My friend and I have come across a large stock of working ZX-81
computers that are missing keyboards. And a stock of others with bad
keyboards.
These are a lot from a former Sinclair Repair Center.
We'd like to get these working 100% again for sale along with the
remainder of the ZX-81 kits from Zebra Systems.
BTW... Stewart only has a couple hundred left, and when they're gone...
that's it!
Does anyone know of a source for these keyboards, or know of a company
that could make them up?
I have some samples and a schematic of the matrix so this shouldn't be
impossible.
We also have a cache of spare parts (Z-80's, ULA's, RAM chips, etc...)
for these units.
Also, we have a large collection of vintage New Old Stock TTL parts. We
are inventorying what we have now, and will post a website with part
numbers and quantities available.
They've been well stored, and seem to be in great shape.
We also found a small stock of Relays, and other parts. Those will be
listed on the site as well.
It's fun playing with a ZX-81 again. I dug out my TS-1000 and found it
didn't work anymore. When we opened it, we found that the Z80 had a bent
pin. And over the years it stopped making contact with the contact in
the socket due to movement of the parts and corrosion.
Once we bent the pin straight and reinserted the Z80, it came up like a
champ!
And... We also got my Coco III fixed. It came up with a pink screen. We
desoldered the 68B09 and put a socket in it's place. I stole a 6809E
>from a Coco 2 and popped it in. Voila!
It now works!
Computers in the old days were a lot more fun!
Al
Phila, PA
> To get back on topic about babbage's drawings,
> from what I read it was mechnical design that
> could not be produced with 18th century mechanical
> enginering.
That's often been conjectured, but, as usual, reality is somewhat
more complicated. Most other craftsmen probably couldn't have
produced what he designed. Along the way, he invented new
techniques of fabrication and management as well as computation.
However, he probably could have built it. He did build a small
version that operated as he intended. And part of the reason for
the construction project at the Science Museum was to determine
if the materials and tools of the time could have built the machine.
In the end, much of the reason he never built a full version of his
designs was that he was too much the stereotypical engineer.
Almost nobody except Ada could get along with him and he made
a number of enemies among those who would fund his work.
The money situation led to a dispute with his primary craftsman
who walked out with all the custom tools they had made. Then
as he was considering his options, he realized that he could
improve his design many fold and so dropped his efforts on the
difference engine in favor of the analytical engine. Even with that
machine, he kept stopping his efforts to realize it because he
was sure that he could build his new design faster than he could
finish the work he had started on the previous version. As I recall,
there were over 40 different designs for the analytical engine by
the time it was done, and he had never built a full version of any
of them. After his death, his son did assemble a small version
of one of the designs for the mill including some parts that
Babbage had already fabricated before his death.
There's no question Babbage was ahead of his time in many
ways. But he was also understood the materials and tools
well enough to design a machine that he felt confident he
could actually build.
BLS
>Date: Wed, 3 Jan 2007 16:00:41 -0600
>From: Mark Tapley <mtapley at swri.edu>
> Last OS *my* 68000 Mac Plus has run is MacOS 7.1. MacTracker
>claims 7.5.5, I can't dispute that as I haven't tried it but I expect
>it might not do much good (no RAM left for applications). Same is
>claimed for the Mac SE and Classic and PowerBook 100. MacTracker
>doesn't report the Outbounds (Jeff?) but since (I think) they used
>motherboards from the above systems,
The Outbounds used motherboards designed and built by Outbound but
with Apple ROMs installed which were scavenged from Apple Macs.
I can't speak to the Notebook series but the Laptop (a much cooler
machine, IMHO) will not run past Mac OS 7.0.1. However, this is a
limitation in Outbound support.
In order to use the Outbound Laptop Model 125 one needed to run a
system installer application from Outbound after installing the stock
Apple System. The Outbound installer definitely puts some code on
EEPROMs living in the Outbound Laptop. It may also do some
modifications to the System file, but I'm not sure about the latter.
It also installs some custom Outbound inits (control panels and
extensions, now days), for things such as power management and the
trackbar control.
Outbound went under before or pretty simultaneous with Apple
releasing 7.1 so the Outbound installer was never modified to support
7.1.
The required modification could be very simple from a programmer's
point of view but I've never been willing to invest the time to
figure it out. I'd have to develop the skills to interpret 68000
machine code in the Mac OS environment and for the Mac Plus-ish
hardware and figure out what's going on and that seems like a
daunting task when there are so many hardware projects around.
Still, if there are any 68000 savvy programmers out there interested
in taking a hack at it, it would be cool to get the Outbound Laptop
past OS 7.0.1. The jump to 7.1 would be very nice.
Additionally, the Outbound Laptop is an interesting beast in that it
uses 2.5" IDE hard drives. This is the first Macintosh to use an
IDE device by many many years. I don't think any Apple Mac used
them until the Quadra 630 and its performa and LC cousins.
Anyway, the Laptop only supports up to an 80 MB drive. I suspect
that it just has parameters for four drives stored in the installer
(20, 40, 60 & 80) but I don't know for certain. It would also be
very nice to hack the thing to support larger hard drives.
Have you tried to find 80 *MB* hard drives these days? Of course you
have; this is the CC list. It's a pain. I had a line on a place
in Florida with fifty or so in stock for about $40 each but didn't
have the money at the time and now they're gone who knows where.
Sigh.
Anybody have the modified Macsbug application? The Outbound Laptop
required a patched version of Macsbug.
Also, the Outbound Laptop was meant to dock with it's host computer
(the desktop from which the ROMs were taken). There was a card that
installed in the host and provided teh connection to the Outbound.
I've never managed to find one of these cards. I envision Pluses
and SEs going to scrap or being sold without the owners ever
realizing this very rare card is installed. Scrap is especially
likely because a Mac with the docking card installed won't boot up
unless the Laptop is docked (ROMs required). So the host machine
would appear "broken".
Jeff Walther
Jeff Walther wrote:
Additionally, the Outbound Laptop is an interesting beast in that it
uses 2.5" IDE hard drives. This is the first Macintosh to use an
IDE device by many many years. I don't think any Apple Mac used
them until the Quadra 630 and its performa and LC cousins.
Jeff Walther
---------------
I'm not familiar with the Outbound Laptop. What was the model number?
I do know that I was supporting Apple at Quantum in early 1994 and qualified
an IDE 2.5 inch drive for their laptops. It was one of the Blackbird
series, 160 if I remember correctly. Was made in Taiwan by Tatung as an
ODM. For a disk drive engineer, it was an unpleasant machine - the drive
was mounted above the CPU chip, dumping all the heat into the drive.
Quantum could never get it to meet Apple's temperature requirements with
this handicap. When Apple pushed hard, Quantum canceled the program and got
out of the 2.5 inch business - no way could they be profitable with those
temperature specs and Apple's pricing structure.
Billy
Dave Dunfield wrote:
The MOD8 was also known as the "GNC8" (Great Northern Computers),
and a later version used an 8080 processor (MOD80).
Any other MOD8/GNC8/MOD80 owners or interested parties out there?
Regards,
Dave
----------------------
I had completely forgotten about the MOD-8. I lived in Mississauga 1972-76
working at Control Data. We had an after hours club and the MOD-8 was just
coming out. So I know I have some of the documentation. The boards are
another matter. One member bought the complete unit and we reverse
engineered and made sets for our selves. So if I have anything left, it
would be knock offs. And I think I traded them before I left Canada.
Anyway, when I come across the documentation, I'll send it to Al and make it
available to the list.
I've got some 1702's around the house. How many do you need? Any
preference on colour? White ceramic or the later black with the foggy
window?
Billy
A friend and business associate recently asked me about how I dealt with
corrosion issues in vintage computer restorations. After I created this
writeup for for him, I realized it may also prove helpful to someone on this
list. Here 'tis:
Very bad corrosion from alkaline battery spillage:
-------------------------------------------------
Pour 30% Hydrochloric Acid directly on the affected area of the board. When
the foaming (along with "clouds" of vapor) stop, immediately rinse the board
in plenty of cold water. Follow with a rinsing of distilled water (to
eliminate any calcium in the tap waster). Dry in the open air or with mild
air pressure (I use the later to speed drying).
When originally told of this process, I was skeptical (even though sourced
>from a professional in the board repair business). When I first tried it, I
was amazed at the quantity of foaming (and clouds of vapor) from the acid
treatment. But amazingly, just as he said, the acid is not on the board long
enough to dissolve traces, components, etc. It works, just as he said it
would!
You can get 30% Hydrochloric Acid at most hardware stores. Its "common name"
is "Muriatic Acid". (Wear latex gloves when handing and protective eye guards
- and use outdoors or in a well ventilated area).
Medium corrosion (from any source):
----------------------------------
Apply "DeoxIT D100L" sparingly to the affected area. Wait 20 minutes. Repeat
if necessary. When the corrosion is completely removed, remove any excess
"D100L". Apply "DeoxIT G100L" (formerly known as "ProGold") sparingly for
long term protection.
Light corrosion (from any source):
---------------------------------
Apply "DeoxIT GL100L" sparingly.
Notes:
-----
"DeoxIT GL100L" - The military (and certain manufacturers) uses this "stuff"
on edge connectors in sensitive system connectors to maintain excellent
contact and easy removal/insertion w/o stressing boards and connectors. I've
used it for years on the edge connectors of vintage computers (PDP-8, PDP-11,
etc.) - and it is truly an amazing product. Works like perfection.
The "DeoxIT" products seem expensive - but because you use the stuff
"sparingly", a very small bottle lasts a long time.
Cheers,
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA
http://bickleywest.com
"Black holes are where God is dividing by zero"
OS install media is likely to be a big problem for any potential
restore, and likely documentation too
--
One of the folks involved with HLH lives in the Bay Area. I've
been bugging him to donate the Orion material he has to CHM.
Over the break I finally got around to writing a simulator for the Microsystems
International Limited MOD-8 (Modular-8). It has been very educational and
interesting, and the final result of being able to experience what is like to run
a very early microprocessor (8008) based system from Canada has been
well worth it.
The simulator is available on my site in the MOD8 section (Under "Designed
in Canada") - I have also included an 8008 assembler, and my retyped source
code to the MOD-8's ROM monitor (Monitor-8).
This is the first step in getting my MOD-8 system up and running.
I have a complete chassis (MOD8-8), as well as unpopulated ROM (MOD8-4)
and RAM (MOD8-5) cards.
What I don't currently have is the CPU (MOD8-1), Restart/TTY I/O (MOD8-2)
and Control Buffer (MOD8-3) cards. If anyone can help locate these cards,
it would be greatly appreciated.
I do have several vectorboards which match the MOD-8 card format, and I will
eventually construct the boards that I am unable to locate, however I would like
to restore the system to as nearly original as possible.
I will also need to locate a few more 1702 EPROMs - I have 3-4 of them, but
the system needs a minimum of 7 for the ROM monitor. Programming them
will also be a challenge (even my trusty DIO 29B doesn't do 1702s and the
requirement for -40v as logic-low makes for a more complex construction
project than I would like considering I will probably never need it again) -
but the MOD8 has a built in 1702 programmer - Currently, I am planning to
make a ROM board with a 2716 on it once I have the rest of the system
completed, and use it to program 1702s for the original ROM board - an
interesting kind of hardware/software bootstrap.
The MOD8 was also known as the "GNC8" (Great Northern Computers),
and a later version used an 8080 processor (MOD80).
Any other MOD8/GNC8/MOD80 owners or interested parties out there?
-----
Other things posted to the site over the break:
- Updated my paper tape tools with PTE, a Paper Tape (reader)
Emulator - allows you to send the content of the paper tape images
over a serial or parallel interface as if from a physical reader.
- Updated the NST (North Star Transfer) utility in my Horizon package
to include a "Clean Head" function - easier than using N*DOS "RD"
command to sweep the head back and forth over a cleaning disk.
- Added disk images to the archive for:
NorthStar Advantage (thanks Joachim!)
Coleco Adam
Regards,
Dave
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
Has anyone extracted images of the Read Only Storage
for the IBM 5100/5100 desktop computers? I haven't
seen any mention of it anywhere, nor any simulators.
Has anyone worked on this? Seems like it should be doable
and worthwhile. Though, it might be necessary to build
hardware to read out the ROS contents -- I don't think the
5100 provides programmatic access to the PALM object code for
the 360 and S/3 emulators, just the BASIC and APL code.
Does that sound right?
Brian
Generally still OT, but on-topic regarding the maintainability of
modern devices, did anyone perchance read the "A New Spin on White
Goods" article in the December 15, Electronic Design?
My clothes washer and dryer are going on 17 years and work just fine.
I see no reason that I won'd get 20-25 years of service out of them.
But reading about technology in the pipeline makes me wish they'd
last forever.
Motors controlled by DSPs with 10 A/D converters on chip, GUI
displays, talk about inventorying the stuff in your refrigerator
(using RFID tags on the food) really makes me wonder where the heck
repair parts are going to come from when the new appliances are 20
years old.
BTW, when I looked at replacement ovens over the last few days, I
found that just about all of the new ones are loaded with features
that I'll never use, such as "Sabbath Mode" (no kidding).
It looks like a brave new world, folks.
Cheers,
Chuck
