hi there!

well the pdp was once a pdp 11/23+ so
enclosure and backplane should be
the same as a 11/23 (ba 23). backplane should
be Q22/CD configuration, but
i´ll open the box and look for the 501-
number to be sure. on the back there
is a sticker saying this is a 11/73. the
cpu-board is a 11/83.(i´ll pass
the number too). do all 11/83 use PMI ? but
the memory seems to work, or has
the cpu board some memory on it?
when i picked up the box they booted it, i
suppose this configuration was the
way they used it there and should have
worked.
the RD54 controller has a 50pin ribboncable
wich goes to a small board (wich
was hanging on the backside) and a small
frontpanel (from a 11/83 or 73) was
hanging on it. it looks like

*************
*     *'''''*    O is a round hole (to hold a
batch?)
*  O  *'''''*    '' is a big hole (power
switch i suppose)
*     *'''''*
*************
*  X     B  *    X = run on/off ?(green led)
B = reset ?
*  X     X  *    X = write protect(red led) X
= online(green led)    for disk 0 ?
*  X     X  *    X = write protect(red led) X
= online(green led)    for disk 1 ?
*************
X is a switch with led B is a button with led
i never saw a pdp with this frontpanel, and
since there is nothing written on it,
i tried to compare with a picture found on
the web, but i´m not sure if i´m right.
can someone tell me if i´m right ?
i asked those guys from where i picked up the
box, but they told me that the last guy
using the pdp left some years ago, and in
1999 they just powered it off. this explains
also the small paper sticking on the pdp that
showed how to login and shutdown the box.
root password is written on it *g*.

tomorrow i´ll open the box again.

thanks for your fast response.

-- lothar


FWIW, I don't know about the tape error, but
that layout looks OK apart
>from the fact that if it's an 11/83, the
memory shold be in the first slot
and the CPU in the second.  The essential
difference between an 11/73 and
an 11/83 is that the 11/83 uses PMI memory.
Assuming your backplane is the
right one, in a BA23 or BA123 box, and that
your memory is a single 4MB
board, you should swap them round, otherwise
what you actually have is an
11/73.

I assume your RD54 controller is a genuine
DEC RQDX3, so it's in the right
place.  It's possible you have an old version
of the firmware on it, but it
should still work even if you do.

all the planes in the backplane are genuine
dec parts.

--
Pete

What enclosure? BA23? If yes you have empty
slots between the cards as
this box has 3 Q/CD slots on top and 5 Q/Q
slots below. Have a look at
the QBus HOWTO at
http://vaxarchive.sevensages.org/
--

tschuess,
          Jochen