In our previous post on the 4th R, we listed a few sites that were good sources of instructions on how to repair things in your home; Now, courtesy of the Red Ferret, we have a few sources for user manuals, so you can operated them. I will search for information on my HP 3330 combo printer.
The User Manual and Guide site has thousands of manuals in every language, all scanned and available in PDF form. It certainly is not complete and does not cover all manufacturers, but if your product is from any of the companies it covers, you are in luck. Ugly and old interface. Sorry, no Hewlett-Packard.
Safemanuals is another site that has thousands of manuals in dozens of languages. More sophisticated interface and it includes HP, but sorry, no 3330.
Retrevo is a real find of a website. It not only found the manual instantly, but has price comparisons, user reviews, ratings and more. Lots of useful stuff but for electronics only.
User-manuals has thousands of pdfs of manuals, but it is expensive- they charge what appears to be a minimum of nine bucks a hit. However they are serious- I found the manual for my 1972 Sherwood amplifier.
So if you find it in the attic or at the dump, there are lots of resources to show you how to turn it on and fix it. Next: Where to find things.