KDJ11-B PDP 11/73 getting stuck in Exit standalone mode diag #56

[Bill Gunshannon]

Can you post a description of this box again?  I had already deleted the earlier
parts of the conversation.  But it stuck in my mind.  I hmay have the book on 
this box as I think it is the same as the couple I have.

If so,  there were two versions of  the quad wide backplane.  One is A-B-A-B all the
way down.  And one is A-B-A-B except for slots 6-7 which have C-D for use with the
two board RL controller.

Please post brand name and any  model numbers yo have and I will dig thru my
library.

bill

________________________________________
From: cctalk [cctalk-bounces at classiccmp.org] on behalf of Noel Chiappa via cctalk [cctalk at classiccmp.org]
Sent: Tuesday, April 4, 2017 6:35 PM
To: cctalk at classiccmp.org
Cc: jnc at mercury.lcs.mit.edu
Subject: Re: KDJ11-B PDP 11/73 getting stuck in Exit standalone mode diag #56

    > From: Glen Slick

    > the Q22/Q22 backplane is not good for an 11/83 CPU ... M8190 boards and
    > both have PMI signals on the CD half of the CPU board.

So I seem to recall hearing tales of PMI cards emitting smoke when plugged
into a Q/Q/ backplane. That doesn't seem to have happened here:

     >> I confirmed the KDJ11-B works fine in a BA23, getting past test 56.

So I wondered if his off-brand backplane didn't have +12V or -12V wired up -
whatever it is that causes the damage. So I compared a list of PMI pins with
a QBUS pinout, trying to see if it was the +12V or 12V that would be the
problem.

However, I don't see any PMI pins that conflict? (Well, some of them are
ground, or +5V, but will that harm bus driver TTL?) Here's my list of PMI
pins:

  CB1   PSSEL
  CD1   PUBMEM
  CE1   PBCYC
  CF1   PUBSYS
  CH1   PHBPAR
  CJ1   PSBFUL
  CK1   PLBPAR
  CM1   PRDSTB
  CP1   PBLKM
  CR1   PBSY
  CV1   PUBTMO

  DB1   PWTSTB
  DC1   PBYT
  DD1   PMAPE

Anyone have any idea which pin(s) is the issue, when plugging a PMI card into
a Q/Q slot?

        Noel