I have one of the early sunfire subs that has had a hum problem for
some time. It seems to be in the power supply of the sub. I have the
same hum when it is not connected to the stereo and doesn't go away
when I change outlets (still unconnected) so I don't think it is a
ground loop problem.

I sm looking for some help on troubleshooting this. Does any one have
a schematic?

Thanks.

Dennis