Check the dumb things first... your Yamaha receiver... when you hooked up the digital coaxial to the different coaxial inputs on your receiver...
(far left in this image... they may not be in the same place on your AVR - this is a Yamaha RX-Z9) did you go into the INPUT menu on the receiver and reassign the input you used each time to the source you were using? ie: if you had it plugged into the DVD coaxial in, did you make sure in the input menu on the AVR that "3" (the number under the DVD Coaxial Digital input) was assigned to "DVD" or "DTV" or whatever SOURCE you're using.
Failing that if you have a multimeter and want to simply test if you're getting a signal out of the digital out on the TV... put the negative lead to the shield, the positive lead to the pin and look for a 1VDC peak to peak signal.
If you have nothing, look through the tuner manual to see if the digital out needs to be enabled.
Bren R.
