I have about 10 pounds (weight) of random cables which I believe where
used to connect two vax 4000 boxes. One end looks like scsi-2 but the
other is something similar but not (I think these connected the two qbuses)
Also there is a round cable with 2x3 .1" blocks (no idea, but related?)
a cable which looks like it goes from a 50 pin .1" scsi header to a centronics
scsi (hint: there is sharpie saying "8mm")
two cables which looks like giant multirow; I think these connected an outboard RX50
box to something else.
I was going to chuck these or put them on ebay. If anyone wants to pay postage
(10-12 pounds, from zip 02476 in the USA), let me know.
ps: I also have a vax 4000 box I no longer need with some disks and a cpu
if anyone *local* wants to come by and pick it up; it ran vms once.
send email off line if interested
-brad
> > I'm glad your not working on projects for me then. Having
> potentially
> > damaging voltage on a connector that is not needed doesn't
> sound like
> > good practices to me.
>
> I don't see it like that at all...
>
> I think Tandy were wiring the harness so any normal 8" drive sould be
> used. Some drives needed the 12V, some produced it internally
> from the
> 24V line, so Tandy provided it on the cable for those drives
> that need it.
>
> It's like PC floppy drives. Every PC I've ever worked on has
> 4 pin floppy
> drive power connecotrs : +_5V, +12V, and a couple of grounds. Most
> modern-ish 3.5" drives use 5V only. Are you saying that PC
> power supplies
> shouldn't connect up the 12V pin
I agree that your point is valid, but that's not the way I'd do it. If I were king it wouldn't be so, but I'm not.
>
> >
> > I have the service manual here for this drive. No where does it say
> > that pin 4 is not connected to anything. Nor do the
> > schematics I have show that this drive's 7812 (which is how it
> > is referenced in the print)
> > is optional. The only source for +12 on this schematic is the 7812,
> > derrived from the +24v line on Pin 1.
>
> Sure. That drive produces its 12V rail internally.
>
> Since you have the schematics, can you tell me what pin 4
> _is_ shown as being connected to, please.
Now you've got me. I didn't look at it from this point of view. There is no trace for it. Period, doesn't exist at all. Of course we all know that published schematics are all 100% correct (this is a dig at schematics in general, not you Tony). There isn't even a land for it on the circuit board on the drive I'm looking at. Physically, there are 5 black wires coming from the AMP plug to the circuit board. Pin 4 isn't poulated and there's no open land on the board.
>
> >
> > Tandy also uses the same connector on the same power supply wiring
> > harness, but with a completely different pinout (and using the same
> > color scheme in some instances) to provide power to the
> > card cage riser
> > IN THE SAME MACHINE. If you use this connector on the drive
> > instead of
> > the riser, bad things happen. If you use the drive power
> connector on
> > the riser, bad things happen. The only way to tell them
> apart reliably
> > is that the drive power cable has two connectors (to power
> 2 drives) and
> > the riser power connector has only one AMP connector.
>
> I rememebr one of the old Sun machines (Sun 2?) that used an Archive
> Sidewinder QIC drive. It has a 4 pin power connector, jsut
> like the one
> on a 5.25" drive. There's only one problem. The Sidewinder
> uses +5V and
> +24V. And IIRC the only differnce in the tape drive pwoer
> connector was
> the colour of thew wire to one pin.
>
Yuck. Then you know the pain.
Kelly
>> 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.
>
> I think that's a rather strange conclusion to some to.
>
> I'd think of it more like this ;
>
> Some 8" drives need the +12V supply, and when it's needed it's on pin 4
> of the connecotr. So Tandy wired the harness to allow for such drives.
>
> This particular Tandon drive doesn't need 12V, so pin 4 is missing (or a
> no-connect).
>
> How can _adding_ a wire to a harness be a shortcut?
>
> -tony
I'm glad your not working on projects for me then. Having potentially damaging voltage on a connector that is not needed doesn't sound like good practices to me.
I have the service manual here for this drive. No where does it say that pin 4 is not connected to anything. Nor do the schematics I have show that this drive's 7812 (which is how it is referenced in the print) is optional. The only source for +12 on this schematic is the 7812, derrived from the +24v line on Pin 1.
Tandy also uses the same connector on the same power supply wiring harness, but with a completely different pinout (and using the same color scheme in some instances) to provide power to the card cage riser IN THE SAME MACHINE. If you use this connector on the drive instead of the riser, bad things happen. If you use the drive power connector on the riser, bad things happen. The only way to tell them apart reliably is that the drive power cable has two connectors (to power 2 drives) and the riser power connector has only one AMP connector.
By the way, if anyone needs these connectors, they are stocked by Mouser and are about $3.50 each. Search for AMP 1-480270-0. I'm reworking a (different) power supply so I can put several TM848-2e drives in an enclosure for imaging disks from a PC. I also found 18ga hookup wire in 100' spools for less than $10 per spool at Jameco.
It may save some wiring, but I still think it is a poor practice.
William Donzelli wrote:
Keep in mind that there are costs beyond that dollar. Yes, the costs
of the parts is obvious, and the techs time is also pretty obvious,
but there is more. WAY more.
Doing more component level repair means more techs on staff. More
salaries. With more salaries comes more health care costs, more little
benefits, more equipment, more floorspace, which mean a bigger
building - and then there are the extra personnel people needed to
handle the techs - and their salaries, health care costs, little
benefits, equipment, floorspace - which means you need an even bigger
building, with more maintenance staff, and their salaries, health care
costs, little benefits, equipment, floorspace - which now with a
bigger building comes more property taxes, maintenance costs, material
handling equipment and the servicing they always need, and then the
new shelves to put the part, and the costs to erect them, which may
mean some temps or even more maintenance personnel...
OK, I could go on ALL NIGHT. Yes, the costs incurred for repairing
that little dollar part may have only tiny fractional effects on all
of the above mentioned stuff, but as things start to multiply, you
find that there is a lot of money being dumped into a department that
does not actually make any money.
--
Will
------------------------------------
Finally, a little reality comes into this discussion. Everything William
describes is normal for this industry. You will find it labeled different
ways, but it is real actual costs to support a maintenance organization.
(The last management textbook I saw called it MLB - materials, labour,
burden.) In Silicon Valley, MLB runs from 100% to 250% of the technician's
salary. In Asia, we can usually get it down to 80%, and the salary is
lower.
I think everyone who looks at this issue forgets that technicians are human.
They have needs. They like to be paid; they need tools and space; they only
work so long. To date, nobody has found a way to automate their skills. So
this overhead is a real cost to an organization. And to William's final and
most critical point - repair sections are not a profit and loss center.
They represent only loss - they do not generate income.
So if you set up a business making widgets and they can break and need
repair, you have to make a choice. Do you just replace them or do you fix
them? A repair department is a constant drain of money and resources.
Replacement-only can take advantage of the volume/cost curve. It is the
cheapest alternative.
It may look like you are wasting money, spending hundreds to replace 1-2
dollar components. But looking at the overall costs to a business, it is
extremely unlikely to economically viable to repair parts. You have to look
at the real cost to your business, and not the cost of failing element.
And for all of you who think this is a deplorable recent trend, you are
wrong. These same factors existed from the very beginning of the computer
industry. The cost of the maintenance on the very first systems was already
one of the biggest expenses faced by the companies. It was a major factor
in the demise of many of the early companies. They found their MLB
exceeding their profit; and they couldn't do much to change it, since it
doesn't create income. Even our favorite company here, DEC found that the
maintenance and support was by far the biggest department in the company.
Some third party companies like Bell Atlantic saw it as an opportunity. But
in the end, they all faced the same factors - huge MLB, low income.
So coming back full circle we have the hobbyists on this list who repair for
the love of it. They bitch about the lack of documentation or parts. But
they don't accept that the generation of documents, parts, reparability has
a very high cost associated with it. And there is no income associated with
creating those items. With all our high level skills, none of us got rich.
It is not a marketable skill in a world focused on profit.
Billy
The laptop served me as a terminal, after the flyback transformer of my
VT320 died. (Side info: there are new VT320 flyback transformers on ebay for
$4 each. But the news is too late for me.)
I was facing the question as what to do. Buy a real terminal? Buy another
8086-386 laptop? Buy a mac SE? Buy a small used IDE HD? Buy serial cable for
the HP 100LX I have? Replace the unreliable floppy drive?
After one hour of surfing the internet, I finally bought 4 IDE-CF adapters
(laptop and desktop versions, $2 each). One for the laptop, one for the
pentium PC linux router, one for the 386 desktop.
Just want to share the experience with you so you do not need to waste the 1
hour as I did.
vax, 9000
Regretably it never successfully made the transition from radio to TV or
film. Its not unique, many other radio shows had the same problem.
R
-----Original Message-----
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Fred Cisin
Sent: 26 January 2007 02:51
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: 42 (was: Component level repair
On Thu, 25 Jan 2007, Billy Pettit wrote:
> I stand corrected. All we saw here was the BBC television series
If you have a copy with six half-hour episodes, it is near the end of
the last episode.
> and rather
> abominable big screen movie a few years ago.
I didn't like that either. But, I have my own ideas about how it should
be cast:
Ed O'Neil as Arthur Dent
Howard Stern as Zaphod
Roseanne as the Vogon captain
Jaqueline Pearce (Servilan on Blake's 7) as Trillian Christopher Lloyd
as Slartibartfast, . . .
And I see Marvin as much more like Bender than like the Disney cute one.
I happened to luck into someone this week on eBay who recently put up
my OS/8 Adventure sources for sale.. he's offered to put the source
onto floppies from his system. However, all he has is a RX01 drive.
I've got some floppies around, but they may have been "formatted" by a
RX02. I don't remember if they're still compatible with the '01. Is
there any hope there, or anyone with a few (3) RX01 disks?
More importantly, is there anyone on the list that can dump a set of
files from an RX01 in OS/8 format so I can recover them? It'd be very
cool to have the RALF source back.
-Rick
* Fred Cisin explained:
> WhatdoYOUgetwhenyoumultiplysixbynine?
On Thu, 25 Jan 2007, Billy Pettit wrote:
> Philistines. Are there no Douglas Adams fans here? Life, The Universe
and
> Everything?
In the BBC screen play (written BEFORE the book, the letters from the
Scrabble bag spelled out:
WHATDOYOUGETWHENYOUMULTIPLYSIXBYNINE
-----------------
I stand corrected. All we saw here was the BBC television series and rather
abominable big screen movie a few years ago.
And of course we claim Douglas Adams as one of our own left coast
celebrities, since he settled in Santa Barbara when he made the big time.
California, heaven to those with the big bucks. Something else to those of
us who work here and have to drive to work everyday.
Billy
The recent talk about two old Displaywriters being up for grabs got
me to thinking about something that I've left hanging out in my
"things to do" list.
Does anyone know the internals of the Displaywriter file format? The
disks themselves are SSSD with the first track being 26x128 byte
sectors and the remainder 15x256. The encoding is EBCDIC for the
text, obviously, but the structure has eluded me (or I've been just
too lazy to figure it out). My notes from years ago say that it
appears to be a two-level sort of affair, with the top level
referring to documents and the second referring to pages within the
documents--and then I became distracted and that's where my notes
leave off.
Does anyone know anything more about these things? I'd like to close
this item out in my "things to do list'.
Cheers,
Chuck
