My mechanical keyboard is double-registering keystrokes on certain keys. Is this fixable or do I need new switches

[RayOfLight]

About 18 months old mechanical keyboard, Cherry MX Red switches. The E key and occasionally the spacebar are double registering, so I get ee instead of e about one in every twenty presses. Is this a dirty switch, a failing switch, or something else, and can I fix it without replacing the whole keyboard?

Keyboard is hot-swap capable

[Upsilon]

Good news: double registration on specific switches is almost always contact bounce in the switch itself, not a keyboard PCB problem. And with a hot-swap capable board you can fix individual switches without soldering

[Sparrow]

First try switch cleaning. Compressed air into the switch followed by a small amount of switch lubricant (Krytox 205g0 is the standard choice) applied via a thin applicator into the switch stem can fix contact bounce from dirty contacts

[Leo]

If cleaning does not fix it, replace just those two switches. Hot-swap means you pull the old switch out with a switch puller tool (3 to 5 pounds) and press a new one in. Cherry MX Reds are around 50p to 1 pound each bought in small quantities

[Arty Leah]

The cleaning method: power off the keyboard, use a switch opener tool to open the switch housing, clean the contact legs gently with isopropyl alcohol on a cotton bud, let it dry completely, reassemble

[Layla79]

Cherry MX switches at 18 months should not be failing from normal use. Check if liquid has ever got onto the keyboard. Even a small spill that seemed to dry out can leave residue that causes contact bounce

[TheGreatMoney]

You can also try increasing the debounce time in the keyboard firmware if your board runs QMK or Via. This tells the keyboard to wait slightly longer before registering a second keystroke and compensates for contact bounce electronically

[NicholasCleverley]

QMK firmware has a debounce setting measured in milliseconds. Default is usually 5ms. Increasing to 10 or 15ms fixes bounce-related double registration without changing the feel for fast typing

[ParallelSelf90]

Buy a switch tester pack when you replace the switches. Testing a few different switch types while you have the tools out is a good way to find out if you would prefer a different switch feel going forward

[HeartbreakKidStinger64]

18 months is young for switches to fail mechanically. If multiple switches start having the same issue soon after each other it could be a PCB trace issue rather than individual switch failure, which is a different and harder problem