Ok, got a bit of time yesterday and today to clean up the work area so I
could work on the /45, and to actually go through some of the tests Tony had
suggested. First, let me describe the current setup, as I changed things
around a bit in order to simplify the setup. Here is how the machine is
configured right now, and how it was configured during the following tests.
I did not leave out any cards in my list here, so if you don't see it
listed, there isn't anything in that slot.
Current configuration
System Unit
1 (A-B) M930C
2-5 empty
6 (A-F) M8100
7 (A-F) M8101
8 (A-F) M8102
9 (A-F) M8103
10 (A-F) M8104
11 (A-F) M8105
12 (A-F) M8106
13 empty
14 (A-F) M8116
15 (C-F) M8109
16-25 empty
26 (A-B) M9200 side 1 (C-F) M7856 {note, the LTC option on this board is
enabled, there is nothing in slot 1C}
27 (A-B) M9200 side 2 (C-D) Dual Grant
28 (A-B) BC11A-0F side 1 (C-D) Dual Grant
MF11-L in system unit
1 (A-B) BC11A-0F side 2 (C-F) H214
2 (A-F) G231
3 (A-F) G110
4 (A-F) G231
5 (A-F) G110
6 (C-F) H214
7-8 empty
9 (A-B) BC11A-15 side 1
BA11-KU with DD11-DK
1 (A-B) BC11A-15 (C-D) Dual Grant
2 (A-F) M7762
3-7 (C-D) Dual Grant
8 (D) single grant
9 (A-B) M9312 (D) single grant
Connected to the M7762 is an RL02, and connected to the M7856 is an ADDS
vt100 clone. Before I go further, I should point out that the system DOES
have some basic functionality. It CAN boot up xxdp, and does pass a few
front panel tests. The basic problem is I suspect that interrupts aren't
working right. I suspect this because when trying to boot a known good RT11
pack, it hits the disk for at least 30 seconds before halting, and it's
definitely progressing and not just retrying one read over and over. Many
diagnostics fail, but they seem to fail whenever something with interrupts
is being tested. Let me also say I'm new to the /45, but learning, so I'm
not entirely 100% sure I'm operating the front panel right. In other words,
it is very possible this is all due to some stupidity on my part!
No, I think it's a real fault, not operator error.
[XXDP+ output snipped]
At this point, nothing else is displayed. The above
output makes perfect
sense to me, with one exception. What on earth does it think when it shows a
DP11 sync interface at 774400? Um, that address is what my RL11 is set to.
Probably becuase the initial use of that address was for a DP11. It finds
_something_ there and assumes it's a DP11.
Not sure why it shows as a DP11, maybe that's a
bug in this sizer program.
In any case...
First, Tony suggested I store sucessive bits and read them back, ie. start
at loc 0 and store 0,1,2,4,8 etc. I did that. All stored and read back
correctly.
OK, you don't have a data bus error (the fact it'll boot XXDP+ would
confirm this too).
Then Tony suggested that I run instruction diagnostics. I did that, and
below is the output.
-----------------------------
022700 000012 001000 000020
@DL
CHMDLE0 XXDP+ DL MONITOR
BOOTED VIA UNIT 0
16K UNIBUS SYSTEM
ENTER DATE (DD-MMM-YY):
RESTART ADDR: 072010
THIS IS XXDP+. TYPE "H" OR "H/L" FOR HELP.
.R CQKC??
CQKCG1.BIC
DCQKC-G 11/40 & 11/45 INST EXER
OPT.CP=045406
OPT.DEV.=000001
PASS #0000 VPC=072452 PSW=000344
PASS #0000 VPC=072452 PSW=010344
PASS #0000 VPC=072452 PSW=010344
PASS #0000 VPC=072452 PSW=010344
PASS #0000 VPC=
----------------------------
On the above diagnostic output, the system prints up to and including
"OPT.DEV.=000001" very quickly, then runs for a long time (maybe 2 minutes
or more), and then prints out the 5 lines of "PASS..." all very quickly. The
cursor just sits to the right of VPC= on the last line, forever and the
processor is halted. I'm betting money this is a bad result from this
diagnostic. No clue what it means. But.... read on....
I wonder if it's tried an illegal instruction trap, or an EMT trap, or
something , and it's failing on those too.
Now, I entered the above program. When I run it, it
halts with PC = 4, NOT
104 and the data display shows 000770. Yes, I'm sure there are no burned out
front panel lights. To my limited knowledge, this sounds like the program
got the interrupt but instead of jumping to 100 for the vector, it jumped
somewhere around 0 or 2, since the PC said 4. The plot thickens though, read
I think it tried to load the vector from location 0. got a '2' from there
into the PC, jumped to location 2, which contains a halt instruction,
halted there, so the PC contains 4 (address of next instruction so you
can CONTinue).
on....
I took the above program and modified it to set bit six of the receive CSW
to 1 (receive character interrupt enable) on the SLU, I believe I did it
correctly by just changing location 1032 to 177560. When I run this program,
the system is looping at 1034 just like it should... until I hit a key on
the console. The moment I hit a key on the console, the processor halts with
PC=4, and the data display shows 000770. So it seems that whether the
interrupt comes from the LTC or the SLU, no matter what it halts at loc 4
Right. What this suggests to me is that yet again it fetched the vector
from location 0, etc. In other words, the processor
ignores the contents
of the data bus at this time (the data lines are driven by the
interrupting device, and should give the address of the vector to be
used).
[RL test output]
ILL INTER 000
PC 013634 PS 000004
That sounds suspiciously like 'illegal interrupt to location 0' :-)
----------------------------------
If I'm understanding what I'm seeing, it seems the processor is ignoring all
vectors as Tony suggested. Of course, I am not skilled enough to know where
Right, that's what I think too.
to go from here. I can say that my processor cards
(M8101 through M8106)
were borrowed from another collector and tested before I got them, but I
I think the problem is on one of the processor cards. To find it is going
to involve diging into the logic -- do you have the necessary test gear
(logic probe, 'scope, etc)? Do you feel happy getting amongst a machine
with over 1000 ICs in it (yes, I know the feeling. That's how I felt when
I got my 11/45. I spent weeks just reading the printset).
If you do want to go ahead with this (and I think you should!), I'll get
out the prints and the technical manual and go through it with you. That
is, unless I get flamage for not providing scans of these manuals.
-tony