Receiver (SCHT400) Stopped Outputting Subwoofer

My Panasonic SCHT400 stopped outputting the receiver. I tried the sub on the L channel and it works fine so it's not a wiring issue. I tried turning the subwoofer on and off via the receiver but no output. The sub is passive and just accepts speaker wire. Bad idea to hook up RCA to the Tape Out and then splicing the other end into +/- speaker wire for the speaker?

Manual -> http://service.us.panasonic.com/OPERMANPDF/SCHT400.PDF

I am going to try changing the Front speakers to "Large" and wiring the sub to one of the front speakers per this thread:

http://www.avsforum.com/t/1038948/hooking-up-subwoofer-to-receiver-with-speaker-cable#post_14075583

I set the subwoofer to OFF, set the Front speakers to "Large", and connected the subwoofer to the left speaker terminal and I have some subwoofer output. It's fairly low but it does give me some bass. I am fresh out of ideas.