Reanimating a PDP-11/23
pete at dunnington.plus.com
Mon Nov 30 16:34:04 CST 2009
On 30/11/2009 20:50, Pontus Pihlgren wrote:
> I've been trying to get my 11/23 back on its feet. I've tried the
> following setup:
> KDF11-AA (M8186, CPU)
> MSV11-DD (M8044-DD, Memory)
> DLVJ1-M (M8043, SLU)
> BDV11 (M8012)
> In both cases I see nothing on my terminal (I tried both a vt100 and
> vt320) were I think I should see the ODT @-prompt.
If you're using a DE-9 connector cable on a microPDP-11/23, or the cab
kit belonging to one, the pinout isn't the same as the common modern PC
version, as Ethan pointed out. If you're using a 25-pin D-connector on
some other cabinet kit, make sure you have Tx and Rx (pins 2 and 3) the
right way round, and signal ground (pin 7, not the same as protective
ground on pin 1) connected.
If you're using a 10-pin berg-style connector directly onto the DLV11-J,
check it's made up correctly; it has differential signals and you need
to link pins 7 and 9 to make it work properly (though I'd not expect
that to stop it transmitting. The other pins you need are Tx+ on pin 3,
Rx+ on 8 pin, and ground on pin 2.
Whatever you're doing, make sure you have the baud rate set correctly.
If the speed is wildly out, you may see nothing. If you have Tx and Rx
mixed up, you will see nothing. And on a DLV11-J, make sure you're
using the correct port -- only port 3 can be the console port (the one
on the extreme left as you look at it from the back) -- and that it is
actually set up as a console, and that the DLV11-J is set to the
standard address. You can set a DLV11-J *not* to reserve one port for
the console, and you can also set it to different start addresses
(though that shouldn't, in itself, affect the console port, if it's
configured to provide one).
Unlikely to be wrong, but do you have the cards in the right places in
the backplane? If this is a serpentine backplane, they should be in
slot 1 AB, then slot 1 CD, slot 2 CD. If it's a straight backplane
(standard for an 11/23) they should be one under the other, with no
cards in the CD section (except, of course, the BDV11 which take up all
4 sections of the slot).
> Also, the AUX on/off switch does not work, how is it connected to the
If this is a standard BA11-N or BA11-S box, or anything similar, that
switch isn't connected to the PSU, exactly. It is usually jumpered to
enable/disable the LTC signal, but it can be cabled to the rack's power
controller using a 3-core cable with a 3-pin AMP Commercial Mate-N-Lolk
connector on each end.
Pete Peter Turnbull
University of York
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