It has been about 20 years since I was involved with the AMI chip, but I do
recall that the AMI version is a superset of the MOT version. It has
features not present in the MOT part. I rather doubt they are
interchangeable without firmware modifications.
AMI also made a few parts for the MOT processor family which MOT themselves
never got around to building. One example is the 6834, which is a
two-ported RAM, I believe. It was intended for communication between
multiple processors in a system, but MOT really didn't implement this until
they put out the 68121, which was apparently intended as an intelligent
peripheral controller for an MC68000 family processor. The '121 was a 6803
with a built-in 6834. The part's use was envisioned in a rather narrow way
and, hence never saw much popularity, as it was difficult to use in any way
outside this narrow scope.
I'll see if I can find an old AMI databook . . .
Dick
----------
> From: Arlen Michaels <amichael(a)nortelnetworks.com>
> To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
> Subject: RE: here's the list . . .
> Date: Wednesday, February 24, 1999 12:02 PM
>
> On Mon, 22 Feb 1999, Roger Merchberger <zmerch(a)30below.com> wrote:
>
> > >> BIOTECH ELECTRONICS BCT800 graphics board - uses AMI 68047 chip and
12
> >
> > Erm, sounds like that AMI chip is a clone of Motorola's 6847 VDG, which
> > was
> > used in Tandy's CoCo 1 & 2, and the MC-10.
> >
> > I wonder:
> >
> > 1) if they're pin compatible,
> > 2) if they've got added functionality -- might be fun to play with in
one
> > of my CoCo's if there is!
> >
> It's quite likely that AMI's 68047 is a clone of Motorola's 6847, because
> AMI used to supply pin-for-pin equivalents of a number of Motorola
> 6800-family devices, including the 6821 Peripheral Interface Adapter and
the
> 6850 Asynchronous Communications Interface Adapter. The 68047 and 6847
are
> both 40-pin chips, but I don't have an AMI datasheet handy.
>
> Arlen
>
> --
> Arlen Michaels amichael(a)nortelnetworks.com
Kevin's message propelled me to look through our library catalog for all the
DEC handbooks we have. (I already sent the list to him.) That made me think
of a question I've had for a while. Megan or Allison, maybe you know the
answer? You two seem to have vast collections of manuals.
Our library has volume 1 of a two-volume _Introduction to Programming_ set.
I've always wondered what was in the other volume. (It covers details of
the languages supported on the PDP-8.) But I've never seen the two-volume
set anywhere else, just a one-volume book.
And while I'm at it... We have the OS/8 handbook as well. I've never been
clear on what the different versions of OS/8 are, so I don't know how early
or late our handbook is.
The OS/8 book does mention using a TD8E system, which requires either 12K of
RAM or a special ROM page. Unfortunately, the Intro to Programming handbook
doesn't explain how the ROM is installed. The programming handbook is
specific to the 8/E, but it omits a lot of details about customizing your
8/E.
I do understand that the TD8E was a total corner-cutting move -- it shifted
the burden of getting the bits off the tape from the hardware to the
software, right? -- and is universally regarded as a disgrace.
-- Derek
I am trying to compile a pictoral history of DEC handbooks. The tentative
title is a Handbook of DEC Handbooks. Trying to find a definitive list of
all such publications is proving to be very difficult. The Compaq-version of
DEC is still very much unorganized. The Smithsonian is doing their best, as
is Charles Babbage Institute, and TCM is next on the contact list, but
please consider helping. I believe the list can only be compiled through
grass-roots channels.
If you have any DEC handbooks, please send an email directly to me with the
titles and dates of publication. Please only send a message if you have the
title, not just if you sort'a know it might exist.
I'll publish the list on my web site.
Thank you all.
----------------------------------------------------------------------------
-------------------------------
Kevin Stumpf * Unusual systems * www.unusual.on.ca
+1.519.744.2900 * EST/EDT GMT - 5
Collector - Commercial Mainframes & Minicomputers from
the 50s, 60s, & 70s and control panels and consoles.
Author & Publisher - A Guide to Collecting Computers &
Computer Collectibles * ISBN 0-9684244-0-6
.
>Our library has volume 1 of a two-volume _Introduction to Programming_
>set. I've always wondered what was in the other volume. (It covers
>details of the languages supported on the PDP-8.) But I've never seen
>the two-volume set anywhere else, just a one-volume book.
The second volume was the _programming languages_ handbook.
>And while I'm at it... We have the OS/8 handbook as well. I've never
>been clear on what the different versions of OS/8 are, so I don't know
>how early or late our handbook is.
I'm afraid I can't speak to that... when I first used a pdp-8, it was
with 4k and an ASR33 -- it took too long to load editor, then assembler,
then linker by low speed paper tape, so we learned really quickly
how to hand-code and toggle the programs in through the front panel.
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
I've heard Xenodisk bandied about a lot. Would someone tell me what it is?
--
Jim Strickland
jim(a)DIESPAMMERSCUMcalico.litterbox.com
-----------------------------------------------------------------------
Vote Meadocrat! Bill and Opus in 2000 - Who ELSE is there?
-----------------------------------------------------------------------
> I have worked on various appliances ,electrical devices and/or wiring
> most of my life, close to 50 years, and I have been "bitten" on occasion.
> Of course, except for stoves and dryers, the voltage here is 110 v. I
can
> understand the respect given to 220v.(3wire) and have never worked on
> anything at that voltage without shutting down the circuit. I have also
been
> very cautious about working on anything in damp conditions like in a
> washroom or wet basement. I realize that it is the total amperage that
kills
> when you become ground. Most household circuits here are 15-20 amps.
> Having been "bitten" to no ill effects other than by my reaction to the
shock,
> what are the parameters which would kill you on these circuits. e.g.
rubber
> soled shoes vs leather, etc.
There is a common misconception that the amperage is what kills you. That
is simply not true. At low frequency (50-60HZ) and DC, the human body is a
simple resistive circuit and will obey OHMS law E=I*R. It is impossible to
have one without the other!
IIRC a current of approx 100MA through the trunk of the body is enough to
stop the heart. If you measure the resistance of your body and plug those
factors in the foumula, you'll get an idea of how much voltage it takes to
kill you.
The internal body parts actually have a fairly low electrical resistance.
This is because your body is filled with fluids that are somewhat
conductive. Most of the bodys resistance is due to the insulating
properties of your skin. Dry skin is a relatively poor conductor of
electricity but, when it is dampened the resistance becomes much lower.
That is why medical probes have a conductive jelly on them. The electrolyte
in the jelly breaks down the resistance of the skin and provides a better
path for current into the body.
A cars battery is capable of producing 100s of amperes of current however,
it won't fry you. When you touch the poles of the battery, the amount of
current (determined by the formula above), is very low and generally cannot
be felt. However, if your hands are damp, you could get a minor electrical
shock from it. NOTE: A shock from DC is a burning sensation rather than the
"vibrating" sensation of 60HZ curent.
There are a couple of ways to getting shocked when working on appliances.
Some more dangerous than others.
If you are working on a device and not well insulated from the ground,
there is a current path from your hand through your trunk (and heart)
directly to the ground. If you are foolish enough to stand in water while
doing this, the resistance through the soles of your feet is much lower and
the potential of a fatal shock is greater. Thick rubber soled shoes like
tennis shoes and isolation transformers are the best protection here.
If you are working with both hands, it is very possible to get zapped from
hand to hand. Once again the current path is directly through the trunk
(heart) of the body and is quite dangerous. That is why many electricians
work with in hand in their pocket. A shock that is isolated to one hand
could be painful but, isn't nearly as dangerous.
The worst shock that I have received was working on a antenna for a HF
transmitter. I was dumb enough to leave the equipment running while
adjusting the antenna and someone keyed the transmitter from a remote
location. A high frequency shock (like DC) is a burning sensation and I had
the blisters to prove it.
Steve Robertson - <steverob(a)hotoffice.com>
At 10:45 PM 2/23/99 -0800, George wrote:
>Is there still a source for 5.25 inch CP/M for the Xerox 820?
>
Will the CPM for the 803 or one of the other models work on the 820?
Does anyone know what the capability is between the various Televiedo models?
Joe
Whee! it's finally here! I got my vaxstation 3100 from Tim in the mail today!
It's a Vaxstation 3100 model 42 a-bd with a mighty 8 megs of ram.
It works, too! Tim thoughtfully loaded VMS 6.01 on the rz23 it came with, and
after hooking it up to my apple2GS with spectrum (also a classic computer :)
I got the thing to boot up into VMS. VERY cool. :)
Wishing it had TCP-IP, but heck, if it had *everything* I want on it,
where would the challenge be? :)
By the by, after attempting to negotiate with Sydex about a single user
license for Teledisk pro (the 150 dollar license they sell is a 25 user
site license) and failing, I've resolved not to do business with them again
and have removed Teledisk 2.16 (which turned out to be a hacked version)
>from my system as well as 22disk, which is their utility for copying to and
>from CPM disks. Good software, but not worth what they want for it. It's
DOS mode software for pete's sake.
--
Jim Strickland
jim(a)DIESPAMMERSCUMcalico.litterbox.com
-----------------------------------------------------------------------
Vote Meadocrat! Bill and Opus in 2000 - Who ELSE is there?
-----------------------------------------------------------------------
On Mon, 22 Feb 1999, Roger Merchberger <zmerch(a)30below.com> wrote:
> >> BIOTECH ELECTRONICS BCT800 graphics board - uses AMI 68047 chip and 12
>
> Erm, sounds like that AMI chip is a clone of Motorola's 6847 VDG, which
> was
> used in Tandy's CoCo 1 & 2, and the MC-10.
>
> I wonder:
>
> 1) if they're pin compatible,
> 2) if they've got added functionality -- might be fun to play with in one
> of my CoCo's if there is!
>
It's quite likely that AMI's 68047 is a clone of Motorola's 6847, because
AMI used to supply pin-for-pin equivalents of a number of Motorola
6800-family devices, including the 6821 Peripheral Interface Adapter and the
6850 Asynchronous Communications Interface Adapter. The 68047 and 6847 are
both 40-pin chips, but I don't have an AMI datasheet handy.
Arlen
--
Arlen Michaels amichael(a)nortelnetworks.com
Upon the date 04:35 PM 2/22/99 -0500, R. Stricklin (kjaeros) said something
like:
>On Mon, 22 Feb 1999, William Donzelli wrote:
>
>> Post 1960 CRTs are actually quite tough and will sustain a great deal of
>> physical abuse. When they break, the neck shatters first and lets all the
>> air in. The days of the nasty implosions due to no safety glass are gone.
>
>Hm. You're certain? I have this disembodied memory of seeing a box in my
>parents' shed in the early '80s, with an implosion hazard warning
>emblazoned on. I'm fairly sure it was the box for their old TRS-80 Model
>III, but it is possible it belonged to their Zenith TV they'd just bought.
>
>Maybe it was just a bozo-warning.
Yes it probably was a bozo-warning (I like that expression. Gotta remember
it. :)
I've handled CRTs since I was 11 or 12 (33-34 yrs ago). There were those
that were dead and had to be disposed of from a set I was repairing. When
throwing them into the town dump (that's back in the days before controlled
landfills and waste management laws, etc.) I was able to observe that they
would take quite a whack on the side of the large part of the envelope
before they broke. BUT, when they did break, the implosion caused glass
pieces to fly several meters distant. On the other hand, when just the neck
got broke, there was usually a definite, brief "chufff" sound when the air
rushed into the envelope and no other drastic action.
Here's a story to illustrate effects of an implosion: Back when I was
getting more and more into TV repairs during my 17th summer, there was a
dead 19" 110 degree deflection CRT that I had to get rid of. It was setting
on the ledge of the basement foundation wall. Dad was helping me sort out
and haul some junk to the dump. That CRT had to go in that load. Dad
figured he could simply break up that tube to save space on the load as we
were using the rather small family car to haul it (a '65 Corvair). Well, as
he'd never himself broke a CRT nor even seen what happens during an
implosion he was unaware of the "proper" way to bust one up. He held a
corrugated box under the edge of the wall where the tube was sitting,
grabbed a hammer and gave the side of the envelope a firm whack. Naturally,
just as I started to say "Don't hit it there!!", the deed was done. At
least knew enough to hold his eyes closed.
A few minutes later, after we both picked the broken glass out of our hair,
we observed that the largest piece of that tube was not even the size of a
fist. Mom came running downstairs and asked what in the world was going on
with that loud 'bang' and glass shattering sounds. Took a while to get the
place cleaned up. And you can bet that my mother was there watching us to
make darn sure we _did_ clean it up well.
Just understand the neck of a CRT is not so fragile to just break while
twisting a yoke after its clamp is loosened.
Use common sense while working around a CRT. Don't work in a tight area
where you could turn around and accidentally bump the neck with your elbow.
Have plenty room around the monitor while on the table or workbench. Don't
drop tools onto the CRT (happened to me once --and _only_ once!). Careful
of getting zapped by any unprotected parts of the yoke while under power
and rotating it (you could jerk around and bump the neck). There usually is
a part of the plastic yoke body with which you gould grasp while rotating.
The high voltage lead going to the ultor connection on the side of the
envelope handles about 15 to 18 thousand volts for a monochrome monitor.
Don't get close to the lead or especially the ultor connection.
Following these hints should help anybody here get through a simple yoke
adjustment like this.
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt(a)netsync.net
Member of Antique Wireless Association
URL: http://www.ggw.org/awa
