step B. Step B — try a different cable + charger (ideally a certified 5V charger). Still nothing? Step C. Step C — press the keyboard's power button (under the spacebar on 2019 MX Keys, on the side on MX Keys S). Still dead, it is motherboard or battery. If you hear a faint click or see a brief flash: battery. If absolutely nothing: motherboard.
Méthode
- 1
Plug into USB-C for a full 30 minutes without touching the keyboard (forced charge).
- 2
Visually inspect the USB-C port with a flashlight: if a pin is bent or the port pushed into the case, it is torn.
- 3
If battery suspect: order a universal MX Keys battery (€10) and disassemble per our full guide.
- 4
If motherboard suspect: order the motherboard for your model (€15). If you are not comfortable with disassembly, contact us for a workshop return.
FAQ
How do I know whether it's the battery or motherboard?
Decisive test: hold the power button for 10 seconds while plugged via USB-C. If the LED briefly flashes after this, it was just a deeply discharged battery. If nothing happens, the motherboard is the cause.
My MX Keys fell yesterday and now won't turn on — is there hope?
Yes, in 70% of cases the motherboard remains functional after a drop. The USB-C port is often the main casualty (torn by the cable). Inspect it visually before concluding. A new €15 motherboard fixes most cases.
The keyboard was in a cold place (car in winter, accidental fridge) — should I worry?
Not immediately. Lithium-polymer batteries don't operate below 0°C. Leave the keyboard at room temperature for 4-6 hours before plugging again. In most cases the keyboard will come back to life.
A dead MX Keys is diagnosed in 4 minutes and repaired for €10-15 in 80% of cases. Before throwing it away, test the decision tree above.