Re: alternator whining noise

[Lars Arvidsson <arvid@xxxxxxx>]

Try this:
Get an old scrapped AM radio, inside you'll probably find a thing called

a ferrite core, it's slightly thicker than a pencil, and abt. 3" to 7"
long.
It has wires wounded around it, called coils, pull those of the core, so
you get a
clean ferrite core, it's black cylinder or has a rectangular
crosssection, feels like it's ceramic

This thing we will use in this manner:
Take the positive lead to the car stereo and wound it around the core,
as many turns as you have wire to.
abt. 10-20 turrns should do it.Put it as close to the car stereo as
possible.Secure the windings with tape, for instance.
In severe cases, it is recommended to try to wound both the positive and
the ground wire around the core.

This will make a what's called a low-pass filter, the interference from
the alternator will not pass your coil,
but the DC will.

Good luck
Lars Arvidsson, Alfa 75 T.S. 1990
[arvid@domain.elided] or [lars.arvidsson@domain.elided]

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