Keyboard double typing: test before replacing.

What double typing looks like

A suspect key may produce two presses even though you intended one. Mechanical-switch chatter is one possible cause, but the browser only sees events delivered by the operating system. It cannot see the electrical contact directly.

Run a repeatable test

1. Close macro, remapping, and text-expansion software temporarily.
2. Open the Keyboard Check Lab tester and select Start test.
3. Press the suspect key normally 10–15 times. Do not intentionally double-tap at maximum speed.
4. Repeat with two known-good keys using the same rhythm.
5. Save the report and repeat in another browser. If possible, test the keyboard on another computer.

Interpret the result conservatively

A chatter candidate means the browser observed two non-repeat presses unusually close together. It is evidence worth reproducing, not proof of a defective switch. Consistent duplicates on the same key across computers are more persuasive than a single flag.

Fix the least invasive cause first

1. Reconnect the keyboard and try another USB port or cable.
2. For wireless boards, charge the battery and reduce nearby radio interference.
3. Check the manufacturer’s firmware and reset instructions.
4. Disconnect power and clean only according to the manufacturer’s guidance.
5. Replace a switch only if the keyboard is hot-swappable and you understand its compatibility and warranty implications.