Here's a useful tip: Roland/Boss provides manual downloads for most of their products. You enter your email address and they will send you a download link to a pdf file with the manual.
All manuals contain a copyright notice stating that reproduction is not allowed without written permission from Boss. We may want to contact Roland/Boss and ask permission before we start scanning.
fyi, some manuals of current Boss products are also available as 'straight' downloads from bosscorp.co.jp (i.e. *without* having to receive a link via e-mail):
I didn't check them all, but they have manuals for the DD-6, PS-5 (44 pages!), TU-2, and SYB-5 but not the CE-5, DD-3, RV-5, or SD-1. and they're all in English as well....
wait, here's a listing of all owner's manuals available from bosscorp.co.jp: