KEYBOARD DROPOUT TEST
Hold each key for a few seconds — a break shorter than 80 ms during the hold counts as a dropout.
Some OS key combos are captured by the system — that is expected, not a bug.
About this test
Dropout means the switch contact briefly breaks while a key is held down: the browser receives a key-up event, followed almost immediately by another key-down of the same key. The result line counts these as "Dropout events".
How it works: hold each key for a few seconds, then release. If the same key fires again within 80 ms of a release, it is counted as a dropout — a deliberate human re-press is far slower than 80 ms, so the two are easy to tell apart.
Dropout usually points to oxidized switch contacts, cold solder joints or PCB via issues; a loose hot-swap socket is another common cause. Hold keys one by one — any key with a non-zero count is your suspect.
Frequently asked questions
What is the difference between dropout and chatter?
Chatter is one press firing multiple times — usually contact bounce. Dropout is the signal briefly cutting out while you hold the key — usually a bad contact, a cold solder joint or a loose hot-swap socket. Different causes, different fixes.
How do I confirm the keyboard itself is at fault?
Re-test with a different USB port, cable and computer. If the problem follows the keyboard, it is the keyboard; if it always lands on the same key, you can narrow it down to that switch or joint.
Can I fix dropout on a hot-swap board myself?
Usually yes. Pull the switch and check for bent, oxidized or loose pins, then reseat it or drop in a new switch. On soldered boards it means re-soldering — better left to warranty service or a repair shop.