On Aug 27, 2015, at 7:13 PM, Michael Thompson michael.99.thomp...@gmail.com
wrote:
...
In any case, RP06s use three phase power. The issue wasn't the power in
this particular story, but rather the ground wire (the green protective
ground that isn't supposed to carry current at all under
On 2015-08-28 14:56, Paul Koning wrote:
On Aug 27, 2015, at 7:13 PM, Michael Thompson michael.99.thomp...@gmail.com
wrote:
...
In any case, RP06s use three phase power. The issue wasn't the power in
this particular story, but rather the ground wire (the green protective
ground that isn't
On Fri, Aug 28, 2015 at 6:56 AM, Paul Koning paulkon...@comcast.net wrote:
That's interesting. I was told that an RP06 requires attention to the
correct phase connections or it will attempt to spin in the wrong direction,
implying that it uses a 3 phase spindle motor. Or perhaps that was a
Paul Koning wrote:
I can't vouch for the truth of the story; I heard it a long time ago from a
fairly reliable source.
The story seems plausable but I disagree with the theory of how it could have
happened.
But consider this theory. Suppose you have two service drops, fed from
On Aug 26, 2015, at 3:16 PM, Jay Jaeger cu...@charter.net wrote:
On 8/26/2015 8:19 AM, Paul Koning wrote:
I heard of this sort of thing happening to the DEC building at Marlboro.
Supposedly it had two mains entrances, served from different power lines
(and different companies? Seems
On 8/22/2015 4:11 PM, Eric Smith wrote:
In my mostly misspent youth, I once had the opportunity to visit a
facility where a now obscure supercomputer was developed. The product
manager was showing me around.
Denelcor perhaps?
On 2015-Aug-26, at 12:13 PM, Jay Jaeger wrote:
Also, when I was a kid, I was playing around with a Jacob's Ladder I had
made using a old vibrator-equipped Ford spark coil (I may still have
that around), and I had a telegraph key as a switch. Welll, one day I
was adjusting the ladder
From: Paul Koning
What happened is that the grounds were offset enough, and with enough
of a current supply, that the ground strap that's supposed to connect
the row of RP06 drives melted.
This sort of thing is a major electric code violation: you can certainly
have
On 8/26/2015 8:19 AM, Paul Koning wrote:
I heard of this sort of thing happening to the DEC building at Marlboro.
Supposedly it had two mains entrances, served from different power lines (and
different companies? Seems odd). One of the machine rooms had feeds from
both ends, and one
On 8/26/2015 1:20 AM, jwsmobile wrote:
Microdata card extractors were always engaged to a rail that was metal,
and in one site I was at, there was a CE sized hole in the wall behind a
system when the engineer extracted the printer card and the card
extractors came free from the system.
Yup, in the first house I owned, i had a computer room.
Whereas now you have a 'computer house' ?
The previous owner had done some retrofits and installed an
outlet in a closet. I plugged a printer into that outlet,
and my computer (S-100, CP/M) into another on the opposite
wall. Some
On 08/26/2015 08:19 AM, Paul Koning wrote:
Turned out there was a 120v potential between the dedicated power for the
computer and the printer which was plugged into the normal building power.
There was probably as much as an amp going thru the grounds from the terminals
in the building and
.
Regards,
Andrew Burton
aliensrcoo...@yahoo.co.uk
www.aliensrcooluk.com
- Original Message -
From: drlegendre . drlegen...@gmail.com
To: General Discussion: On-Topic and Off-Topic Posts
cctalk@classiccmp.org
Sent: Tuesday, August 25, 2015 11:51 PM
Subject: Re: A tale of woe, including
On Aug 26, 2015, at 4:07 PM, Noel Chiappa j...@mercury.lcs.mit.edu wrote:
From: Paul Koning
What happened is that the grounds were offset enough, and with enough
of a current supply, that the ground strap that's supposed to connect
the row of RP06 drives melted.
This sort of thing is a
On 8/26/2015 2:33 PM, Paul Koning wrote:
On Aug 26, 2015, at 3:16 PM, Jay Jaeger cu...@charter.net wrote:
On 8/26/2015 8:19 AM, Paul Koning wrote:
I heard of this sort of thing happening to the DEC building at Marlboro.
Supposedly it had two mains entrances, served from different power
On 8/26/15 12:33, Paul Koning wrote:
90? Three phase power is 120 degrees apart, center-tapped two
phase home power is 180 degrees, but I don't know of any power
company service that produces 90 degree shifts.
There's a bunch of 90-degree two-phase stuff in Philadelphia; in
particular the
On 08/26/2015 12:02 PM, tony duell wrote:
Yup, in the first house I owned, i had a computer room.
Whereas now you have a 'computer house' ?
The previous owner had done some retrofits and installed an
outlet in a closet. I plugged a printer into that outlet,
and my computer (S-100, CP/M)
On 8/26/2015 3:07 PM, Noel Chiappa wrote:
From: Paul Koning
What happened is that the grounds were offset enough, and with enough
of a current supply, that the ground strap that's supposed to connect
the row of RP06 drives melted.
This sort of thing is a major
Remember that most injuries associated with electric shock are secondary -
that is, the real damage often occurs when the individual recoils from the
shock, jamming their hands into even worse places in the equipment - like
rotating assemblies. And then there's the innocent guy behind you, who
As a child I remember getting a shock from a fridge and being thrown
across the room into the wall opposite. I really did crash into the
wall quite hard, so I can imagine it being very easy for the shock to
cause other injuries.
Regards
Rob
On 26/08/2015, tony duell a...@p850ug1.demon.co.uk
On Sat, Aug 22, 2015 at 3:35 PM, Jay Jaeger cu...@charter.net wrote:
On 8/22/2015 4:11 PM, Eric Smith wrote:
In my mostly misspent youth, I once had the opportunity to visit a
facility where a now obscure supercomputer was developed. The product
manager was showing me around.
That
Whether low-impedance voltage sources are present, or not, you should
+never+ wear any kind of hand / wrist jewelry when working with moving
parts. Ditto for neck chains and long hair, that isn't securely tied back.
Seems like First Grade instruction for the tech, but accidents still
happen..
On 8/22/2015 4:11 PM, Eric Smith wrote:
In my mostly misspent youth, I once had the opportunity to visit a
facility where a now obscure supercomputer was developed. The product
manager was showing me around.
That wasn't Astronautics' ZS, by any chance? I ask, because I know some
folks
On 8/22/2015 12:55 PM, Tapley, Mark wrote:
Jay,
this is a really great post. I feel really bad for you - having the
same piece of equipment go bang/flash more than once would have been totally
demoralizing to me - but I really admire both your tenacity and your
willingness to share
On Sat, Aug 22, 2015 at 1:41 PM, Jay Jaeger cu...@charter.net wrote:
But the carelessness was DANGEROUS, which is really why I posted it.
(BTW, in the way of other stories, a good friend once took out the
processor UNIBUS interface and damaged peripherals when his watch
shorted to the
On 08/22/2015 02:41 PM, Jay Jaeger wrote:
Thanks. Really, such mistakes aren't too demoralizing if
one can get the parts, get them in a reasonable amount of
time, at a reasonable price, and have the skill to do the fix
One of the biggest oopses I ever had was I got a Memorex 10
MB hard drive
The engineer said that it wasn't a problem because the highest voltage
on the backplane is 5V. The manager pointed out that the power supply
was rated for 600A, and undoubtedly could source more than that
briefly, and to think about what would happen to your finger if you
had hundreds of
Jay,
this is a really great post. I feel really bad for you - having the
same piece of equipment go bang/flash more than once would have been totally
demoralizing to me - but I really admire both your tenacity and your
willingness to share this with the rest of us.
Thank you!
What follows is a tale of carelessness, stupidity and laziness. So far,
I haven't found an excuse to add ignorance to the list. ;) As you may
recall, I was testing an 8 floppy drive that was reading inconsistently
on an Altos 8000 system, when, while testing with a replacement drive,
the 24V
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