New member introduction, questions on HP 21XX series machines, reliability and maintainability

From: William Maddox <wmaddox_at_pacbell.net>
Date: Wed Oct 29 19:25:11 2003

Hi, all.

I just joined the list. I've had a long-time
interest in old computers, and rescued a "straight-8"
many years ago when I didn't think anyone else
thought of it as anything more than junk. It was at
least minimally operable when I obtained it, but I
went off to graduate school before I could find any
software for it, and it's been in storage at my
father's office in Florida for ~15 years now. I hope
to move it to my current location in the next few
months after a family visit, but in the meantime,
I'm looking to acquire another minicomputer from
the core memory era, hopefully something slightly
more compactly packaged than the (presently rackless)
rack-mount "8".

After some research, I have settled on the HP21xx
line as a good candidate. These seem to be very nice,
well-built machines with a reasonable architecture,
a good paper-tape BASIC, and a full complement of
"blinkenlights". It seems that these machines are
actually still used, however, and I've been quoted
some pretty steep prices from a nearby dealer in
in used HP gear.

I'd be interested in comments and advice for a
prospective 21xx owner from those on the list who own
these machines or have used them. I'm particularly
concerned about reliability, since at the price I
expect to pay, I want to keep it operating for a long
time to come. How difficult and expensive are they to

troubleshoot and keep working (say, compared to DEC
PDP-8)? How available are contemporary replacements
and/or new old stock for the ICs? Are there any
proprietary components that are particularly prone to
failure or hard to replace that I absolutely must
obtain up-front as spares? What about the core stacks
themselves? The dealer that I talked to seemed to
think these were problematic (though I did not speak
with his technicians), while my instinct would be that
the core itself (not the driver electronics) would be
among the most reliable and stable components, barring
visible corrosion damage.

Also, any suggestions on places to look for these
machines on the cheap would be welcomed. What I'm
most looking for is a 2115, but would likely be
interested in the somewhat later 2100 as well.

Thanks,

Bill
Received on Wed Oct 29 2003 - 19:25:11 GMT