Wire & connectorsRebuild shelfUnplug and unscrew

3.5 mm audio jack

Also called headphone jack, TRS, TRRS.

The headphone connector. TRS is stereo. TRRS adds a microphone and the pinout is not universal: CTIA and OMTP swap the last two rings. A jack salvaged from a known headset can be mapped once and labeled.

If you are new to this category

Wire and plugs are how power and signals move. The insulation is the safety, not the copper. Ethernet cable is fine for small signals and low voltage. It is not a substitute for a power cord. A connector you can unplug is worth more than a wire you have to solder every time.

Match the plug that came with the brick. Center-positive is common and not universal. The drawing on the label is a map: the dot is the center, the ring is the outside.

Center pin and outside sleeve

The drawing on the brick is the polarity. A dot inside a C-shaped ring means the center is positive when the plus sign points at the dot. Measure anyway. The two common hole sizes, 2.1 mm and 2.5 mm, almost fit each other and that is how the center pin gets bent.

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
TRS	Tip left, ring right, sleeve ground, on the usual stereo plug
TRRS	Confirm with the headset it came from before you build a cable

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 panel jack
A cable repair

Leave this one when

The spring contacts are bent flat. They never hold a plug again.

Buying a new one is the better idea when

A panel-mount jack. Salvage jacks are often PCB types with tiny lugs.

How to tell if this one still works

Beep from each band of a plug to the solder lug, while the plug is inserted.

Tools you will want: Meter, A known plug.

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
Powered or Bluetooth speaker	Worth it	1	usually	The aux input.
Headphones	Worth it	1	usually	The plug.

Worth pullingPowered or Bluetooth speaker1 · usually
In this particular machine
3.5 mm.
Where to look
The aux input.
How to get it out
Keep it on the board.
The condition to expect
Good.
Worth pullingHeadphones1 · usually
In this particular machine
TRS or TRRS. Map it, because headsets differ.
Where to look
The plug.
How to get it out
Cut back to fresh wire.
The condition to expect
The plug end is often the failure.