Having purchased a 1994 Kenwood music system from a Charity shop in 2013 (it was a high end product in its day), I found myself not quite knowing where to plug in what, and how to do this, that and the next thing. I needed a Manual, and after failure with another online 'Manual provider' I found Owner Manuals dot com. Well, I wasn't sure, but it was only $5, and if things didn't work out, I wouldn't have lost much...
But things DID work out. After paying my childrens inheritance money, $4.99, I was sent a Manual for my Kenwood System very quickly. Alas, it was in German, and being Scottish, I could not read it or get my system in order from it...a rapid email to them brought the English Manual in short order, and my retro-system was and IS up and running in it's regulation settings.
I am very grateful to http://www.owner-manuals.com for their quick service and for even having such an obsolete Manual in the first place! If you need a Manual for ANYTHING, try here first. I wouldn't be surprised if I bought a 1928 Marconi radio, and got the user Manual for THAT here too!