HP 2100A stuff - info needed

From: Frank McConnell <fmc_at_reanimators.org>
Date: Wed Sep 24 10:15:40 1997

Tony Duell <ard_at_odin.phy.bris.ac.uk> wrote:
> On Tue, 23 Sep 1997, William Donzelli wrote:
> > > > > 2895B Tape Punch #1632A03303 FACIT model 4070
> > > >
> > > > Yep, this is a badge-engineered Facit paper-tape punch.
> >
> > Mine came with some sort of rack mount kit that I have not been able to
> > comprehend yet. I think I am missing parts.
> There is a rackmount kit shown in the Facit 4070 service manual/parts
> catalogue (which I have). I can look up how that one goes together and
> post details.
> >From memory it consists of a frame that fits round the 4070 chassis (the
> 4070 sits with the reels on the right, and the reels themselves vertical.
> There are little friction pads at the bottom to prevent it sliding out,
> and clamp screws that go in from the top to hold it in place. The whole
> frame mounts in the rack in the usual way.

I have one of the HP rack mounts in my living room right now (on its way
to storage with the punch). Unfortunately I can't post pictures for
y'all but here is how it goes.

Basically it is a sliding shelf with a front, with a hole in the front
for the chad box to poke through. There's a little metal plate
screwed to the shelf near the front, as well as a couple of black plastic
circles toward the rear. Those are just guides to keep the punch
from wiggling around too much as it punches.

There are also a couple of dividers screwed down and held apart
with standoffs toward the left of the shelf. At a guess these make a
handy place to store a few reels of paper tape for when you have to
refill the punch.

Finally there are screw-downs for a twisted pair of wires that go up
to a power light mounted in the front of the rack. Well, it's supposed
to be there, the lightbulb is missing on mine; I think it got mashed in

The shelf needs to slide so you can get tape off the takeup reel (if
you don't just let it spill out the front), get at the punch's
controls and most of the tape path, and feed the punch. Oh, also note
that there is a little widget at center rear between the shelf and the
frame; this is to keep the shelf from sliding out due to vibration
from the punch.

> I _believe_ there's a special (metal?) chad box and front lid on rackmount
> 4070's. Oh, and the writing on the control panel is turned through 90
> degrees so that it's readable when the unit is in the rack. All my 4070's
> are table-top models.

It isn't clear to me that my 2895 punch is any different from a table-top
unit. Smoked-plastic chad box, BTW.

> > My sense (i.e. ears) tell me that the power supply is a switching type,
> > probably one of the first for computers, an is probably a bear to fix. Of
> > course, all of the house numbered HP parts does not help either.
> Switching PSUs don't bother me. The HP seems to have a large 50/60Hz
> transformer, so the chopper is (I guess) on the low voltage side anyway
> (like on most PDP11s). That sort of supply is not that hard to fix _given
> schematics_. Heck, if I can get a Boschert 2-stage running again, I can
> handle just about anything :-)

OK OK OK. I am planning on pulling all my 2100 manuals out for y'all.
I can't do it just yet, though; there are other things ahead in the
queue. Maybe this weekend if I can get some other pieces into place.
Fair warning: I am a software kind of guy; I know what a schematic
looks like but you shouldn't count on much more. OTOH, I can work
a photocopier.

If y'all are interested in a little story about the 2100 power supply,
I suggest getting Analytical Engine 2.3 from CHAC's web/ftp site and
reading the interview with Barney Oliver. One spoiler: yes, it is a
switching power supply, and there was something patentable in its

-Frank McConnell
Received on Wed Sep 24 1997 - 10:15:40 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:30:38 BST