Have you actually looked for the repair manual for that printer online?
I found the one for my Epson R200 without much problems.
All parts are listed...

Yes. Nothing turned up.

If someone knows where to find the manual for HP Photosmart 3110/3210/3310
all-in-one printers (not the LaserJet 3210 -- why a company would duplicate
model numbers...?) please let me know.

Thanks for your reply.