3 Jul
2000
3 Jul
'00
1:48 p.m.
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, July 04, 2000 3:40 AM
Subject: Re: HP 85 stuff
> > 2) Any
software about?
>
> Yes. lots but none is posted on the web that I know of. Beware
that the
> HP cassettes are very prone to broken belts and
shedding their media
so
> original tapes may not be usable.
Ok, I'll keep that in mind. I'm going to try and track down some NOS,
bound to be a fair bit floating around.
HP85s with an HPIB interface and a mass storage ROM
(IIRC) can support
floppy drives. If you have this sort of set-up, it's worth copying any
tapes you find onto floppies.
No, I don't have any of the addons for the machine, I'll be looking for
them now that I know what to look for.
> >First HP I've been able to find, nice
little machine....
>
> Yes, they are but they have two problems. The "rubber" feed
wheel on
> the tape drive turns to goo
I'm going to pull the thing down and check that. Copyed a prev msg about
a replacement. Whatever works.
> and the two belts that operate the printer wear
> out. You can test the printer by pressing the "TEST" button. It
should
> display and print the full character set.
Printer seems ok.
I've only ever once had an electronic fault on
one. This was a shorted
capacitor on the PSU/printer driver board (the vertical one to the
left
of the printer assembly), and it caused at least one
of the PSU
outputs
to be missing.
Ok, I'll keep it in mind if it ever plays up.
This board can be run disconnected from the rest of
the machine (just
connect the input from the mains transformer). Also, the custom 40 pin
printer control chip is socketed on most machines, and can be removed
and
stored in conductive foam. This lets you work on the
PSU with little
risk
to anything you can't replace if you make a
mistake.
sounds good.
FWIW, much of the logic in the HP85 runs at 6V (not a typo).
Unusual.
custom interface IC that links to the processor bus
and lets you hang
a
conventional 5V microcontroller-based interface off
the other side.
Information on this seems to be hard to find, although the HP-IL
interface user manual includes a schematic of that interface, with
pinouts of the bus and the bus translator chip.
Hmmm, that has possibilities.. I am also lead to believe the 85 can
talk to various pieces of HP test equipment, and that they share a
common bus. (With the right interface of course).
Oh, one last thing. If you want to take the top off,
first pull off
the
eject button from the tape drive. Then undo the screws
on the bottom,
and
lift the casing off. If you don't remove the eject
button first,
you'll
have problems getting the case to come free.
Ok, thanks for that. Often the worst part of fixing (ptbl tv for
instance) is not the fault, but getting the case either on, off or both.
With some stuff it's like getting an egg back into it's shell.
cheers
Geoff Roberts
Computer Systems Manager
Saint Mark's College
Port Pirie,
South Australia
geoffrob(a)stmarks.pp.catholic.edu.au
netcafe(a)tell.net.au
ICQ: 1970476