Wasn't the IMSAI case (and many others of the same era) powder-coated?
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On 16 Mar, 2008, at 17:52, cctalk-request at classiccmp.org wrote:
> It is difficult for me to give a precise date. I don't have any
> manufacturing notes/schematics about this machine. Published
> computer lists
> indicate 1965. But they don't know my work. It seems that the
> machine began
> a military career, before a commercial one. (My machine has a military
> color, and a customs seal)And I think that the 1965 date is only for
> commercial use (not reserved to military).Date codes on PCBs range
> from 1962
> to 1964. It's why I think 1964. But the machine was used for
> manufacturing
> problems debugging / ECN. 1964 may be the date of the last ECN...
> So the
> date is between 1962 and 1965.
Thank. I presume ECN means PCB = Printed Circuit Board.
> |It is tiny compared with my Germanium machine
> (ICT 1301) which weighs
> |five tons. It has the same clock speed but is quite a bit slower, so
> |I guess it is earlier than mine. But maybe the emphasis of the design
> |was miniaturisation and the designers traded speed for size.
> |
I should have made it clear that it is the 1301 which is the faster
of the two. For example a 48 bit decimal (i.e. 12 digits) add to /
subtract from a register takes 21 microseconds.
>
> What is the manufacturing date of your ICT 1301?
Actually I have two. Serial number 6 was the first one to be sold and
was installed in 1962 and it is this one which is assembled and
works, though not all the peripherals are functional. Serial number
75 I would guess was made in 1963. I have a few parts of serial
number 155, which I would think would be from 1965 when the machines
were largely replaced by the ICT 1900 series. Designing of the
machines was started in the late 1950s, and many of the engineering
drawings have initial revisions from that period.
The architecture of your machine reminds me of the first machine I
was allowed to operate. It was an 18 bit binary machine, it had 8k of
memory built in, expandable with external modules and was made by the
Airborne Computing Division (ACD) of Elliotts, it was an Elliott 920B
and was a compact, flyable version of the commercial Elliott 903.
There had been an earlier model 920A which I think would have been
Germanium and was roughly the size and shape of a carpenters work
bench. This may have been contemporary with your earlier machine I
think. Unfortunately I never saw one in the flesh, but there was a
bench in the computer room which I found out later, was the empty
chassis of a 920A. Behind the bench was a large panel full of
electrical 'chocolate strip' connectors where the analogue and
digital input and output signals of the 920A could be connected up.
Apparently some of the analogue outputs had been connected up to an
oscilloscope to provide a visual display unit, though it used a fair
bit of processor time to keep it refreshed, even with the long
persistence phosphor of an oscilloscope. The panel had been covered
with board with pegs to hold mylar paper tapes and until the day it
was scrapped I had not seen what was behind it.
> I have a
> earlier machine from the same company SEREL, named OA-1001. Built in
> 1959/1960.I need to restore it. It lays on the floor (horizontal
> position)... The blue one
> here:http://pichotjm.free.fr/Serel/Photos/Photos.htmlI will start
> restoring
> next month (with the Sun!)
What is involved in the restoration? Do you intend to make it work,
this would be very hard without the schematics.
Roger.
Hello
does someone of us know the pantone or RAL reference of the blue paint on the IMSAI 8080 cover?
I want to repaint mine but i don't find the exact reference of this blue.
Many thanks in advance
Charles
Dear Sir,
I?m in trouble with the system as the boot stops at :
RSX-11M - Plus V4.3 BL66 2044.KW System "Pt/Ps"
> RED DU:=SY:
when loading from RD53 (RZ 28M-E)
and stops at:
RSX-11M/RSX-11M Plus Standalone Copy System V03
when loading from RX33 (Brusys floppy)
Do you have an idea why the boot does not go on?
Thanks in advance,
Henrique Gomes.
Date: Sat, 15 Mar 2008 13:06:36 -0700
From: dwight elvey <dkelvey at hotmail.com>
Subject: RE: UARTs (was: Switch settings: Facit 4070 tape punch)
>> According to the Marketing Memo from GI announcing the discontinuation
>> of the AY-5-1013, the -A replacement is identical except for the higher max
>> baud rate (in fact, it is a 5-1013 that has been tested to 40kb instead of 30).
>Hi
> For AY-5-1013 to AY-5-1013A, I reference the table on page ten of the document.
> I don't disagree with the maximum rates but the table does show different stop bits.
> For most users, of old systems, 1200 or 9600 was maximum so the top rate of
> the part is of no special value.
> Dwight
Not to belabour the issue, but since cross-references are notorious for their
inaccuracies I think I'll go by GI's AY-5-1013/A datasheet, especially since
they made a point of issuing a bulletin to their customers assuring them that
the 5-1013A was in fact a 5-1013 selected for the higher baud rate. Also
notice that this part was marked on your cross-reference with a note
to consult the factory for detailed interchangeability information.
Other cross-references list these SMC equivalents:
AY-5-1013 COM2502
AY-5-1013A COM2502H (not 2017)
And it makes more sense that the same number with a different suffix would
indeed be the identical part with a different speed.
(e.g. http://tvservice.org/components/CROSSREF.PDF)
Finally, GI part numbers are easily confused. As an example, if you want
to look at the AY-5-1013A data sheet to convince yourself that it is indeed
a 1 & 2 stop bit UART, you will find it at datasheetarchive.com and
alldatasheet.com, but listed as an AY-3-1013 at the former, and AY-3-1013A
at the latter (neither of which, AFAIK, was ever a valid GI part number).
I just wanted to set the record straight in case someone for whom it's actually
relevant reads this thread some day.
m
> dwight elvey <dkelvey at hotmail.com> writes:
>
> >> 3.595295 MHz
> > TV color crystal frequncy.
>
> No, that's 3.579545 MHz (or 4.43361875 MHz for PAL) -- this one's a
> bit faster than the NTSC colourburst, which presumably is what makes
> it unusual...
3.595295 MHz is the color burst frequency (3,579,545) plus, EXACTLY, 15,750
(the horizontal scan rate). This crystal is used to produce a "rainbow"
(normally a "gated rainbow") color test display. Going from left to right
it continuously changes color through all 360 degrees of the color burst.
[I'm kind of surprised that it's CB+15,760 instead of CB+15,764 ... the
horizontal scan frequency for COLOR is bumped up slightly from 15,750 to
15,764].
> Any words of advise before I crack the case open and void the warranty?
>
Be careful of the tube neck when taking off or putting back the top of the shell. I've broken one myself. I think I have ONE more spare, but I'm hanging on to it.
The CRT is fastened to the top shell, and it is precariously close to the main board and mountings in the back.
Kelly
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I have put together a web page listing some service manuals and other
literature that I'm looking to part with, here:
http://mysite.verizon.net/rtellason/manuals.html
More will be added as I get the chance, but that's a large part of it. Feel
free to contact me via email if you have any questions.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
>>> Is a IBM 5140 considered a Classic.
Assuming that you mean "is it considered on-topic," then, yes.
The 5140 "Convertible" (1984) was IBM's first laptop and is a nice example of creative engineering from the early days of laptops overall.
I met the person who designed it. One if these days I'll get around to interviewing him...