Hey all --
Picked up an HP Integral PC. Probably paid too much for it but
something about a luggable HP machine with a plasma display running
HP-UX from ROM seemed irresistible. But I digress.
It's certainly aa beautiful machine. Is it a plasma display, though? I
thought I read it was an electroluminescent panel (basically exicitng a
solid phosphor maaterial in an alternating electric field). I must admit
that the display is the one part of the machine that I know ittle about,
I did dismantle the display module in one of my 2 Integrals, there's a
PCB on whcih most of the ICs are custom and unidentifiable, so I didn't
go much further. The display, of course, was not made by HP.
Has anyone archived the manuals for this thing? I've been unable to
The beast place to look for manuals for old HP machines other than
handhelds is http://www.hpmuseum.net/
. I think at least the (l)user
manual is there. But be warned that 'my' scheamtic there is an early
version, and I know I made an error in the address decoder circuit
(basically I miscounted the address pins on the CPU at one point). The
HPCC CD-ROM contains an updated version.
I ahve never seen an HP techical manual for this machine, but would like
to. Low level programming info would certainly be interesting.
find anything in my searches on the internet. Found
archives (and after lubricating the floppy mechanism I've been able to
Actually, most of the time the dive is suffereing from hardened grease.
It doesn't need lubricating, it needs taking apart and cleaning. I wrote
an artice about this (in general, not Integral-specific) in the HPCC
journal last year, I susepct you can purchase a copy of the appropriate
issue from HPCC.
Anyway you must have been inside the machine. How far did you get? The
order I dismantle the machine in is :
Remove the ROM cover and take out the HP-UX ROM.
Remove expanison cards, then 2 screws and the back cover
Remvoe the rear screening plate (6 screws and a little plastic peg thing)
Remove the floppy drive (unplug the 2 cables, then 3 screws and slide it
out. Don't lose the eject button and spring.
Undo the screws and free the logic assembly, Reach under it and unplug
the cable from the display. Unplug the cables from the lower edge of the
PCBs going to the fan and PSU/expansion box. Remove the 4 screws holding
the front screen ot the logic module and unplug the THinkjet cabling.
Then the whole logic unit comes out.
Separate the logic boards from the chasiss plate.
Rmwove the PSU/expansion box -- take off the earthing nut on the
expansion backplane, then the 4 screws at the rear sides and slide it out
Take of the nuts and screws and take the cover off the PSU/expansion box.
I find it easiest to lift the cover up as far as it will go, then unbolt
the HPIB conenctr from the back and take the cover off with the HPIB
Remove the Thinkjet controls. First remove the logic assembly mounting
spacer to free the earthing tab. Then one screw and take the control out.
Take out the printer mechanism. It's just a few screws.
I normally don't need to remove tbe display.
Anyway, the circuitry is a mix of standard and HP custom parts. The only
chip I've not seen used elsewhere is the display controller. Other HP
ASICs includ the HP-HIP interface chip, the Thinkjet controller, its RAM
and ROM, and the HPIL chip that interfaces that to the rest of the machine.
The keyboard connector is HP-HIL. There are 2 connectors, but they form
part of the same HP-HIL chain, so you're limited to a total of 8 (or is
it 7) devices. There's some circuity on the logic board to complete the
chain if you honly have one connector in use (as is often the case, you
just have the keyboard). It doesn't matter which connector you plug the
The Thinkjet printer is conventional-ish. It uses the normal Thinkjet
procrssor, Font ROM and RAM (which communciate with the processor using a
Saturn bus (!)). The Thinkjet processor has a built-in HPIL interface,
hence the 1L3 HPIL chip next to in o the board. YEs, there's a tiny HPIL
loop to link the printer to the rest of the machine.
The printer mechanism is standard but for the fact hat the cables are a
lot longer than those in a normal Thinkjet. This is a particular problem
wit hthe carriage flexiprint, which is thus not the same as the one in
any other Thinkjet. And as is well-known,Thinkjet ink is corrosive. Never
leave a cartridge in an Integral. I think if I ever need to replve the
flexiprint in my Integrals, I'd use anormal-length one and kludge up some
kind of extension.
Do you ahve any expansion boards? The most useful ones are a memory
expanison (1M is the largerst HP one I've seen, I posted an article here
a couple of months back about expanding the 512K one to 1M), and an RS232
board (in fact I bought a second Integral fairly recently mainly to get
that board). I also have an internal 300/1200 baud modem and a ROM/EPROM
drawer for mine, but not enough slots :-)
make use of it...) but not much documentation. Docs
for the HP BASIC
for this machine would be nice, too.
I've only played with it for a little while, but it seems like a really
neat machine. (Though it seems like this thing is just begging for some
sort of mass-storage other than the internal floppy and RAM. Anyone
have an HPIB hard disk for sale? :)
The maion prolems with this machine are, IMHO :
Not enough memory, you really need a 512K or 1M card
No serial port -- the RS232 board is something you want to find.
And therefore not enough slots, if you add memory and RS232, you have no
slots left. There was an expansion box, but I've not found one yet.
No hard disk. Yes, you can add an external HPIB hard disk, but that
rather defeats the point on a portable machine.