General Question about UNIBUS backplanes

[william degnan]

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> http://vintagecomputer.net/digital/pdp11-40/card-layout_moved-plane_Pic2.JPG
> > (I removed the grant cards from the core planes per Tony's suggestion.)
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> You don't have a terminator in the last slot of the bus. There should be a
> M930/M9301/M9312 installed there, not a RL11. It is possible to put the
> M9312 / M9301 there if you install the five jumpers (In my 11/10 there is a
> M9301-YF installed in a regular Unibus slot). With jumpers in the
> M9301/M9312 will terminate the BGx and NPG signals as well. Without jumpers
> these signals will be unterminated which is not good.
>
> Be careful to not put it into a MUD slot with the jumpers in, though.
>
> It is not clear to me if the DL11-W repsonds correctly when you try to
> address it or just doesn't output anything.
>
> Check grant continuity from last slot to the M981. But just to output a
> character on the console BG/NPG continuity wouldn't matter. Booting from
> the RL11 will not work unless the NPG chain (and BG chains are OK).
>
> I actually think that the reason for the RL11 not working is that the grant
> signals don't have a pull up anywhere in your config.
>
> /Mattis
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Thank you.  I can see that have corrections to make.  I need to continue my
studies of UNIBUS.  I have not been strict enough with set up.

I will verify that the M9312 is in the last slot and jumpered correctly.
Card slot 2 of the backplane was "de-jumpered" and requires a NPR card.
The RL02 needs to be in a slot that would otherwise need an NPR card, as I
understand things.  This slot *I think* is set so you can interchange NPR
and RL02 card.

I am going to start over from scratch, thanks everyone (Noel saw your post
too).  Stand by for "take two".

Bill