Non Linear Systems has a special place in my checkered past. When I was
13, an old engineer/ham friend of mine gave me an ancient (even then it
was old!) NLS 3-digit DC DVM. I was absolutely in heaven. He said " Here
ya go, kid, her's a box o' rattlesnakes fer ya!"
For those who care.. this DVM used an auto-nulling resistance bridge
implemented mainly with 10-pole 40-throw stepping switches. The wiper
arms had a ratchet wheel run by a pawl connected to a hefty electromagnet.
The device had one stepper for each decade (and hence, digit) with
precision resistors soldered to the the switch banks.
Applying DC voltage to the imput unbalanced the bridge, and the switches
began operating until the bridge nulled out. One set of contacts on each
decade switch was connected to a bank of tiny 356-style flange-base lamps,
which were mounted in staggered rows in an aluminum holder. the holder was
slotted to carry 11 thin clear plexiglass or acrylic panels, about 1" by
1.5", upon which the digits were engraved. (one for a period) When the
required lamp was lit, it shone down thru a hole in the carrier for that
particular panel, illuminating it edge-on and making it stand out from the
other realtively dark panels in the stack. The last digit was a zero and
it was damned hard to see in a bright room.
It had two rack-mount chassis, the switching part and the thinner
display unit, connected by the obligatory multi-core cable and massive
winchester connector. The switch box was entirely lined with thick felt
inside, to try and reduce the racket. I, of course, ran the thing open
most of the time.
Any change in the input levels caused the entire system to start at
'000' and then work up to a null... the last bits of a reading would slow
and then it would stop with the result in the display window, and it did
sound like a mechanical snake.. rr-rrr-rrrrrr---r-r-tictic-tic...tic. It
was my first piece of 'real' test gear and I'm kinda sorry now that it's
gone. snif. snif. O well.
No thanks, I don't want to buy another. I live too far away for the
shipping to make sense.. ;}
Cheers
John
In a message dated 1/7/2001 9:16:38 PM US Eastern Standard Time,
eweidenh1(a)hotmail.com writes:
> I recently acquired an Atari 1040f from a friend. It came with the SC1224
> color monitor which, for some reason gives off a really awful high pitched
> sound. Does anyone have some idea why this might happen? It scares my cat.
> Thanks.
>
It's usually a good sign that the monitor is about to die. You should here
how an SC1224 sounds when the rear of the tube has been snapped off at the
guns due to bad packaging and careless postal shipping and you unsuspectingly
plug it in and power it up. Heeyyy, ya need some parts? ;-)
BG
To me, it really comes down to one major issue: Are you running an emualtor
as a computer geek who likes to mess with antique stuff or are you running
the emulator as a company whose software is dependent on this hardware, but
finds it is no longer cost effect or perhaps even no longer possible to keep
said hardware in operation... From the Ubergeek perspective, then yes, I'd
think you want the emulator to be weird like the real hardware, though it
could be good to have a less flaky version for those who are merely curious
and have never experienced the real hardware... On the other hand, if you're
depending on an emulator to flawlessly run your commercial apps, then you
don't want it to ever crash, since a crashed emulator is lost time, which is
lost money.. Note that this is only meant to paint a general picture...
Will J
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com
Geoff,
There is an overall diagram of the skins on page 1-12 of the PDP-8
Maintenance Manual.
There are 3 pages of dimensional diagrams to the nearest eighth of a inch
in Chapter 6, Installation Planning, of the PDP-8 user handbook.
I will snailmail a copy to you.
I doubt whether they are good enough to use for "manufacture" tho.
The two side panels on the power supply would be relatively straight
forward. They are rectangular, wood which could be covered with a woodgrain
laminate, and aluminium edging. Little hooks on the back ensure they are
held firmly to the classic PDP-8 chassis.
The plastic doors would be much harder to make IMHO. We always refered to
them as plexiglass doors. They are a single piece of transparent green
plastic, with an opaque plastic top, plastic edging at bottom and aluminium
strips at the front. I think it is all glued together. The plastic top has
multiple, long slots cut in it for airflow.
I have a desktop classic 8 (Sydney Aust, not much use!) and can take digital
pics and send if that would help?
If any of your readers wish, I can also offer a large wall poster of the
classic PDP-8 and its teletype that I made some years ago.
Cheers
Max
Max Burnet
B A C K
Burnet Antique Computer Knowhow Pty Ltd
Mail PO Box 847 Pennant Hills NSW 2120
Phone +61 2 9484 6772
Mobile 0412 124 006
Email mburnet(a)bigpond.net.au
Web www.terrigal.net.au/~acms/a102.htm
Indeed. But the trick is not how to make 'em look fake so that no one
will be confused. I'm quite certain that can be arranged with precious
little effort. The trick is getting either real skins (thereby
circumventing all issues) or mechanical drawings of same so that my
correspondent can refurb his Straight 8. Specifically;
"...Cradle and module covers for a Straight-8 OR mechanical blueprints
for same to convert formerly rack-mounted model to a desktop machine."
Can anyone help this fella out? So far, the best information received
is a partial from Max Burnet (Thanks again, Max!) from Down Under; can
anyone better his information?
-----Original Message-----
From: Douglas W. Jones <jones(a)cs.uiowa.edu>
To: aw288(a)osfn.org <aw288(a)osfn.org>; comp-hist(a)shrimp.osfn.org
<comp-hist(a)shrimp.osfn.org>
Cc: COMP-HIST(a)cca.org <COMP-HIST(a)cca.org>; aek(a)spies.com
<aek(a)spies.com>; bitsavers(a)spies.com <bitsavers(a)spies.com>;
bsupnik(a)us.inter.net <bsupnik(a)us.inter.net>; classiccmp(a)classiccmp.org
<classiccmp(a)classiccmp.org>; djg(a)drs-esg.com <djg(a)drs-esg.com>;
geoff(a)pkworks.com <geoff(a)pkworks.com>; jones(a)cs.uiowa.edu
<jones(a)cs.uiowa.edu>; mac(a)Wireless.Com <mac(a)Wireless.Com>;
mbg(a)WORLD.STD.COM <mbg(a)WORLD.STD.COM>; nabil(a)teleport.com
<nabil(a)teleport.com>; rcs-l(a)shrimp.osfn.org <rcs-l(a)shrimp.osfn.org>
Date: Sunday, January 07, 2001 1:44 PM
Subject: Re: Straight 8 Skins
>One way to make sure the replicas are obviously replicas is to do them
in
>the wrong color. Honeywell orange metalwork, for example, with blue
tinted
>plexiglass instead of the grey that DEC used. Or, as suggested, just
mark
>them somewhere.
>
> Doug Jones
> jones(a)cs.uiowa.edu
>
One way to make sure the replicas are obviously replicas is to do them in
the wrong color. Honeywell orange metalwork, for example, with blue tinted
plexiglass instead of the grey that DEC used. Or, as suggested, just mark
them somewhere.
Doug Jones
jones(a)cs.uiowa.edu
Not to worry William, my correspondent is an honorable man, and I know
that any reproduction work would be properly documented and marked. The
real trick is finding the proper information so that the repro work can
be done.
I am fascinated to hear of replica Audions. Given the amount of work to
make them, and make them well enough to fool people into spending big
bucks, the forger had to do one heckovalotta work. If you're gonna
steal from people because you're too lazy to work for a living, why make
it that hard on yourself? Do something easier and more lucrative, like
smuggling narcotic babyfood or something. <grin>
-----Original Message-----
From: William Donzelli <aw288(a)osfn.org>
To: comp-hist(a)shrimp.osfn.org <comp-hist(a)shrimp.osfn.org>
Cc: Geoffrey G. Rochat <geoff(a)pkworks.com>; comp-hist(a)shrimp.osfn.org
<comp-hist(a)shrimp.osfn.org>; COMP-HIST(a)cca.org <COMP-HIST(a)cca.org>;
rcs-l(a)shrimp.osfn.org <rcs-l(a)shrimp.osfn.org>; djg(a)drs-esg.com
<djg(a)drs-esg.com>; aek(a)spies.com <aek(a)spies.com>; bsupnik(a)us.inter.net
<bsupnik(a)us.inter.net>; mbg(a)world.std.com <mbg(a)world.std.com>;
bitsavers(a)spies.com <bitsavers(a)spies.com>; classiccmp(a)classiccmp.org
<classiccmp(a)classiccmp.org>; mac(a)Wireless.Com <mac(a)Wireless.Com>;
nabil(a)teleport.com <nabil(a)teleport.com>; jones(a)cs.uiowa.edu
<jones(a)cs.uiowa.edu>
Date: Sunday, January 07, 2001 12:32 PM
Subject: Re: Straight 8 Skins
>> The two side panels on the power supply would be relatively straight
>> forward. They are rectangular, wood which could be covered with a
woodgrain
>> laminate, and aluminium edging. Little hooks on the back ensure they
are
>> held firmly to the classic PDP-8 chassis.
>>
>> The plastic doors would be much harder to make IMHO. We always
refered to
>> them as plexiglass doors. They are a single piece of transparent
green
>> plastic, with an opaque plastic top, plastic edging at bottom and
aluminium
>> strips at the front. I think it is all glued together. The plastic
top has
>> multiple, long slots cut in it for airflow.
>
>Geoff, if your freind does fabricate new covers for the PDP-8, please
>tell him to mark it as a reproduction in a permanent, but un-obvious
way.
>For example, just a simple note like "REPLICA COVERS: 20 JUN 2001"
etched
>on each cover, inside, in the corner, in very small letters. This will
>prevent some jerk in the distant future trying to sell it as a
prototype,
>or just paint a clearer picture of the provenance of the machine long
>after it has changed hands a few times. Being an important machine
>(PDP-8), it will always be valued highly and may greatly outlive its
>current owner.
>
>Quite a few years ago, some guys started making replica Audions and
other
>very early tubes/valves. Some of them are marked, but many are not, and
>at least a few people I know have been burned.
>
>William Donzelli
>aw288(a)osfn.org
>
Ok all you ex-aerospace contractor types out there, here is a challenge for
you.
My new VAX came from an Aerospace contractor and had a Q-bus board in it
>from "K Systems Inc" (the parent company of Kaiser's gov't contractor
business. according to Hoovers.com)
The board is dual width Q-bus marked "K Systems" "AITG" "Rev C"
On board it has a Z80B, Z80BPIO, AM9513 (floating point?) MK6116 (2K RAM),
2764 EPROM marked 35112A0B (c) 1993 KSI, and a part marked MK4501N-12 (what
ever that is). Then it has a bunch of analog circuitry, four rotatable
switches (set to 0,0,0,0), 7 thinline coaxial connectors, an LED, a 20 pin
(10 x 2) connector, standard Q-bus decode logic with what looks like a
bunch of dip switches to set the CSR and what looks like a temperature
compenstated and potted crystal oscillator.
I'm guessing its some sort of time base generator. I'm sure 'sho dev' won't
know what the heck it is ! :-)
--Chuck
This is pretty cool, I have now got a BA212 based VAX for the House of VAX!
I just picked up a VAX 4000/200 in a BA212 chassis and it is the first one
I've ever seen outside of the MicroVAX "technical handbook"!
Fortunately it came with all the parts (only some minor disassembly that
was easily corrected). Unfortunately it did not come with the rack "drawer"
that mounts it into a 19" rack. This will have to be corrected. Hopefully
its presence will attract the necessary parts :-)
For those who don't know what it is, the DEC BA212 chassis is a "low
profile" rack mount chassis for a DEC Q-bus based VAX system. There is a
similar chassis called the BA213 which sits vertically consumes 27" of rack
real estate, and has drives in the top half and cards in the bottom half.
The BA212 leaves the drives in the "front" but _behind_ the drives is lays
a Q-bus backplane down horizontally "into" the rack taking up only 14" of
space. This is why you need the drawer sides because to get at the cards
you have to slide it way out of the rack!
Anyway, I've got the 4000/200 front bezel for it (the version of the
technical handbook I have doesn't mention the 4000/200 in this chassis
because I believe it was introduced later)
One of the neat features I discovered is that it has a couple of "feet" on
the front that props up the front of the chassis if you have it out of a
rack so that air can flow through it. Just really neat. I'll try to get
some pictures of it and put it up on my VAX pages.
--Chuck
Hi Gang--
Anybody want some rd-51's? They're the real
McCoys, blessed and badged by DEC. They even
come with sleds.
$1 plus shipping. I'll even test 'em to make
sure they work.
Jeff
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