This may help some as it did for me. I have a well-out-of-warranty Onkyo TX-NR809 that just lost all audio. I started looking into replacing it and came across this warranty extension deal that Onkyo, to their credit, was offering to owners who had the issues involved. I'm not sure as to which models it applies, but simple entry of the Serial Number at this link https://care.onkyousa.com/na/003_...ountry=USA
will reveal if it is covered. After choosing "new" (vs. Refurb), you enter your serial no. and check off the issue involved (mine was loss of all audio). The site will then confirm whether or not it qualifies.
If it does, they will give you the choice of: (1) free repair (shipping included) - (Note: they warn if there are other issues involved, there may be a charge); (2) a rebate offer (mine was $225) if you purchase certain specific Onkyo models; or (3) a direct trade-in for discounted specific models they offered (they offered me the TX-RZ810 for $349 + tax and I jumped on it - 2 other more expensive RZ line models were also offered). I'm not sure if the offers will differ if you have a different model. I tried an old TX-NR606 I had and it did not qualify.
The trade-in deal only requires that you buy the unit at the discounted price (promo code and link is emailed if you choose the trade-in option) and send them the serial number sticker from the old unit within 10 days of receipt of the replacement. The rebate is a bit more onerous (you need to send the purchase receipt from an authorized dealer of the qualified model and various serial number stickers from unit and box). The deal seems to end in July 2018, though repairs might still be able to be available through December 2018.
I'm not an experienced poster, but searched to see if this was posted previously with negative results. I did see something similar for a Pioneer unit that appeared helpful though.