3 Jan
2006
3 Jan
'06
4:01 p.m.
Greetings to all, and here's to 2006!
My first post, though I have skulked for months...still, consider me a
PDP newbie...
I've recently acquired a fully functional PDP-11/23plus with the idea
that I'd re-acquaint myself with RSTS/E which happened to be the first
system I was actually paid to program on. Trouble is, it was a short
stint with this local VAR, and it was nearly 30 years ago! I don't even
remember what the systems were exactly, though I think they were
11/40s. Stangely, these systems were in blue cabinets (did DEC ever do
blue?), with none of the typical maroon or red PDP-11 signature
color...that is until the LSI models started showing up in white, which
is what I've got.
Anyway, I'm now happily in the process of re-assembling the system and
preparing for my first power up since getting it home. The
configuration I have is in a double-wide 40" tall rack unit. Each rack
or 'bay' between the three uprights has a 874-A power conditioner /
power-strip unit that I'm trying to understand. I haven't been able to
find any references to this component. Though I could just replicate
the configuration that it had before being relocated (switches, wiring,
etc.), which I have plenty of photos of, I'd like to understand this
compenent better.
Since I have a double-wide cabinet, I've got two of these units that are
linked together with a 3-conductor cable, each end plugged into one of
the four "Power Control Bus"-labeled sockets. One 874-A also has
another connection from a second "PCB" socket to the the 11/23+
processor box. My guess is this line somehow is controlled by the front
panel AUX ON/OFF switch.
Also, each of the 874-A units has a small 3-position toggle switch:
'Remote On', 'Off', and 'Local On'. Before I go much further with
experimenting on my own, I wonder if anyone here knows these units and
can offer some info about how these units tie together and what settings
do what. Comments?
J.
3 Jan
3 Jan
5:16 p.m.
or 'bay' between the three uprights has a
874-A power conditioner /
power-strip unit that I'm trying to understand. I haven't been able to
find any references to this component. Though I could just replicate
the configuration that it had before being relocated (switches, wiring,
etc.), which I have plenty of photos of, I'd like to understand this
compenent better.
Since I have a double-wide cabinet, I've got two of these units that are
linked together with a 3-conductor cable, each end plugged into one of
the four "Power Control Bus"-labeled sockets. One 874-A also has
another connection from a second "PCB" socket to the the 11/23+
processor box. My guess is this line somehow is controlled by the front
panel AUX ON/OFF switch.
Also, each of the 874-A units has a small 3-position toggle switch:
'Remote On', 'Off', and 'Local On'. Before I go much further
with
experimenting on my own, I wonder if anyone here knows these units and
can offer some info about how these units tie together and what settings
do what. Comments?
All thse DEC power controllers are basically the same, although the
internal circuitry differs somwahat.
They contain a large relay (contactor) that controls the mains to the
switched socket outputes on the unit. This is controlled by some
simple-ish electronics in the unit (IIRC, the 861 controller used a
differentially-wound reed relay!) Anyway, the 3 positions of the toggle
switch mean
Off : The contactor is always off, no matter what happens on the power
control bus
Local On : The contactor pulls in, it can be turned off by the shutdown
line on the power control bus, though.
Remote On : The contactor is controlled by the power control bus
The 3 wires in the power control bus are : Ground, Ground-for-on (which
is how you turn on the contactor in the Remote-On mode), and
Ground-for-off (which is a shutdown line that will turn off the contactor
no matter what it telling it to be on). There is no latching associated
with this, toy can control the contactor using the ground-for-on line only.
Typically, overheating-detection thermoswitches are connected between the
ground wire and the ground-for-off wire. If any part of the machine
overheats, the power controllers turn off the power to everything.
The frontpanel switch is wired between the ground and ground-for-on
wires. Thus the frontpanel switch can be used to turn on (and turn off)
the contactors in all the power controllers in the machine. I would guess
(without seeing you system) that the 3 pin socket on the CPU box is wired
so that you just plug the power control bus cable in there and it will
connect the switch contacts between ground and ground-for-on.
-tony
6:29 p.m.
In article <m1EtxG2-000IyPC at p850ug1>,
ard at p850ug1.demon.co.uk (Tony Duell) writes:
The frontpanel switch is wired between the ground and
ground-for-on
wires. Thus the frontpanel switch can be used to turn on (and turn off)
the contactors in all the power controllers in the machine. I would guess
(without seeing you system) that the 3 pin socket on the CPU box is wired
so that you just plug the power control bus cable in there and it will
connect the switch contacts between ground and ground-for-on.
Hey! This is sounding familiar! My 11/03 has an 861 power controller
on it and I have the three-position toggle switch as well. Thanks for
explaining what those settings are! I had no idea what this meant
when I first got the machine, but I had the switch set to "local on"
and then the unit would power up.
However, this idea that there's a way to powerup from the front panel
on an 11/03 intrigues me! Unfortunately I see no obvious button that
powers up the machine. Is this possible with an 861 and if there is
not existing switch, what would you add to enable this feature?
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
6:40 p.m.
AFAIK, there's only one panel for all 11/03, /23, and /23+ models, they just
come with different badges. You need a DEC power bus cable. Run it from
the connector on the CPU box to the power controller, set it to "remote on",
and flip the far right switch. Viola, power from the front panel.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Richard
Sent: Tuesday, January 03, 2006 8:29 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: DEC 874-A Power Conditioner
In article <m1EtxG2-000IyPC at p850ug1>,
ard at p850ug1.demon.co.uk (Tony Duell) writes:
The frontpanel switch is wired between the ground
and ground-for-on
wires. Thus the frontpanel switch can be used to turn on (and turn off)
the contactors in all the power controllers in the machine. I would
guess
(without seeing you system) that the 3 pin socket
on the CPU box is
wired
so that you just plug the power control bus cable
in there and it will
connect the switch contacts between ground and ground-for-on.
Hey! This is sounding familiar! My 11/03 has an 861 power controller
on it and I have the three-position toggle switch as well. Thanks for
explaining what those settings are! I had no idea what this meant
when I first got the machine, but I had the switch set to "local on"
and then the unit would power up.
However, this idea that there's a way to powerup from the front panel
on an 11/03 intrigues me! Unfortunately I see no obvious button that
powers up the machine. Is this possible with an 861 and if there is
not existing switch, what would you add to enable this feature?
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
4 Jan
4 Jan
4:30 p.m.
However, this idea that there's a way to powerup
from the front panel
on an 11/03 intrigues me! Unfortunately I see no obvious button that
powers up the machine. Is this possible with an 861 and if there is
not existing switch, what would you add to enable this feature?
It is certainly possible to do this with an 861 (I have an 861 in one of
the cabinets of my 11/45 system, it works with the other assorted power
controllers, all of which fire up whrn I turn the front panel key).
Near that toggle switch are some 3 pin connectors (I think a total of 3
of them). They are all equivalent, you can use any one of them. Shorting
the right pair of pins together with the switch in the Remote-On position
will turn everything on. You can find out which the right pins are from
the printset, or you can convince me to look in the printset.
Once you know that, you need to get a plug that will fit that socket.
It's a standard AMP Mate-N-Lock I think. Wire one end of a piece of (2
core) cable to the right pins on the connector. The other end of the
cable needs to go to suitable switch contacts. I am not sure if you have
a switch on the 11/03 box (it depends, probale, on the box, and anyway I
am not a Qbus person). If not, just use any on/off switch. The voltage is
around 24V, the current is well under 1A (and it's isolated from the
mains line), so just about any swtich would do.
-tony
3 Jan
3 Jan
5:35 p.m.
Welcome to the list!
The 874 is connected into the 11/23 box so that you can turn the system on
from the front panel. The idea is to flip the switch
on the 874 to "remote
on" (meaning from the front panel switch,
"local on" will turn everything on
regardless of the position of the front panel switch.)
What's in the rest of the cabinet? I'm curious about your configuration, as
I've built my own 11/23plus (two RL02s, SCSI, TK50, 9track, crystalfontz
display, dectalk, Ethernet).
Get in contact with me if you need some help getting RSTS/E set up. It can
be a pain if you've been rusty for awhile.
Julian
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of J. Blaser
Sent: Tuesday, January 03, 2006 6:02 PM
To: cctech at classiccmp.org
Subject: DEC 874-A Power Conditioner
Greetings to all, and here's to 2006!
My first post, though I have skulked for months...still, consider me a
PDP newbie...
I've recently acquired a fully functional PDP-11/23plus with the idea
that I'd re-acquaint myself with RSTS/E which happened to be the first
system I was actually paid to program on. Trouble is, it was a short
stint with this local VAR, and it was nearly 30 years ago! I don't even
remember what the systems were exactly, though I think they were
11/40s. Stangely, these systems were in blue cabinets (did DEC ever do
blue?), with none of the typical maroon or red PDP-11 signature
color...that is until the LSI models started showing up in white, which
is what I've got.
Anyway, I'm now happily in the process of re-assembling the system and
preparing for my first power up since getting it home. The
configuration I have is in a double-wide 40" tall rack unit. Each rack
or 'bay' between the three uprights has a 874-A power conditioner /
power-strip unit that I'm trying to understand. I haven't been able to
find any references to this component. Though I could just replicate
the configuration that it had before being relocated (switches, wiring,
etc.), which I have plenty of photos of, I'd like to understand this
compenent better.
Since I have a double-wide cabinet, I've got two of these units that are
linked together with a 3-conductor cable, each end plugged into one of
the four "Power Control Bus"-labeled sockets. One 874-A also has
another connection from a second "PCB" socket to the the 11/23+
processor box. My guess is this line somehow is controlled by the front
panel AUX ON/OFF switch.
Also, each of the 874-A units has a small 3-position toggle switch:
'Remote On', 'Off', and 'Local On'. Before I go much further
with
experimenting on my own, I wonder if anyone here knows these units and
can offer some info about how these units tie together and what settings
do what. Comments?
J.
6927
days inactive
6928
days old
5 comments
4 participants
participants (4)
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ard＠p850ug1.demon.co.uk -
fireflyst＠earthlink.net -
legalize＠xmission.com -
oldcpu＠rogerwilco.org