Optical Audio Problems with Pioneer VSX-816

After two years of owning it, my Pioneer VSX-816 has developed a problem with the center channel cutting out intermittently. Sometimes I can crank the volume up to a LOUD level (briefly and then turn back down) and the problem is fixed. If not, turning the receiver power on and off usually fixes it. Sometimes I have to unplug the RCA cables from the back of the receiver or jiggle them and that fixes it - sometimes.

So, I gave up and bought a digital optical cable from Monosource and connected it from my Dish DVR and saw a nice little red light coming out of the other end of the cable. Then I connected it to the TV/Sat Optical In port on the back of the receiver.

I made sure I selected TV/Sat. I got a great picture, but no audio! I switched the audio selection on the Pioneer VSX-816 to Digital, then Auto, then Analog, and still no sound.

I have two cables, so I tried them both. Still nothing. I even tried hooking up my dvd player with the same cable - switching the input to TV/Sat...and no sound.

Please help me before I jump off the roof - or better, throw my Pioneer VSX-816 off!

OK, please please, anyone?

OK, I've solved one problem with the VSX-816 by getting the optical input assigned to the correct input (thanks Chris Wiggles!).

But I still have the problem with the center channel cutting out intermittently. Sometimes I can crank the volume up to a LOUD level (briefly and then turn back down) and the problem is fixed. If not, turning the receiver power on and off usually fixes it. Sometimes I have to unplug the RCA cables from the back of the receiver or jiggle them and that fixes it - sometimes.

If there is a short (?), how can I fix this? I'm really regretting buying a Pioneer!