John,

I had a very similar situation as you...D* HD tivo using one of the 990's dvi inputs and a toshiba hd-a1 using the other. Purchased a PS3, and needed another input. I purchased the exact manual switch Gonk links to, and it has worked out great for me. I don't see any video effects on the picture using the switch...but have not actually put up test patterns to compare with/without.