14 Feb
2002
14 Feb
'02
5:04 p.m.
If these computers were still useful and interesting,
they wouldn't be
candidates for the crusher. Likewise, if there were any real value in those
cars to which you refer, someone would figure out a way to profit from them.
If they look good, it's probably the typcial "appearance over substance."
That is SO not true. (was this flame bait? did I just fall for it?!?)
For instance, there is a perfectly good, running 1992 Toyota Celica
sitting in my fire department lot waiting for us to tear it apart. It
runs, fine... the only thing wrong with it is the catalytic converter is
bad so it fails emissions testing during inspection. The owner used that
as an excuse to buy a new car, and donated this one to us. Book value,
$4,000.
We will be tearing it to shreds Wednesday and then our scrapper will haul
it off to his yard on a flat bed.
So no... just because it has real value, doesn't mean it will be used for
that value.
Frankly, I am a little amazed you can participate on a list like this and
NOT have an intimate understanding of how many perfectly usable computers
are sent to the junk yard all the time. (I have a garage full of working
LC5xx macs that are being cleaned up and given to people that can't
afford a computer... they were all pulled from a school dumpster... if
they hadn't been pulled out by a wise computer enthusiast, they would be
in a land fill by now)
-chris
<http://www.mythtech.net>
14 Feb
14 Feb
6:36 p.m.
The car that can't pass emissions is like the computer that won't run. It's
of no real use, except maybe for parts. (have you tried to salvage parts from
a computer lately?)
I wasn't trying to start a flame war, but there are lots of perfectly useable
PC's (you know, the ones with 640KB of RAM and no HDD) out there. They still
do everything a PC ever did, and a lot more than the mainframes of 1960 did.
What should we do with them? Once people don't want them any longer, whether
they're still functional is entirely moot. If someone's interested in 'em,
well, that's why there's this list. There are lots of totally obsolete
computers in the world, ones that we all OOh'd and AAh'd at back in the
'70's
and '80's and while they were really expensive and "cool" back then
they're
not terribly interesting to most folks now. I'd say there are probably more
old PRIME's out there than people who want 'em. I remember taking apart a
front panel from one, which I fished out of a surplus vendor's dumpster, just
to get the LED's.
Dick
----- Original Message -----
From: "Chris" <mythtech(a)Mac.com>
To: "Classic Computers" <classiccmp(a)classiccmp.org>
Sent: Thursday, February 14, 2002 9:04 PM
Subject: Re: Destructive charities (was: STAPLES STORES...)
>If these computers were still useful and
interesting, they wouldn't be
>candidates for the crusher. Likewise, if there were any real value in
those
>cars to which you refer, someone would figure out
a way to profit from
them.
If they look
good, it's probably the typcial "appearance over substance."
That is SO not true. (was this flame bait? did I just fall for it?!?)
For instance, there is a perfectly good, running 1992 Toyota Celica
sitting in my fire department lot waiting for us to tear it apart. It
runs, fine... the only thing wrong with it is the catalytic converter is
bad so it fails emissions testing during inspection. The owner used that
as an excuse to buy a new car, and donated this one to us. Book value,
$4,000.
We will be tearing it to shreds Wednesday and then our scrapper will haul
it off to his yard on a flat bed.
So no... just because it has real value, doesn't mean it will be used for
that value.
Frankly, I am a little amazed you can participate on a list like this and
NOT have an intimate understanding of how many perfectly usable computers
are sent to the junk yard all the time. (I have a garage full of working
LC5xx macs that are being cleaned up and given to people that can't
afford a computer... they were all pulled from a school dumpster... if
they hadn't been pulled out by a wise computer enthusiast, they would be
in a land fill by now)
-chris
<http://www.mythtech.net>
16 Feb
16 Feb
8:41 a.m.
No that's the corporate view. Profits First ! Irregardless as to what it does to
the environment. The balance sheet result is irrefutable. People and their
"quality of life" are not a component of the equation.
Lawrence
Wow, I can tell your not a car person!
Chad Fernandez
Michigan, USA
Richard Erlacher wrote:
Reply to:
lgwalker(a)mts.net
The car that can't pass emissions is like the computer that won't run. It's
of no real use, except maybe for parts. (have you tried to salvage parts from
a computer lately?)
15 Feb
15 Feb
1:19 p.m.
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3:07 p.m.
Quothe Tony Duell, from writings of Sat, Feb 16, 2002 at 12:19:06AM +0000:
Incidentally, am I the only person who's raided
useful stepper motors
from old floppy drives with worn-out heads?
Stepper motors, components, bits of metal, wire, screws, etc. are all
useful things to be found in such drives.
OK, most people here probably aren't interested in
non-name generic PC
clones.
Even if the generic clones aren't interesting, one can: use them as
terminals, use them as electronics test equipment, take them apart for
screws, nuts, components, PSU, connectors, disk drives, floppy drives,
etc. Use the cases as garden decorations, or... for some real fun,
save the empty cases and glue them to the exterior of your home,
eventually covering all of the external walls with them, perhaps
painting them different colors or all flat black. Use some bailing
twine to string some of the metal cases up in a tree and use them as
wind chimes. The metal cases would also make nice chasis for
home-brew projects using vacuum tubes or valves.
But the sort of machines that the charities won't
be able to
handle are _precisely_ the machines we are interested in. You know,
minicomputers, workstations, unix boxes, and so on.
These need to be saved, but will most likely be scrapped first,
thought to be the absolutely least useful by those who only recognize
PeeCees to be computers.
--
Copyright (C) 2001 R. D. Davis The difference between humans & other animals:
All Rights Reserved an unnatural belief that we're above Nature &
rdd(a)rddavis.org 410-744-4900 her other creatures, using dogma to justify such
http://www.rddavis.org beliefs and to justify much human cruelty.
4:21 p.m.
On 15 Feb 2002, R. D. Davis wrote:
As a matter of fact, I have an HP B132L [1] sitting in my garage that
I rescued from a local second-hand/surplus shop's trash can. Somebody
brought it in for trade, and they raided the drives (RAM was already
gone) and threw it away. I asked the counter-d00d "what's up with the
HP?" and he says "If you want it, it's yours. But it won't run
Windows." When I said "That's good!", he looked shocked.
[1] Sooner or later I'll break down and borrow some memory to test it.
I've run across so many intact machines lately that the "kits" are low
on the list.
Doc
But the sort
of machines that the charities won't be able to
handle are _precisely_ the machines we are interested in. You know,
minicomputers, workstations, unix boxes, and so on.
These need to be saved, but will most likely be scrapped first,
thought to be the absolutely least useful by those who only recognize
PeeCees to be computers. 
5:15 p.m.
----- Original Message -----
From: "R. D. Davis" <rdd(a)rddavis.org>
To: <classiccmp(a)classiccmp.org>
Sent: Saturday, February 16, 2002 12:37 PM
Subject: Re: Destructive charities (was: STAPLES STORES...)
Quothe Tony Duell, from writings of Sat, Feb 16, 2002
at 12:19:06AM +0000:
Indeed. I am in the process of making a pc controlled pan/tilt head for a
webcam using bits gleaned entirely from 5.25" drives.
By using the stepper controller and some of the sensors that already exist
in the disk electronics it can interface directly to a parallel port that I
control with software written in my (classic? must be close.) 'old but good'
Turbo Pascal 6 for DOS.
By judicious use of the drive select lines, it's possible to control several
'drives' from the one port so a pan and tilt plus (say) focus or something
similar is possible. Got plenty of half dead 5" drives, prefer the older
Chinons as they have huskier stepper motors with conventional shafts, the
really small steppers with the worm threaded shafts are harder to
mechanically interface and a bit feeble as well.
I have a really husky one pulled out of a huge old 9pin printer that I'm
saving for an antenna rotator with computer control. I want a 2M antenna to
follow the International Space Station for packet radio purposes. At
14v/700ma per phase, it's a brute. I tried driving it as an alternator with
a slow dc motor and got 44v out of it! 1.8deg per step, so if I half step
it I can get better than 1 degree resolution. Will need to build an
appropriate driver board, it would toast a floppy drive stepper controller.
The development box is a 386sx diskless ultra compact with 8mb of ram which
I have a dozen or more of. (dumpster bound at the school I work at) so they
will be dedicated, one to each web cam. Hope to make each workstation/cam
remotely controllable over an ip network. The software still works under
server based Win3 (95/98 too butnot XP , it runs, but the port gets nothing)
so might even use VNC or similar. This is even on topic as the 386sx
diskless box is 11 years old now. Very nice for playing with dos software
on, netboots off my Novell server, no drives of any kind to bother about.
Very small box, around 14" long, 9" wide and about 3" high. It's
sitting on
top of the CRO with the lid off as I am powering the butchered disk drive
Incidentally, am I the only person who's
raided useful stepper motors
from old floppy drives with worn-out heads?
Stepper motors, components, bits of metal, wire, screws, etc. are all
useful things to be found in such drives. from the 60w psu. Powering it from a separate supply
creates earth looping
issues that confuse the hell out of the logic by lifting the
pulled down
voltage about .4 of a volt, which is just enough to make it look like it's
not a low. Still working on that issue, but if it runs from the driving
pc's supply it works fine. Can also toggle the 300/360rpm spindle motor,
but am yet to figure out a use for it. Windscreen wiper?
Cheers
Geoff in Oz
16 Feb
16 Feb
8:24 a.m.
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9:06 p.m.
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Sunday, February 17, 2002 5:54 AM
Subject: Re: Destructive charities (was: STAPLES STORES...)
Yes, either for experimentation/reuse or to fix other machines.
I have a complete XT, keyboard and monitor (true blue) in my collection too.
I started playing with tp around V5 around 1990.
Yes, if I hadn't that would explain it, but tried it with/without and
several variants inbetween, still getting .4v pull up that stops the logic
recognising a low. Working around it at the moment, but will come back to
it when I have the interface and control stuff working properly. I have a
theory that it may actually be due to a minor fault in the drive
electronics, so I will test that later in the week with a substitute drive
board. I have compiled a test program that spins the motor both ways,
toggles the spindle motor on or off, and another section that lets me toggle
the direction of the stepper and alter the speed by varying the delay
between the step pulses.
Cheers
Geoff in Oz
> Indeed. I am in the process of making a pc
controlled pan/tilt head for
a
webcam using
bits gleaned entirely from 5.25" drives.
Indeed. All the more reason that old computers shouldn't just be treated
as scrap metal. There are useful parts in there. > By using the stepper controller and some of the
sensors that already
exist
> in the disk electronics it can interface directly
to a parallel port
that I
This is quite easy to do on older drives, but more modern (particularly
3.5") ones have all sorts of 'interlocks'. The head moves back and forth
at power on to check the track 0 sensor is doing the right thing and so
on. If it doesn't then the drive won't respond to interface signals.
The older Chinons aren't too bad, though some of the control lines do not
function like the old tandons.
The NMOTORON which is supposed to toggle the spindle motor does nada, there
is a IR photo interrupter that
starts the motor when a disk is inserted. Can't get a pulse from Write
Protect or Track 0 at the interface, though oddball things happen if I
remove the sensors. Got around NMOTORON by removing the IR PI and tieing
the line to the pin on the port directly. The Track 0 sensor upsets the
stepper if you remove it, basically makes it stop after a half turn. Using
the WP sensor which seems to work with visible (fluoro) or the IR led
source, to pull down an input on the port, though still tinkering with
getting the computer to recognise the toggled bit. Using the input side,
(Hex 0379) but getting no response, possibly the cheapskate port on the
diskless box is not bidirectional, so might try the status register instead.
So you may not be able to use much of the control
electronics. It depends
on the drive. If there's a microcontroller surrounded by buffer chips
(say mid 1980's designs) then you can probably make use of (at least) the
buffers and surrounding components. If there's on ASIC then the control
board may not be much use to you.
Yes, I have taken apart a 3.5" drive that does a head seek and stops. The
method I'm using with the chinons is to leave any sensors that cause trouble
where they are, and tie others directly to the proper pins.
> control with software written in my (classic?
must be close.) 'old but
good'
Turbo Pascal 6
for DOS.
I think it is a classic. I got my first PC in 1991 (a true-blue XT that's
still in use). I am pretty sure TP v 6 was available then. > By judicious use of the drive select lines,
it's possible to control
several
> 'drives' from the one port so a pan and
tilt plus (say) focus or
something
Let's see. You need step and direction. 2 signals. Maybe a 'track 0'
(home position) sensor input to the PC (you can feed that in on the busy
line or something).
Yup.
That's 2 bits, so you could use the other 6 data
lines to select 6 'drives' with no extra electronics. Add a couple of TTL
chips ('138s are useful) and you could go beyond that.
yep no big deal at all. Numerous possibilities.
> similar is possible. Got plenty of half dead
5" drives, prefer the
older
> Chinons as they have huskier stepper motors with
conventional shafts,
the
I'd probably go for the old Tandons (mainly because I have a box of dead
ones...).
I'm looking but yet to find any, they are far easier to interface to.
Nice big stepper motors, the electronics is all simple
TTL, etc
(so there are no 'features' that prevent you using just the stepper
drivers),
Yes exactly.
and the schematics are easy to get.
Oh? Now that would be a help, where from?
Obviously I prefer to repair such drives when possible
(I do still _use_
5.25" disks here),
Me too, but have plenty of spares that are beaten up, broken heads etc.
One of my printers (a Sanders 12/7) has a stepper
motor to drive the
platten (direct drive -- the platten is roll-pinned to the motor shaft)
and another one in the optional tractor feed unit. Both are wired in
parallel to the same driver circuit If you turn the tractors with the
machine switched off, the stepper motor generates enough voltage to deive
the platten motor
yeah sounds like a relative. Big sucker.
> it I can get better than 1 degree resolution.
Will need to build an
> appropriate driver board, it would toast a floppy drive stepper
controller.
Did you save any of the printer's electronics? At least the output stages
should be useable.
Got the entire board. Including all the pin and stepper drive transistors
and the psu.
(Print head was stuffed in it)
> from the 60w psu. Powering it from a separate
supply creates earth
looping
issues that
confuse the hell out of the logic by lifting the pulled down
You have linked the -ve rail of your external PSU to the ground on the
computer's parallel port I hope...
17 Feb
17 Feb
9:03 a.m.
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12:18 p.m.
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Monday, February 18, 2002 6:33 AM
Subject: Re: Destructive charities (was: STAPLES STORES...)
Of course. I've got plenty of PCBs where one custom chip has failed. I
keep them as a source of the _other_ custom chips on them, for example.
Precisely.
At the risk of being flamed, original PCs and PC/XTs use them. As do many
CP/M machines. Oh, and TRS80 Model 3 and 4. No, I am not suggesting
raiding such machines just for the drives, but the drives can't be that
rare...
Hmm, not many of either around here. I have a genuine XT and a TRS80 Mod 3?
4? but I don't
want the drive that bad.....
Did think of that, but I would prefer to have direct control over the motor,
as I think the onboard firmware will cause
undesirable effects. Realistically, the psu and driver transistors should
be all I need. I'll generate the step sequences in software, since I want
to be able to half step if necessary.
> > Indeed. All the more reason that old
computers shouldn't just be
treated
as scrap metal. There are useful parts in there.
Yes, either for experimentation/reuse or to fix other machines. > > I'd probably go for the old Tandons
(mainly because I have a box of
dead
ones...).
I'm looking but yet to find any, they are far easier to interface to. IBM Options and Adapters TechRef, TRS-80 Model 3
service manual. To name
but 2 manuals I have that contain said schematics. I guess there would
have been an official Tandon service manual, but I've not seen it (yet).
Hmm, ok, thanks, I'll look into that.
> > Did you save any of the printer's
electronics? At least the output
stages
> > should be useable.
>
> Got the entire board. Including all the pin and stepper drive
transistors
In which case it wasn't a Sanders 12/7. That's on 4 or 4 plug-in boards
inside. And a separate SMPSU.
No, a very old Citoh IIRC. Came from a bakery, it's about 18" high and
weighs a ton.
and the psu.
(Print head was stuffed in it)
Depending on the space you have available, you might be able to use the
printer PCB as-is. Just send it space and CR characters :-). And you're still getting 0.4V between the computer
ground and the
peripheral ground??? How much current is flowing in that ground
connection?
Miniscule, around 5ma. Just enough to be a PITA.
I'd use an external PSU to power the 'disk
drive', wired up to the 4 pin
power connector only. Then link the ground pins on the drive interface
connector to the ground on the computer's parallel port. What happens now?
Same story. .4v potential difference between the grounds. This should not
be so under this circumstance, so I am suspicious of the board.
Cheers
Geoff
8187
days inactive
8190
days old
11 comments
8 participants
participants (8)
-
ard＠p850ug1.demon.co.uk -
doc＠mdrconsult.com -
edick＠idcomm.com -
fernande＠internet1.net -
geoffrob＠stmarks.pp.catholic.edu.au -
lgwalker＠mts.net -
mythtech＠Mac.com -
rdd＠rddavis.org