Switching & protectionBench electronicsUnplug and unscrew

Mechanical keyswitch

Also called Cherry MX, keyboard switch.

Only worth pulling from an actual mechanical keyboard. Membrane keyboards do not contain these, no matter how 'clicky' the marketing was.

If you are new to this category

A switch opens or closes a circuit. Some switches are for your finger. Some open when they get too hot and stay open. Those do not reset. A relay is a switch that a small current turns on so it can control a larger current. Use the rating printed on the part.

Click it and listen. Then use a meter on continuity, which beeps when the contacts touch. Do not guess that a small switch can run a motor.

The three legs of a snap switch

Common is the moving contact. NO means normally open: that leg connects only while you press. NC means normally closed: that leg is connected until you press. Click the button while the meter is on continuity and write down which beep matches which leg.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Footprint	MX-style cross stem is the common salvage. Alps and others show up in older boards and do not interchange.
Pins	2, plus a plastic pin. The diode is on the board, not in the switch.
Life	Tens of millions on genuine parts. A board is usually scrapped for a dead controller or a spilled drink, not worn switches.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

A hand-wired pad
Replacing one dead switch in another board of the same family

Leave this one when

The plate is riveted and you will destroy more switches than you save. Drink damage that reached the contacts is also a no.

Buying a new one is the better idea when

A bag of new switches. Pull these only if the board is already open and they are a type you like.

How to tell if this one still works

Beep across the pins while you press. Intermittent means corrosion; bin it.

Tools you will want: Soldering iron, Desolder pump.

Where people actually find it

2 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Keyboard	Prize	60–100	sometimes	Only on a mechanical board.
Laptop	Leave it	many	sometimes	Only on the rare laptop that used real mechanical switches. Almost all are membranes.

Prize — take this firstKeyboard60–100 · sometimes
In this particular machine
MX-style or similar, two pins.
Where to look
Only on a mechanical board.
How to get it out
Desolder. Test each, because spills are uneven.
The condition to expect
Excellent when dry.
Leave it — present, not yours to reuseLaptopmany · sometimes
In this particular machine
A membrane is not a keyswitch.
Where to look
Only on the rare laptop that used real mechanical switches. Almost all are membranes.
How to get it out
Do not desolder a membrane looking for switches.
The condition to expect
Worn.