mangelhaft

I have an assortment of TV and VCR tuners in my parts box. I am trying to design a "tuner box" that recieves standard TV and outputs it to audio and video. I know the principles of how these tuners work, but am unable to find any data, except for the manufactures, on-line. Does anybody know where I might be able to find data sheets on these? Thank you, Richard E. Miller SSgt, USAF, Ret.