LightingYou will see this often

Flashlight

Also called torch, headlamp.

A LED, a switch, a lens, and sometimes an 18650. The valuable version is the one that took a real cell. Keychain lights are a coin cell and a disappointment.

A donor is the dead machine. The parts below are what is still worth removing from it. “Leave it” is a part that is physically in there and should stay in there: too dangerous, too worn, or only useful as part of a repair you are not doing.

What you are looking at

A scrapped machine is a box of parts that failed at different times. The reason it was thrown out is often one bad piece. The motor, the cord, the supply, and the screws are frequently still good. This index says which is which.

Why it is in the trash while the parts are not

Corroded alkaline cells, or a lost charger. The LED rarely dies first.

Before you open it

Do this while it is still unplugged, cool, and not leaking. Cells out. Alkaline leaks are corrosive. Lithium cells get tape on the end.

Lithium-ion cells

Where the dead machine usually is

Junk drawer and cable box — In the house
Garage and shed — In the house

The drawer, with the cells still in it, leaking.

How it comes apart

Tail cap. Do not short the cell against the spring while you are holding it.

Tools: Hands, Meter.

What to take

The table is the short version. The notes under it describe that part inside this machine, not only the general description.

Parts in this donor
Part	Call	How many	How often	Where to look
LED array or COB	Prize	1	usually	The head.
LED constant-current driver	Worth pulling	1	sometimes	Behind the star.
Cylindrical lithium-ion cell	Worth pulling	1	sometimes	The body.
Panel switch	Worth pulling	1	usually	The tail.
Lens and optical glass	Bonus	1	always	The bezel.
Spring	Worth pulling	2	always	Head and tail.
Enclosure	Bonus	1	always	The tube.

Prize

Prize — take this firstLED array or COB1 · usually
One white LED on a star, or a small COB.
The head.
The star is the heatsink.
Good.

Worth pulling

Worth pullingLED constant-current driver1 · sometimes
AMC7135 boards show up in hobby lights. Cheap lights use a single resistor or a mystery boost.
Behind the star.
Read the chip.
Good.
Worth pullingCylindrical lithium-ion cell1 · sometimes
18650, sometimes unprotected.
The body.
Test it. A light left on flattens it.
Mixed.
Worth pullingPanel switch1 · usually
A clicky switch.
The tail.
These are useful and annoying to replace.
Contact wear.
Worth pullingSpring2 · always
Battery contacts.
Head and tail.
Clean corrosion.
Good.

Bonus

Bonus, if you are already in thereLens and optical glass1 · always
Plastic or glass, plus a reflector.
The bezel.
Keep the reflector with it.
Scratched.
Bonus, if you are already in thereEnclosure1 · always
An aluminum tube.
The tube.
A ready enclosure for a small project of the same shape.
Dented threads are the end.