I bought an Onkyo AV package some years ago from Best Buy. The receiver I got with it was a TX-NR509 and now it has developed the no sound fault.
The good news is that Onkyo know they have a problem with many of their models and now offer a free repair for those with problems. You must enter your product serial number to check your device is covered but I hope this is of some help to others.
I looked for some time before stumbling on this information.
The repair link link isuk.onkyo.com/en/…tml