H750 (PDP-11) power on?

From: Tom Uban <uban_at_ubanproductions.com>
Date: Thu May 27 10:03:40 2004

>Power controller? Same as a power supply?

A power controller is another box which typically plugs into
the main power source and has a number of switched and un-switched
outlets. It also has some of those 3-pin connectors on it, usually
one "in" and two "out", as well as a local/remote switch and circuit
breaker. The power controller allows the connection of the 3-pin
on the back of the CPU box to control the power of the entire rack
of equipment at the turn of the key switch on the CPU.

If you are talking about just your 11/10 box, then you don't need
to worry about a power controller.

>This one has the PSU on the right side with no obvious
>switches that I've yet found (maybe I have to change my
>definition of obvious).
>Breaker as I said is a just a small button, or,
>it's hidden under a cover somewhere... more looking.

Yes, this is just like my 11/05. There are likely to be fuses inside
of the power supply as well, but you will need to consult the manual
I pointed you at yesterday on this point.

The key switch on the front of the CPU has 3 positions, OFF, POWER,
and PANEL LOCK. Both POWER and PANEL LOCK should turn on the power
supply, but the console switches will be disabled when in the PANEL
LOCK position.

> > On the power controller there should be a little toggle
> > switch. This should be set to 'Remote'.
>
>Not found (yet). This is one of the oldest PDP's made.
>Second model, I believe.

The 'Remote' switch refers to the power controller which I described
above. There isn't a 'Remote' switch on the 11/10 CPU itself.

> > Try connecting the CPU mains cable directly to the mains
> >(without the power controller)...
>
>CPU mains cable sounds obvious, but what I have may be
>the power controller cable(?)
>Like I said, please define it for me.

The term "mains" is European for A/C power cord.

>Yes, I just looked around again with a flashlight, and peering under
>the varouus grillworks, stopping just short of removing the PSU cover.
>No circuitbreaker-switch. The two three pin ports that I mentioned first
>up are located directly in front of a fair sized relay. Will try switching
>there (and in front with the microswitches) at next opportunity, in a few
>hours.

The two 3-pin connectors would normally run to the power controller (described
above) and allow the CPU key switch to turn on/off the power controller's
switched outlets, thus controlling the power of the other devices in the
rack(s).

You need to look in the schematics at the H750 and console panel drawings
and figure out how to bypass your key switch, or get yourself a key. If it
is the same basic (flat, not cylindrical) key that my 11/05 uses, I could
have it copied for you. I also have the standard DEC cylinder key, which I
can also have copied for you if you need.

http://bitsavers.org/pdf/dec/pdp11/1105S_Schem.pdf

--tom
Received on Thu May 27 2004 - 10:03:40 BST

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