Originally Posted by Super_Chicken
Cable box is Scientific Atlantic Explorer 4250. It only has Composite, Component, and DVI out for video. Composite and Optical for audio. No HDMI.
Wega has both 2 Component, 1 DVI, no HDMI.
Originally it was cable box Component to component on TV, Cable box's composite Red/White to receiver for sound. Now it's cable box's Component and Optical to receiver, receiver's Hdmi to tv's dvi picture. DVI on the box was never used. I tried it once and it didn't work but I think I was using the wrong DVI cable.
Except that from what you also say I believe you've now gone back to all-component video, from box to receiver and then on to TV. Right?
Talking solely about video here, I'm not sure I can imagine what "the wrong DVI cable" could have been. If the box has DVI out and the TV has DVI in, what other than a pure DVI-to-DVI cable could have been used?
Anyway, if you previously had a fine/better picture previously using all-component video from box to TV (according to your father's subjective observations) I'd certainly say that there's no reason to change anything now just because you have a new receiver to support source switching and multi-channel audio.
Unless you're going to go all-DVI (using a DVI-to-HDMI cable from the box to 863, since the 863 doesn't have DVI) and then HDMI-to-DVI cable from the 863 to the TV, I don't see any purpose to involving a conversion in the 863 from component video in (from the box) to HDMI-to-DVI out (to the TV from the 863).
Although I'd probably want to see by actual comparison if there was any difference or degradation from the two different approaches. Since your TV supports it, and since the 863 can easily be changed (with "manual setup") to handle either type of input, with the availability of a few additional cables (not necessarily cheap, but if you have them you can use them) you could try it out for yourself.
Connect the box to the 863 using BOTH (a) component video and (b) DVI-to-HDMI. And connect the 863 to the TV using BOTH (a) component video and (b) HDMI-to-DVI.
Now you can use "manual setup" on the 863 to switch between the two inputs, which are going to automatically be fed out through both component video and HDMI (i.e. to DVI, to your TV).
Also, you can use the TV to switch between the two inputs coming from the 863... either component video or DVI.
And pick a good stationary image source (some scene that has good edges, color, brightness, contrast, etc., but is also quite still, like something from the Leno show or NBC news) and switch things back and forth for comparison with your own eyes (and your father's).
Personally, my intuition would lead me to guess that the DVI-based path between box and TV through the 863 would be possibly slightly superior than the all-component video path. But it might not be noticeable, nor might it be worth the cost of new cables. However I believe DVI is the only way you can get "dot-by-dot" (i.e. zero overscan) from the set (if available), if that's important to your viewing.
Anyway, if your now in-place all component video arrangement is now satisfactory that's really what matters. But it would just take two of the right DVI-to-HDMI cables to really perform the scientific experiment.