Help with Infinity Micro II System.

Hello all,
I was hoping to find someone familiar with the Infinity Micro II system. I was given one of these and just tried setting it up the other day. It's a bit odd in the fact that L/R out on the receiver goes to the sub and then the sub has L/R outs to go to the satellites.

I'm getting sound out of the satellites, but nothing from the sub. So that tells me it's not a bad physical connection. I'm wondering if maybe there is a bad crossover in the sub??

Setting my receiver to 2.0 format doesn't seem to have any effect either.

I'm hoping that someone here might give me a direction to start my trouble shooting.