Hi all
>From: M H Stein <dm561 at torfree.net>
>
>If your friend is sure it's the CRT he/she must have had it apart; what's
>the number, size, etc.?
I havn't seen this animal myself, but questions yielded the following answers :
CRT is marked with the following numbers :
P/N95-P09122T001
P/N96/80396A98
AEG396512
D/14/390GH it could also be D/14/390GHB
(None of these pop up on google).
The size of the CRT is as follows;
L: 360mm
W: 100mm
H: 125mm
(I would regard these as approximate).
Ideas, anyone?
Thanks
Wouter
Is there a way to coldboot an apple III, if you do not have the SOS disks ?
On the apple II you can do it via the serial interface and the Basic
ROM, but the apple iii lacks these ROM's
Jos DReesen
New York Weekly Messenger 2-13-1833
Babbage Calculating Machine Article 1833
On the back page of this newspaper is an article that describes in some
detail the eye-witness account of a *working* machine: "...the greater part
of the calculating machine is already constructed....I have had the
advantage of seeing it actually calculate, and of studying its construction
with Mr. Babbage himself..."
Does this account describe a working computer? To help make this
determination I would want to learn more about the error checking
capability of this machine, which I assume was used for calculation of
significant digits. A described, Babbage's calculating machine could be
described as "computer-like" at least. I believe that this article reports
the closest Babbage got to a actual working computer. Or just an elaborate
calculator. There are no references in the article to what we today would
identify as punch cards or programming.
Download the PDF
http://www.vintagecomputer.net/babbage/charles_babbage_2-13-1833.pdf
...and read for yourself. The article describes error checking and how
results are viewed and how log tables could be calculated accurately, for
use in astronomy. The article noted that regarding the printer "..less
progress was made...".
In the 1830's news from Europe would take a few weeks to reach New York, as
boat was the only cross-Atlantic communications. Most articles in the paper
refer to end of December 1832 events, including the account of the
Calculating Machine.
Overall there was a lack of contemporary articles about Babbage's
calculating machine in 1832-35. I was able to find just the one often
quoted article by D Lardner: "Babbage's Calculating Engines" from
the Edinburgh Review 59 (1834) pg 263-327. The New York Weekly Messenger
article above was printed a year prior, making it among the first known
articles about Babbage's calculating machine. The apparent lack favorable
press and the loss of funding in 1834 obscured the fact that the machine
had a working visual "display" and was probably more complete than people
realize. Was the calculating machine programmable? Maybe. Most writings
about the Babbage projects were published a generation after the project
was cancelled and I don't think that it's possible to discount the notion
entirely.
> From: rdawson16 at hotmail.com
>
>
>> Date: Mon, 26 Nov 2007 13:15:02 -0500> From: ray at arachelian.com> To:> Subject: Re: *updating* 8088's>> Roy J. Tellason wrote:>> On Friday 23 November 2007 19:05, dwight elvey wrote:>>>>>> From: rtellason at verizon.net>>>>>>>> I notice that even those guys that are building relay computers "cheat">>>> and use a single small solid-state chip for RAM. :-)>>>>>>> Hi>>> I've been thinking about how one could make a reasonable>>> memory, using small reed relays. If one puts a magnet close>>> to one end, it will cause the reed to close. Move it back>>> some and it will hold until the field is too weak.>>>> ..>>>> Dunno if they still sell them or not, but Radio Shack used to sell a pack of>> 20 reed switches for only a couple of bucks...>>>>>> Hmm... Wonder if it's possible to build a relay without a spring on the> switch. That is, you have to send current with one polarity to set the> switch to a 1 and reverse polarity to set a zero - sort of what core> memory does with rings... I suppose this could instead be done by> attaching a magnet to the switch, or using magnet as the thing inside> the switch body, or better yet maybe a relay with a ball with a set of> contacts as the switch and two magnets, one on each opposite side...> you'd energize one coil for a "1" and the other for a "0">> Hmm, could even be done with a solenoid and use the mechanical part of> it to touch a wire for output. :-) Wouldn't really be a relay, but> pretty close.>>
>
>
> Teledyne makes a 'non volitale' relay. its tradename is Maglatch.
Hi Randy
I used to use these or similar in equipment while I was in the service.
They were not real reliable and expensive. They were in a state machine
control for a reel to real multi track tape.
Every now and then we'd take the control board out and smack it
several times onto the work bench. It would work fine for a few
weeks and then need another smack.
I assumed that it was related to the armatures needing to be demagnetize
every now and then. They used a bias magnet similar to what I've
been suggesting to work with reed relays.
One thing I learned about reed relays is to not use a weller iron with
the magnetic heater switch. The reed relay would not open. I'd use
that method if it was more controllable.
Dwight
_________________________________________________________________
Put your friends on the big screen with Windows Vista? + Windows Live?.
http://www.microsoft.com/windows/shop/specialoffers.mspx?ocid=TXT_TAGLM_CPC…
>
>Subject: Re: *updating* 8088's
> From: Dave McGuire <mcguire at neurotica.com>
> Date: Tue, 20 Nov 2007 11:43:02 -0500
> To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
>
>On Nov 19, 2007, at 11:03 PM, Allison wrote:
>> I build with 6 and 10mhz z80s and 12mhz 8085s I have and theres
>> little problem with finding static rams and Eprom (and EEprom)
>> that can keep up.
>
> Did you say 12MHz 8085? Holy cow! Tell me more?
I meant 6MHz, 12mhz crystal. However, even at 6 its fast.
FYI I tried overclocking a 80C856mhz part and it was still
doing well at 8mhz but I was seeing memory timing issues.
You don't see the 6mhz parts too often. The usual is the
3 and 5mhz and usually the -5 (5mhz) will overclock to 6
with no real issues.
At those speeds it's intereating as old 8080 software is
now at 3X!
Though a 10mhz Z80 is also a nice thing but the 85nS memory
need is something to aware of. That short M1 read cycle
preally beats up ram. Z180 is better and Z84S180s can be
found as fast as 33mhz.
Allison
>
> -Dave
>
>--
>Dave McGuire
>Port Charlotte, FL
>Farewell Ophelia, 9/22/1991 - 7/25/2007
>
>
Not exactly my Holy Grail, but a unit I hold in high
regard. Anyone have one (or more) surplus to their
needs (working or not). I actually have a line on one
already, but the guy is taking his time. Don't want to
bug him that much.
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-----------------Original Message:
Date: Thu, 29 Mar 2007 07:48:55 +1000
From: Doug Jackson <doug at stillhq.com>
Subject: Re: 2708 EPROM progreammer - old magazines designs
John S wrote:
> > As 2708s are obsolete few moern programmers support them, apart from a few
> > that cost many $100s. So I thought why not try and build one? I've found
> > references to the following classic magazines, and I would be willing to pay
> > a small fee for photocopies or scans of the articles:
> >
> > Program your next EROM in BASIC. Schematic for a 2708 erasable read only
> > memory reader and programmer which uses parallel IO ports to set data and
> > address. The software to drive the programmer is written in BASIC.
> > Byte - March 1978 page 84 on (main article)
> > Byte - April 1978 page 62 (Byte Bugs)
>
I have a programmer designed by Steve Ciarcia from BYTE - It uses an
8051AH-Basic (The 8051 with basic embedded) as the controller - and
still works a treat - to this day. - Standalone board, interface via
serial. It was fun to see peoples faces when you shipped a ^C down the
serial line, and dropped through to a READY prompt.
I can find the doco for yo, but it is a high end solution to a simple
problem.
Alternately, I'm more than happy to read an eprom for you, and email
contents - I'm in Oz though. Perhaps there is somebody in the US who
could do the same.
Doug
-----------------Reply:
I have one of those as well; alas, it does NOT do 2708's.
To the OP:
I can scan the KB article for you, but the 2708 programmer is
intended to work with a Motorola MEK6800-D2, and consists of
nothing more than 3 transistors to switch the 27V (and a couple
of switches and a socket for the EPROM). It's all done in software.
mike
Does anyone have a NOS screen for one of these things?
I turned mine on today and I like it, but it's a bit
worn out. Strange request it may seem, but I actually
have a brand new screen and k/b for IBM's first laptop
(I can't believe the name escapes me).
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