Keep-whole modulesKeep the moduleHand tools, works as-is

Amplifier board

Also called class D, PAM8403, TPA3116, speaker board.

The board in a set of powered speakers or a Bluetooth speaker, between the input jack and the drivers. Often a class-D chip that is happier left on its board with its inductors than desoldered into a project.

If you are new to this category

Some scrap is already a finished object: a webcam a computer recognizes, a barcode scanner that types numbers, an amplifier board between a jack and a speaker. Opening these to pull a chip almost always throws away the useful thing. If it still works when you plug it in, stop there.

Test the whole module before you unscrew it. A working webcam is worth more than the parts inside a dead one.

Stop when it still works

Plug the module in before you take it apart. A webcam the computer already sees, a scanner that types into a text box, or a speaker board that plays music is the finished part. The chips on the board are not an upgrade.

Mains voltage. Line voltage, and the DC bus just after the rectifier, both kill. A disconnected cord is not a discharged supply.

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
Supply	Printed near the connector, or inferred from the brick. 5 V PAM-class boards are common in small sets; larger boards want 12–24 V.
Load	Match the speaker impedance it came with

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 speaker you are keeping
A small bench amp

Leave this one when

A burnt inductor or a cracked chip. Class-D failures are often visible.

Buying a new one is the better idea when

A module with screw terminals, if this board's connector is a mystery flex.

How to tell if this one still works

Correct supply, correct speaker, a known audio source at low volume. DC on the output (meter, no speaker) should be near zero.

Tools you will want: Meter, The original supply.

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	Prize	1	usually	The active cabinet.
Clock radio or stereo	Worth it	1	usually	Main board or a module.

Prize — take this firstPowered or Bluetooth speaker1 · usually
In this particular machine
Class D, supply printed on the board or implied by the brick.
Where to look
The active cabinet.
How to get it out
Keep the input jack.
The condition to expect
Hum means filter caps.
Worth pullingClock radio or stereo1 · usually
In this particular machine
A small audio amp. On old sets it may be discrete.
Where to look
Main board or a module.
How to get it out
Keep the heatsink.
The condition to expect
Scratchy pots are separate.