On Sat, 2009-02-28 at 14:23 +0000, Robert Jarratt wrote:
> Some have suggested it blew because I had insufficient load. I had a TK50
> and an RD53 attached, would that no be sufficient. Furthermore I did not
> actually switch the PSU on, just connected it to the mains, would the load
> connected to the PSU matter when the PSU is not actually switched on?
I'd use a "modern" old hard disk, not one that's likely to be useful.
Or a couple of car indicator bulbs.
If it was plugged in but not switched on and something popped, it'll be
the mains filter cap. They *do* fail, and they're easy to replace.
> There was also a suggestion that the PSU would have needed switching
> separately for 50Hz operation as well. The hardware manual I have for the
> machine tells me how to switch between 110 and 240, but does not say
> anything about switching it for frequency, so I suspect this was not an
> issue here.
It won't have a 50/60Hz switch, just voltage.
Gordon
I don't know anything about the PDP-11 MIMD machine at CMU other than
seeing references to it while researching the PDP-11 in general.
I saw a picture on wikipedia and wondered if anybody knew the eventual
disposition of this machine. It seems like a recent picture. Hopefully
it is a destined for preservation.
The cage makes me think of a prisoner awaiting his last walk down the
"green mile"....
-chuck
http://en.wikipedia.org/wiki/C.mmp
Thining of edge-punched cards...
The original membership cards for the Cambridge University Computer
Preservation Society had 8-level paper-tape punchings along the bottom
edge giving (IIRC) 'CUCPS' (im ASCII),. the member's computer userid
(ditto) and the membership number (3 bytes, binary).
I don;t think anyone ever tried to machine-read them though.
-tony
According to a datasheet[1] I found, a Siliconix DG506AR is an analogue
switch in CMOS. What are some applications for this? I found a pair of
them in white ceramic in my junk pile and I don't know where they came
from.
[1]
http://www.datasheetarchive.com/pdf-datasheets/Databooks-4/Book-27459.pdf
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
I just sent a confirming email out to all of you who wanted to join the
group purchase of Emulex UC07, Qbus/SCSI boards.
NOTE: If you did NOT receive a confirming email - and you had previously
sent me an email order by Thursday (3/5), please get back to me ASAP so I
can include you in the purchase.
Cheers,
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
http://bickleywest.com
"Black holes are where God is dividing by zero"
________________________________
There is/was an IEEE standard for the S-100 bus; why not hew to that,
regarding supply voltages?
If I were designing new "retro" boards today, however, I'd go with
one of the switching regulators that can be had in TO-220 packages.
Basically the same appearance as the veneered and generated 7805, but
far more efficient.
Cheers,
Chuck
-----REPLY-----
Hi Chuck! Yes, the S-100 crates I have at home all use +8V and 18V/-16V
rails from the linear power supplies. I understand where the power standard
came from and agree the standard values would be the ideal solution.
However I am working on a low cost small S-100 backplane project and I'd
like to know what flexibility I have with regards to power supplies in order
to keep costs low.
8V SMPSUs aren't exactly common these days and you'd need at least one of
those and another 18/-18V SMPSU for a S-100 backplane to work properly.
Practically speaking, the linear power supplies are unregulated and generate
a range of voltages probably in the 8-10V range as Allison mentioned. I am
thinking a 9V and a pair of 15V SMPSUs might be just good enough to work if
not a long term solution.
Since my goal is to keep costs low I am trying to find less expensive
options and still have a useable system. The intent of the project is a
small bench unit for testing and repair of S-100 boards but not a full blown
system. I agree with Barry and Dwight to keep the voltage rails just about
3V above the 7805/7812 SCRs output for efficient regulation without
excessive heat. However, 9V SMPSUs are really common and cheap on eBay and
could be readily converted if not optimal, at least they'd be useable for a
while without destroying anything. Add a pair of 15V SMPSUs and for less
than $50 you'd have a usable S-100 PS system. I don't think you could make
a S-100 linear PS for that low cost. Maybe I could put a high current
silicon diode in line with the 9V SMPSU and drop it to like 8.4V? That'd be
closer to the 8V standard.
I posted a schematic and PCB layout on the N8VEM wiki but whenever I post
the URL to CCTALK it never makes it to the list. I suspect it's being spam
filtered or something. I believe the actual useable ranges of the S-100
unregulated power supply is about 8V to 10V, 15 to 20V, and -15 to -20V.
For current capacity since the PCB is only 4 slots, I am thinking on the
order of 1V per slot should be sufficient. There are some older S-100
boards that will exceed that limit like those massive 8K SRAM boards but if
you are working on one of those probably not all the slots would be used.
At any rate, I am swamped with my current N8VEM related projects and the
S-100 backplane project is on slow simmer for a while.
Thanks and have a nice day!
Andrew Lynch
As a matter of fact Cromemco's later systems easily ran 68020s at 16.7 MHz on
their S-100 / IEEE696 bus backplanes.
mike
*************************************
Date: Thu, 5 Mar 2009 19:21:53 -0800 (PST)
From: Michael Hart <imsaicollector at yahoo.com>
Subject: RE: S-100 power supply voltage ranges
CompuPro and Cromenco were state of the ART IEEE 696.
The back place was supposed to be able to handle higher than a wopping 10MHz
Michael Hart
Trader Kiosk
201-290-3796
michael at traderkiosk.com
imsaicollector at yahoo.com
I, the unwilling, was led by the unqualified, to do the unbelievable for so long with so little, that I attempted the impossible with nothing......"
--- On Thu, 3/5/09, Chuck Guzis <cclist at sydex.com> wrote:
From: Chuck Guzis <cclist at sydex.com>
Subject: RE: S-100 power supply voltage ranges
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
Date: Thursday, March 5, 2009, 10:11 PM
On 5 Mar 2009 at 18:56, Fred Cisin wrote:
> But, . . .
> would the standard, even early versions, such as presented by George
> Morrow and Howard Fullme at the West Coast Computer Faire, really embody
> the SPIRIT of S100 without at least a few non-standard signals?
Heh. Was it the SOL-20 that tied the Data In and Data Out lines
together?
Would you consider the late Godbout/Compupro boxes to be the height
of S-100 development?
Cheers,
Chuck
I have an old Roland DG CC122 (switchable IBM/Apple) CGA colour monitor
and I was wondering if anyone here had any information on it.
Trying to find out if it has a monochrome mode for a test fixture
application...
Thanks,
John :-#)#
Hi all,
I have the following items that are looking for a new home.
Tektronix 9100 DAS manual
SCO Xenix manual set w/Excelan "The LAN Workplace" manual & disks
Books on 1-2-3 & dBase
Misc hardware manuals (PC)
Pictures are available here: http://www.flickr.com/photos/jja572
Make me an offer above shipping cost to make it worth my time to box it up. Anything not claimed in the next week or so shall most likely end up in the recycle bin.
More to items to come in the near future.
Jon
One of the things that I'd have liked to do with my Osborne Executive is to
put double-sided drives into it. That single-sided nonsense was always an
irritation. :-)
The problem with this is that I don't know if there is a "standard" format for
this. Maybe what the O-3 (Vixen?) used, perhaps? I know that had DS drives
in it.
One thing I'd need even if I dropped a couple of DS drives in there is to be
able to format DS disks. Which means I'd need source code for their
formatting utility.
Does anybody know what happened to this stuff when Osborne went under? Who
bought that stuff up? Where such source might be found? Or if it even
exists?
--
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
