Onkyo Receiver dead channel

I have an older Onkyo receiver, model TX 844. There is no audio output from the right channel, for either set of speaker terminals or for the headphone jack. I have located only one fuse, on a board directly behind the front panel power switch. Are there any other fuses that should be checked, or any other known or obvious issues with this I should look into? Or is this now a tree lawn item? Thank you!