Get the service manuals, etc. off of the DVD produced
by "The Museum of HP
Calculators":
http://www.hpmuseum.org/
I don;t normally like electronic documentation (much prefering it on
paper...) but that set of CD-ROMs (I don't have a DVD-ROM drive, so I
bougth the 10 CD set) wsa well worth the money. It's about what you'd pay
for a couple of manuals at some places... If you like HP calculators and
small computers, you need these disks.
For larger HP machines, and peripherals (including printers and plotters)
there's a lot of free scanned manuals (pdf format) on
http://www.hpmuseum.net. Of course many of the service manuals are
boardswapper guides, but I find it quite amusing to read those and then
work out how to do the job properly :-)
-tony