James Sweet wrote:
Most of the busted speakers I've seen had mechanical problems.
Banged the volume control and broke it.
Banged the signal conector and broke it.
Dropped and cracked the circuit board.
You need either an oscilloscope or a signal injector.
mike




I don't think I've ever used either to repair speakers, usually the problem
is pretty apparent once you get it apart. A walkman is useful for supplying
a signal though, a DMM is usually sufficient for tracing.


A *finger* is often enough to supply signal (although the walkman is
higher-level, more stable approach). Touch an input and listen for hum.
Another (working) powered speaker is useful as a signal tracer
(protect the input with a small capacitor).

A DMM 'good enough' for the above can be had for $10 or less, and will
come in handy in many other situations.

jak