Same problem I had. Check out the input allocation on that patch. Tuner only works on input 1 - so if you have, say, a Variax connected but "inputs" are specified as Input 1= Guitar, Input 2=Variax, then - even if only the Variax is actually connected it won't show up or register in the tuner. It's totally frustrating if you regularly use both a guitar and a Variax with the HD500. Crazy arrangement!
Correct. It is the way it is designed. The TUNER only works for whatever is connected to INPUT 1. I have never understood why it is like that and I have just worked around the limitation when I have encountered it. Why can't the tuner also be used for INPUT 2? Maybe there is some good technical reason why but I have not seen anything reported to explain it. Perhaps it has already been mentioned on Ideascale and if not, perhaps it should be suggested.