SVS issues

[koover]

I have a 2 sub system. A SVS and a Def Tech Supercube 1

My SVS PB12 NSD isn't really working. It rarely comes on where the front Def Tech is always firing on all cylinders.
The green power light is never on either on the SVS. Periodically it'll turn on but it's far and few in between working. When the green power light does come on, it doesn't work at all. I'm educated enough to know that a film is encoded to fire up the sub when it's called for but that's not the issue. It just doesn't work at all when the light stays on. Then of course the green power goes off and doesn't come back on after I get done messing with it. It doesn't work when it's toggled in the auto or on position. I've touched nothing at all other then what I've already stated and all connections seem to be secure

The rest of the system works perfectly fine except.......
.
Very close to the same time the SVS went out, the supercube acquired a hum. When I fiddle with the volume control knob in the back and turn it to zero, then back up to where I have it set and calibrated to, the hum will go away. At least for a while where ill then have to go through the entire process again to eliminate the hum.

Seems odd that both subs all of a sudden acquire issues close to the same time.
I know this is pretty general and vague but I'm hoping someone has an idea or two as to why this would happen.
The rest of my system is in my sig.

Thanx for any hopeful upcoming responses.