General Question about UNIBUS backplanes

william degnan billdegnan at
Tue May 24 10:03:10 CDT 2016

> What never was clear to me was if you actually could access the serial card
> or not from the console. I.e. did it respond when addressing it? If it did
> respond I would check that there were correct power supplied to the 1488
> driver.
> /Mattis
The M9312 does yes  have the terminators installed.

I have not been able to activate the M9312 with the DD11C backplane
"behind" the newly-installed core and DD11B backplanes.  I don't know if I
fried it somehow recently.  It was working before.   The M9312 is installed
on the 4th slot in the DD11C with a NPG card below it.  It is also possible
that instead I am not communicating with the cards in the back of the bus.

Typically I toggle and run from address 165144 from the front panel, then
use the console program from a terminal to go from there.  Since my recent
shenanigans with the backplanes the console program does not appear to load
nor run.

When I load the address 165144 I see the correct address on the front
panel.  RUN BUS PROC CONSOLE are all lit.  When I enable and start the
system the address lights go out except 020 (2nd to last light).  The RUN

When I examine
165144 177570
165146 177570
165150 177570
165152 177570

I don't know the status of my M7856 card.  There are things I can try but
first I believe I should test to see if I am "pinging" to the DD11C at
all.  I also need to check power output levels and adjust.

I am thinking also test the MOS RAM from the DD11C by itself to see what
that tells me.  I know to address the RAM somewhere other than the 16K
space from 000.


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