30 Jul
2016
30 Jul
'16
1:06 a.m.
Sometimes you are lucky... A friend got a lot of documentation in a haul
just a few days ago, among it was some documentation about NORD-1 and
the ExpandaCore-18 was among it. So now I have complete schematics and
even some timing diagrams. :-)
For reference I'll include the link to the document page,
https://sites.google.com/site/tingox/nd_documentation
Just in case someone would be looking for this document in the future
and finds this post.
He also had a lot of other good stuff for me but not scanned yet, I'll
just have to wait for that. Realistically I don't think I'm ready to add
a hard drive to the machine yet as I'm not sure I can even read the
memory. :-D
G?ran
Den 2016-07-26 kl. 01:15, skrev G?ran Axelsson:
Den 2016-07-25 kl. 14:37, skrev Camiel Vanderhoeven:
Op 25 jul. 2016 2:25 p.m. schreef "G?ran
Axelsson"
<axelsson at acc.umu.se>:
Thanks for the answer.
The ExpandaCore 18 (tm) ;-) is a unit with the driver electronics and
core memory together. One control board per four memory planes and
dual ported so a high speed device could write straight into the core
memory without going through the CPU. In my case it seems like I have
a packet drive interface that uses the second channel.
I have put up some more pictures here :
http://www.home.neab.net/gandalf/ClassicComputing/Pictures/Nord-1%20%2347/
Maybe I'm jumping to conclusions here but there is one "control board"
for each four core planes. Maybe it's just a buffer. A problem with
the core memories is that it sits tight in a crate and I have no
extender for these cards. At least I should be able to measure the
signals from the CPU to the control board, and from the control board
to the memory planes.
My guess so far is that there is a problem with
reading and writing to
the memory. The problem is that I have no documentation over
the memory
module except a drawing of the circuitry used to access it. ND bought
several different models of core memory for it's early computers and
just
adapted the interface.
So once again I turn to the cctech for help, does
anybody have
instructions about ExpandaCore 18 from by Cambridge Memories INC,
Newton,
Massachusetts (also known as CMI but probably not the CMI on bitsavers).
So far the only thing I've found was a
newsflash in a computer magazine
about a sale of memories to another computer
maker.
I can't help you with that, but is it just the core stack itself you
don't
have docs for, or does the CMI part include some driver circuitry? If
it's
just the stack, you should be able to do without docs for that. Core
memory
doesn't go bad unless it's physically damaged. If it is physically
damaged,
repair can be very difficult, depending on the diameter of the cores. How are you troubleshooting this? Can you deposit
a value in memory from
the front panel, then read it back? If that works, but one or more
bits are
off, there's a good reason to look at the core driver circuitry. If it
doesn't work at all, the problem could be anywhere. Try hooking a logic
analyzer to the address and data lines, clock, and read/write control
lines
for a start.
Good luck!
Camiel
I can deposit a value in the address register (R) but that is as far
as I have come right now. I can also look at the other registers. I
think that the memory content should show up when I enter an address
but I get back the same value as I entered.
The operators panel is a bit broken down, there are a couple of bad
switches but new ones is in the mail. Some keys react on vibrations.
At the moment I can't do any measurements on the CPU-cards as there
are no space in that crowded rack. But yesterday I cadded an extender
for the NORD-1 CPU crate so in a week I'll be able to do some
measurements on that part at least.
I got a cheap USB-connected logic analyzer and a digital sampling
oscilloscope, so with the extender cards I will be able to measure or
break up and inject any signal I want in the CPU.
This is too fun to be healthy! :-)
G?ran