Join Date: May 2002
Location: Toronto, Rogers, 9865 & 8300-eHDD, Sharp LC75N8000U, Denon AVR4310Ci; Sony KDL40W3000, 9865
Does the Onkyo allow you to upconvert the incoming analogue signals to say 1080i/P? If it does, then that may solve your problem, if the TV doesn't accept 480i via HDMI.
You could check if that's the case by connecting an HDMI device directly to the TV (DVD player, STB, etc) and try setting it to output 480i via HDMI - you should get an error or a blank screen, then don't change it to 480i, otherwise your device may need to be connected differently to change output format - depends on how the output format is changed on the device - a button or menu...