Altec Lansing making noise when on and not playing a song

michaelsol

Estimable
Sep 25, 2015
3
0
4,510
Hi everyone,

I bought many years ago a Altec Lansing ATP3 speaker set for the computer and had it stored for many years. Now I am using it again I am surprised by the loud noise that the speakers make while on but no sound being played.
When some music is played, if louder then the noise, I don't hear it anymore but if not loud enough, the noise is still there.
I noticed that the noise is slightly louder when the computer is connected to the outlet.

What could it be? Would it be resolved by adding a grounding cable to the speakers???
Any other solutions?

Thank you