The manual for the OP-80 paper tape reader is available for download on the
internet at no cost, and has been for some time (years), from multiple
sources. It's on Howard's site, however, which may be the quickest and
easiest way to get it. These are surprisingly valuable, on a few occasions
they have gone for over $100 on E-Bay, although $40-$70 is probably more
common (that's for the reader itself, of course, not simply the manual).