I've been active on classiccmp for a good many years now and up until now
have rather enjoyed making custom and hard to find cables for others in
the classicmp community.
Recently, someone on eBay managed to get their hands on a spool of genuine
DEC flat cord, bought a knock-off MMJ type tool (I saw him purchase it)
and started selling poor quality MMJ cables.
I couldn't compete and quit making standard MMJ cables, but this weekend
he started making H8571-J work-alike adapters to undercut me there too.
I know this person is active on the classiccmp mailing list. He started
listing his cables shortly after my post when I asked which length of MMJ
cables would be the most useful to the majority of the list members.
His eBay id is currently "cheshire-cat-computers" but he had been going by
"ggggmmmm" up until Jan 5th. I've been going in the hole now for 2-3
months with the listings for cables and I think after today I won't be
listing any more. I've now run out of 6-conductor flat cable and I'm down
to less than 2 dozen loose MMJ plugs and I'm thinking that its just not
worth the trouble anymore. I still have some adapter kits that I made up a
few weeks ago, but I think I'm just going to toss them in the junk box and
forget about them. I just have no desire to compete with someone who wants
to undercut me the way he has done as it appears my time is worth a lot
more to me than his is to him.
It was certainly fun while it lasted, and I shipped cables all over the
place, from Australia to Germany to the UK, and of course the USA and got
to talk to all kinds of people. I even had a few go to a couple of people
in the armed forces, so I guess they are still using DEC gear too :)
-Toth
Re: "would it be possible to get a 5.25 to work in say an older laptop w/an
integral 3.5?"
Maybe.
Quite a few Toshiba laptops have an external floppy drive port. It is a
true floppy port, designed to interface to a 34-pin floppy interface. Two
different connectors were used, the "standard" Toshiba floppy port connector
used in every model computer except the Tecra 8000, and a slightly different
connector used in the Tecra 8000 series.
These connectors are found in the Satellite 400 series laptops (two
distinctly different sets of laptops, the "early" 400 series (400 to 435,
Pentium I's) and the "late" 400 series, 440 to 490, Pentium MMX and even a
Pentium II). They are also found in the Tecra 8000 (different connector),
which used both Pentium II and Pentium III CPU (266MHz to about 500MHz). I
think that there are other Toshiba laptops that have a similar connector as
well, in the Tecra and Portege line (and also the libretto models).
Note, since this port was used for the 3.5" floppy drive, you generally
won't be able to have both 3.5" and 5.25" drives installed at the same time
(but, on some of these, the very reason for the port was that there was an
internal drive bay that could either contain the floppy drive internally, or
a CD-ROM drive. Not sure if you could use an internal and an external
floppy concurrently in those models).
Also, Toshiba assumed that the external drive was 3.5" and there is no
provision in the BIOS to configure the bios and software for any other
floppy drive format.
Finally, the hardware reconfiguration (cable) will be a bitch to figure out,
although it is conceptually possible. While the external floppy has the
34-pin electrical interface, mechanically it's not a standard 34-pin IDC
connector, it's a flat "flex cable", and reworking the cable to connect to a
34-pin standard interface will take some effort.
The good news is that you can buy entire laptops in this series for as
little as $15, and you can find the external floppy caddies for $5 (source
of the cable and connector that mates with the laptop).
Date: Wed, 24 Jan 2007 04:56:58 -0500
From: "Kelly Leavitt" <kelly at catcorner.org>
Subject: RE: Tandon TM848-2 Floppy drive power
To: "General Discussion: On-Topic and Off-Topic Posts"
> On Tue, 23 Jan 2007, Kelly Leavitt wrote:
> > OK, I'm home looking at the drive. The wiring harness from the power
> > supply does connect +5, +12, and +24 to the plug that goes into the
> > drive. However the TM848-2 drives have pin 4 vacant on the
> connector on
> > the drive. That is, there is no pin there. Sounds
> dangerous, but that is
> > typical of Tandy's shortcuts.
>
> Tandy and Tandon are not THAT close.
>
>
>
The wiring harness is made by Tandy, in the Tandy 6000. That this harness has power going to a drive power plug that isn't used it typical of Tandy's shortcuts. They banked on the fact that Tandon would NEVER put another pin in that socket.
----------------------------------------------------------------------
Well, in all fairness to Tandy...
Since the schematic for the TM848 shows what seems to be an option
to omit the 12V regulator and supply the 12V through the power plug,
perhaps Tandy at one time used (or planned to use) drives requiring 12V
and kept the 12V supply on the connector for compatibility. Wouldn't be
a problem since that pin is physically missing on "normal" drives.
Sorta makes sense; in the S-100 world there generally wasn't a 12V
supply and every drive needed its own regulator(s), whereas if a system
already had a 12V supply then using the 24V and another regulator on
the drive would be redundant and just waste power.
And there are certainly numerous custom versions of the TM848 around,
so you can't count on any particular drive being plug-compatible anyway.
Yes, if you happened to plug a drive with the power off option on pin 4
into your 6000, there probably would be some magic smoke...
Things weren't quite as "standard" in those days as they are today,
FWTW.
m
At 18:30 -0600 1/23/07, Richard wrote:
>Fine. Its shared by two or more people, but its still an opinion and
>not an axiomatically derived fact.
What's an "axiom"?
--
Mark Tapley, Dwarf Engineer
(I haven't cleared my neighborhood)
210-379-4635 Dwarf Phone, 210-522-6025 Office Phone
I *finally* had enough time to write the manual for the UA11 Unibus
Analyzer, so it's now available for sale. Go to
http://www.shiresoft.com/products & http://www.shiresoft.com/docs for
more information.
I now use it almost exclusively for debugging problems and getting
systems to work. I only pull out the 'scope or LA if the problem isn't
observable on the Unibus. (sorry, hopeless plug.)
--
TTFN - Guy
> In many ways, as I watched Lisa Office System and MacWorks boot up (via
> trace logs), I saw many glimpses into the software design ideals and
> practices of the early 80's. I've never been an archaeologist, and
> don't really know that experience, I can guess at the rush and thrill of
> discovery. Seeing the machine code of various Lisa OS's fly by has been
> that experience for me. I could almost understand what the coders that
> wrote them were thinking, how they designed things, and why. I could
> easily tell what code was hand written assembly by an expert, or novice,
> what assembly was generated by compilers.
PLEASE write document the details while this is all fresh in
your mind.
> From: Jules Richardson <julesrichardsonuk at yahoo.co.uk>
> too keen to process it on their own soil. Sooner or later there will
> (thankfully) be pressure on manufacturers to make their products be more
> maintainable and last for longer.
The way things are going, being able to maintain a buggy whip won't be
economically feasible or an asset to any mainstream company. Technology changes,
evolves, and rarely results in something being simpler and easier to fix.
I do like repairing at the component level, but just don't have time for it
right now. But as Tony mentioned, it is a puzzle, and the MINDSET that allows
troubleshooting is just not something everyone has.
One of my favorite examples was back when I was doing field maintenance, I got a
call from a customer who couldn't get their machine to work. So I flew down to
take a look, was picked up by the plant manager, and taken to the machine. While
he went to get the tech, I looked at it and had it working in a couple of
minutes later when they returned. The problem was strictly mechanical (an air
cylinder shaft had come unscrewed from the piston), and they had *assumed* it
was an electrical problem.
And most of us (at least those of us do/did troubleshooting as a job) have had
the experience of troubleshooting equipment where the problem turned out to be
the switch needed to be turned on, or the unit plugged in.
Developing a mental picture (I think in terms of block diagrams) of how
something works is crucial to being able to troubleshoot it.
Sounds like it's a 2011-C34. First Generation IBM PS/1. Uses matching VGA
monitor with CPU power supply inside and DOS in ROM. Kinda cute, and have heard
of some individuals still using them because they're pretty simple. I'd take i
t, but I already have one including the 2121 386 series.
-+-+-+-+-+-+-+-+-+-+-+-+-
In a message dated 1/24/2007 12:18:41 A.M. Eastern Standard Time,
cclist at sydex.com writes:
On 23 Jan 2007 at 17:47, Sellam Ismail wrote:
> I'm not sure if this interests anyone. It sure doesn't interest me, but
> maybe someone is looking for one to complete their collection. Have at
> it!
What might make this worth someone's collection is, I seem to recall,
that it is unusual in that it has PC-DOS in ROM.
Cheers,
Chuc
> -----Original Message-----
> From: cctalk-bounces at classiccmp.org
> [mailto:cctalk-bounces at classiccmp.org]On Behalf Of Fred Cisin
> Sent: Tuesday, January 23, 2007 11:22 PM
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: RE: Tandon TM848-2 Floppy drive power
>
>
> On Tue, 23 Jan 2007, Kelly Leavitt wrote:
> > OK, I'm home looking at the drive. The wiring harness from the power
> > supply does connect +5, +12, and +24 to the plug that goes into the
> > drive. However the TM848-2 drives have pin 4 vacant on the
> connector on
> > the drive. That is, there is no pin there. Sounds
> dangerous, but that is
> > typical of Tandy's shortcuts.
>
> Tandy and Tandon are not THAT close.
>
>
>
The wiring harness is made by Tandy, in the Tandy 6000. That this harness has power going to a drive power plug that isn't used it typical of Tandy's shortcuts. They banked on the fact that Tandon would NEVER put another pin in that socket.