4 Oct
2015
4 Oct
'15
10:46 a.m.
I have spent some time on the ill PDP-11/10 this weekend.
I have this machine already a few years, but I recently got an empty
H960 rack, which would be the perfect home for this PDP-11/10.
When I picked up this 11/10, the story with it was "not good".
"We put the boards in the backplane and switched on the machine.
When we saw smoke, we turned it off. We did not know that the boards
had to go in specific slots ..."!
This machine is an 11/10"S" with 16KW core in the 9-slot CPU backplane.
So, possibly the +20V core supply voltage fried ICs. However, a visual
inspection did not show any blown ICs.
After removing all boards (stored in ESD-safe bags), I first checked
the power supply. All voltages are present on the backplanes. DC LO
and AC LO are at 4.6V and have a ripple of 130 mV.
Seems acceptable to me.
Next, I placed the two CPU boards in the backplane. Of course in the
correct slots :-) and connected the console ribbon cable. Power on...
The RUN LED stays on. Alas, it is not the infamous NPG problem. The
console is not responsive, although ENABLE/HALT and then START makes
DATA/ADRRS LED 0 go on. But that's all. Seems like some fault finding
is needed in the CPU and console.
I downloaded "DEC-11-H05AA-A-D_1105um.pdf". In the back are some tests
that you can do. I hope to find the problem by elimination. Chapter 6.11
describes a few useful checks to verify the console stand alone. Great!
All 8 tests check out just fine, but ... the data pattern on the LEDs
is "inverted"! The manual says for test numbers 5, 6, 7, and 8 that the
LED pattern must be 052525, 031463, 007417, and 0003777 respectively.
I got exactly the opposite data: 125252, 146314, 170360, and 177400.
Looking at the schematic I could only explain that by a defective 7404
hex inverter, no longer inverting the input signal. But that seemed too
weird to be true, and I was not sure whether that would be a correct
assumption anyway.
Back home I downloaded "EK-KD11B-MM-001_Jan75.pdf" as a preparation to
some microstepping/debugging of the CPU. To my surprise, in the back is
a chapter 5.11 "Console maintenance". It describes exactly the same
tests, but now the LED data is different ... it is what I am seeing!
So, I am happy to say that the console is eliminated as a problem source.
I guess that the first manual is not for the 11/10 "S" version, although
it surprises me that there would be a difference in the console hardware.
I dug up 3 double-width extender boards and the KM11 maintenance panels,
getting ready to do some microstepping as described in the manual(s).
Keeping both manuals side by side!
If you have some ideas how to proceed checking the CPU, I'm all ears!
greetz,
- Henk, PA8PDP
4 Oct
4 Oct
11:09 a.m.
Some corrections to my post regarding the console LED behavior.
Voltage levels on the CPU backplane are still good whne the 2 CPU boards
are installed in the backplane, but the processor is not responsive to
the switches on the console panel.
The RUN LED is on, ADDRESS/DATA are all off. When the HALT/ENABLE switch
is in the HALT position and START is toggled ("reset"), the RUN goes off
and the ADDRESS/DATA LEDs all go on.
LOAD ADDR, EXAM and CONT have no response.
When I set HALT/ENABLE switch to ENABLE and toggle START, the RUN LED
goes on and DATA/ADDRESS LEDs go off, except LED "0".
greetz,
- Henk, PA8PDP
11:16 a.m.
Some corrections to my post regarding the console LED
behavior.
Voltage levels on the CPU backplane are still good whne the 2 CPU boards
are installed in the backplane, but the processor is not responsive to
the switches on the console panel.
It's been a long time since I've been inside an 11/10 (that will change soon as I
fix
the one damaged by the idiot removal men,..) but just to eliminate the obvious
check that ACLO and DCLO are solidly high.
On a system like this I would always start by looking at the microcode program counter.
What state(s) is it in? If it is sequencing through states, does the sequence make any
sense?
Does anything happen when you press LOAD ADDR (say)?
Maybe start from one of the switches like LOAD ADDR and see if it is generating the right
signals on the processor board.
-tony
11:49 a.m.
-----Oorspronkelijk bericht-----
From: tony duell
Sent: Sunday, October 04, 2015 8:16 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: PDP-11/10 repair started
Some corrections to my post regarding the console LED
behavior.
Voltage levels on the CPU backplane are still good whne the 2 CPU boards
are installed in the backplane, but the processor is not responsive to
the switches on the console panel.
It's been a long time since I've been inside an 11/10 (that will change soon
as I fix
the one damaged by the idiot removal men,..) but just to eliminate the
obvious
check that ACLO and DCLO are solidly high.
On a system like this I would always start by looking at the microcode
program counter.
What state(s) is it in? If it is sequencing through states, does the
sequence make any sense?
Does anything happen when you press LOAD ADDR (say)?
Maybe start from one of the switches like LOAD ADDR and see if it is
generating the right
signals on the processor board.
-tony
=========
Oops, I forgot to mention a few other checks that I did ...
AC LO and DC LO are some 4.6V. Both have a 130 mV ripple, no spikes.
That seems OK to me.
As the console ribbon cable was disconnected, I also checked the toggle
switches (LOAD ADDR, EXAM, START, CONT, DEP) and the switches SW0~SW15
and HALT/EANBLE. In the OFF position the signal is 0.06V and in the ON
position I measured voltages between 4.5 and 4.6V. Toggles and switch
signals seems OK too.
I am fairly confident that the console itself is OK.
Thanks for the tip checking the microcode program counter. I hope to
get to that next weekend. Also, with the correct module on extenders
I will check what toggling LOAD ADDRS does signal-wise. Looking at
the console LEDs it does nothing :-/
thanks,
- Henk
12:09 p.m.
Oops, I forgot to mention a few other checks that I did ...
AC LO and DC LO are some 4.6V. Both have a 130 mV ripple, no spikes.
That seems OK to me.
Sure, those sound OK to me too. But you would have felt a right idiot if you
had spent days working through the microcode and CPU logic only
to find the real cause was something like that. Yes, I've been there,
done that...
[...]
Thanks for the tip checking the microcode program
counter. I hope to
get to that next weekend. Also, with the correct module on extenders
I will check what toggling LOAD ADDRS does signal-wise. Looking at
the console LEDs it does nothing :-/
In general on a microcoded system, assuming a listing of the microcode
is available (as here), the microcode program counter a good place
to start testing.
You should look for several things :
Is the microcode running, or is it stuck in a particular address?
If the latter, should it be stuck there, perhaps it is waiting for
some external input (like a console switch :-)). Try to find some
way of giving it that input and see what happens.
If the former, is the sequence of states reasonable (does it correspond
with something the microcode could ever do, evem if it shouldn't
be doing that now). Is it a possible sequence of states for what the
machine should be doing (What I mean here is that if the microcode
is say fetching something from memory, interpretting it as a particular
instruction, doing that, and repeating, then the microcode is doing
something that sometimes it should be doing (e.g.. when running a program)
even if it shoudn't be doing it when you have halted the machine from
the console, whereas if the microcode is jumping through an apparently
random set of states then I would suspect the microcode program
counter register, the control store ROMs, jump logic, etc.
Incidentally, is this an 11/10 or an 11/10S (what are the M-numbers on the
CPU boards)?
-tony
12:26 p.m.
-----Oorspronkelijk bericht-----
From: tony duell
Sent: Sunday, October 04, 2015 9:09 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: PDP-11/10 repair started
Oops, I forgot to mention a few other checks that I did ...
AC LO and DC LO are some 4.6V. Both have a 130 mV ripple, no spikes.
That seems OK to me.
Sure, those sound OK to me too. But you would have felt a right idiot if you
had spent days working through the microcode and CPU logic only
to find the real cause was something like that. Yes, I've been there,
done that...
[...]
Thanks for the tip checking the microcode program
counter. I hope to
get to that next weekend. Also, with the correct module on extenders
I will check what toggling LOAD ADDRS does signal-wise. Looking at
the console LEDs it does nothing :-/
[... snip good microcode stuff ...]
Incidentally, is this an 11/10 or an 11/10S (what are the M-numbers on the
CPU boards)?
-tony
=========
Tony,
the microcode is "on the menu" for next weekend ...
The system is a 11/10S, CPU is M7260 and M7261.
- Henk
12:52 p.m.
the microcode is "on the menu" for next weekend ...
The system is a 11/10S, CPU is M7260 and M7261.
Are you sure that's an 'S'? I thought the 'S' was the M8260/M8261
board
set with the links to disable the bus arbiter so it can be used as a slave
processor.
Anyway, getting back to this... I had forgotten that the 11/10 loads the LED
data serially into a shift register on the console board. Is that clock and counter
running (on the console board)? Also check round the '150 mux on the data path
board, that is the source of the bitstream for the LEDs
The switch logic seems to be sheet CONE in my printset (which is actually for
the GT40, but it's the same processor). On the control logic board, ROM
E100 seems to determine the microcode address for console operations.
Start with CONE BUT SWITCHES L, which seems to be an overall enable for this.
It starts from the '154 E078 on that board (sheet CONE again). It is controlled by
the microcode ROM E105 (sheet CONG). Microcode program counter is E102
and E091 (sheet CONF). Also look at the CPU clock (sheet CONJ). Is it running? If
not, look at those gates E013d, etc, that disable it.
That's something to be going one with anyway...
-tony
1:26 p.m.
-----Oorspronkelijk bericht-----
From: tony duell
Sent: Sunday, October 04, 2015 9:52 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: PDP-11/10 repair started
the microcode is "on the menu" for next
weekend ...
The system is a 11/10S, CPU is M7260 and M7261.
Are you sure that's an 'S'? I thought the 'S' was the M8260/M8261
board
set with the links to disable the bus arbiter so it can be used as a slave
processor.
Anyway, getting back to this... I had forgotten that the 11/10 loads the LED
data serially into a shift register on the console board. Is that clock and
counter
running (on the console board)? Also check round the '150 mux on the data
path
board, that is the source of the bitstream for the LEDs
The switch logic seems to be sheet CONE in my printset (which is actually
for
the GT40, but it's the same processor). On the control logic board, ROM
E100 seems to determine the microcode address for console operations.
Start with CONE BUT SWITCHES L, which seems to be an overall enable for
this.
It starts from the '154 E078 on that board (sheet CONE again). It is
controlled by
the microcode ROM E105 (sheet CONG). Microcode program counter is E102
and E091 (sheet CONF). Also look at the CPU clock (sheet CONJ). Is it
running? If
not, look at those gates E013d, etc, that disable it.
That's something to be going one with anyway...
-tony
=========
Yup, the clock and counter on the console board are running.
That's why the console maintenance tests 5 - 8 work, producing
the data patterns on the LEDs :-)
Thanks for the pointers! I haven't looked at the schematics yet.
Yes, it is an 11/10S.
AFAIK, the M7260 and M7261 is used in all 11/10 versions, and
of course all 11/05 versions. I could be wronge though ...
I guess you are confused with the M7265/M7266 (11/34) and
M8265/M8266 (11/34A).
- Henk
1:44 p.m.
Yes, it is an 11/10S.
How do you define '11/10S' ?
AFAIK, the M7260 and M7261 is used in all 11/10
versions, and
of course all 11/05 versions. I could be wronge though ...
The 11/05 and 11/10 are, by now, the same machine ;-). What I mean
by that is that essentially the difference was what you got with it when
you ordered it, and of course today you are not going to find the machine
exactly as DEC would have shipped it.
I guess you are confused with the M7265/M7266 (11/34)
and
M8265/M8266 (11/34A).
There are at least 2 versions of the 11/10 CPU boards. The later one, which
I thought was the 11/10S, has soldered wire links to disable the arbiter
(the 'S' meaning it can be a _S_lave processor on another machine's
Unibus). I think another link disables the built-in console port. And didn't it
use a crystal rather than RC clock for the built-in serial console port?
[The sooner I get my bookshelves made so I can find all my printsets the
better!]
You're right, I was getting confused over the M numbers. The original and later
boards seem to have the same numbers. The circuitry is very similar, but the IC
references I have given might be wrong.
-tony
- Henk
2:04 p.m.
-----Oorspronkelijk bericht-----
From: tony duell
Sent: Sunday, October 04, 2015 10:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: PDP-11/10 repair started
Yes, it is an 11/10S.
How do you define '11/10S' ?
AFAIK, the M7260 and M7261 is used in all 11/10
versions, and
of course all 11/05 versions. I could be wrong though ...
The 11/05 and 11/10 are, by now, the same machine ;-). What I mean
by that is that essentially the difference was what you got with it when
you ordered it, and of course today you are not going to find the machine
exactly as DEC would have shipped it.
I guess you are confused with the M7265/M7266 (11/34)
and
M8265/M8266 (11/34A).
There are at least 2 versions of the 11/10 CPU boards. The later one, which
I thought was the 11/10S, has soldered wire links to disable the arbiter
(the 'S' meaning it can be a _S_lave processor on another machine's
Unibus). I think another link disables the built-in console port. And didn't
it
use a crystal rather than RC clock for the built-in serial console port?
[The sooner I get my bookshelves made so I can find all my printsets the
better!]
You're right, I was getting confused over the M numbers. The original and
later
boards seem to have the same numbers. The circuitry is very similar, but the
IC
references I have given might be wrong.
-tony
=========
I define 11/10"S" by the backplane. There are 4 different backplanes
for the 11/10 and 11/05, according to the doc. I have them on my website,
www.pdp-11.nl/pdp11-05/cpu/backplanes.html
I did not know that there were different versions of the CPU boards,
except the Rev.E and Rev.F of the M7261. Good to know!
Seeing whether there is an XTAL for the console comms line is easy to
spot, but IIRC it is RC on my M7260.
- Henk
2:10 p.m.
I define 11/10"S" by the backplane. There
are 4 different backplanes
for the 11/10 and 11/05, according to the doc. I have them on my website,
www.pdp-11.nl/pdp11-05/cpu/backplanes.html
RIght...
I did not know that there were different versions of
the CPU boards,
except the Rev.E and Rev.F of the M7261. Good to know!
Seeing whether there is an XTAL for the console comms line is easy to
spot, but IIRC it is RC on my M7260.
I am working from 2 Printsets, both from Bitsavers. One is the GT40 one (yet another
backplane of course, but the same CPU, core memory, etc). That shows the older
CPU. The other is the 11/05S schematic, which shows the later boards with the
crystal UART clock, the links I ,mentioned, etc. I am sure we will get it sorted out.
As I said, the logic is much the same, certainly in the areas we need to look at first.
ICs
might have different positions, but that shouldn't be too confusing.
-tony
2:27 p.m.
On 10/4/2015 3:04 PM, Henk Gooijen wrote:
=========
I define 11/10"S" by the backplane. There are 4 different backplanes
for the 11/10 and 11/05, according to the doc. I have them on my website,
www.pdp-11.nl/pdp11-05/cpu/backplanes.html
I did not know that there were different versions of the CPU boards,
except the Rev.E and Rev.F of the M7261. Good to know!
Seeing whether there is an XTAL for the console comms line is easy to
spot, but IIRC it is RC on my M7260.
- Henk
Now did check on what version of magic smoke you got?
That may be important too.
Is there any way to tell if all the TTL was fried,
or just few chips by the wrong pins from the schematics?
Ben.
Good Luck ... this email will turn into another copy of windows in 9 8 7 ...
2:44 p.m.
I just yesterday started working on assembling an 11/05 S with a BK11-K
backplane. At the moment I am working through the power regulators to make
sure everything is right before I install the boards. I am assembling from
parts on hand but I do have the correct cards. I have M7260/61 and 8K
Core, etc. Just one 9 slot backplane. Nice simple system.
Bill
On Sun, Oct 4, 2015 at 5:27 PM, ben <bfranchuk at jetnet.ab.ca> wrote:
On 10/4/2015 3:04 PM, Henk Gooijen wrote:
--
Bill
vintagecomputer.net
=========
I define 11/10"S" by the backplane. There are 4 different backplanes
for the 11/10 and 11/05, according to the doc. I have them on my website,
www.pdp-11.nl/pdp11-05/cpu/backplanes.html
I did not know that there were different versions of the CPU boards,
except the Rev.E and Rev.F of the M7261. Good to know!
Seeing whether there is an XTAL for the console comms line is easy to
spot, but IIRC it is RC on my M7260.
- Henk
Now did check on what version of magic smoke you got?
That may be important too.
Is there any way to tell if all the TTL was fried,
or just few chips by the wrong pins from the schematics?
Ben.
Good Luck ... this email will turn into another copy of windows in 9 8 7
...
5:27 p.m.
On 2015-10-04 20:09, Henk Gooijen wrote:
Some corrections to my post regarding the console LED
behavior.
Voltage levels on the CPU backplane are still good whne the 2 CPU boards
are installed in the backplane, but the processor is not responsive to
the switches on the console panel.
The RUN LED is on, ADDRESS/DATA are all off. When the HALT/ENABLE switch
is in the HALT position and START is toggled ("reset"), the RUN goes off
and the ADDRESS/DATA LEDs all go on.
LOAD ADDR, EXAM and CONT have no response.
When I set HALT/ENABLE switch to ENABLE and toggle START, the RUN LED
goes on and DATA/ADDRESS LEDs go off, except LED "0".
You mentioned NPR problems before, but I have never seen a broken NPR
signal cause any problems at power on. Broken NPR normally cause DMA to
not work.
However, what you describe sounds exactly how I've seen a lot of
machines behave when the terminator is missing. Check for bus
continuity, and termination.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
8:58 p.m.
On 10/04/2015 01:09 PM, Henk Gooijen wrote:
Some corrections to my post regarding the console LED
behavior.
Voltage levels on the CPU backplane are still good whne
the 2 CPU boards
are installed in the backplane, but the processor is not
responsive to
the switches on the console panel.
The RUN LED is on, ADDRESS/DATA are all off.
You have no memory, and probably no
devices to complete the
Unibus. So, it is quite likely showing the Unibus is in a
jammed state. At the least, you need a Unibus terminator,
and any bus grant cards between the CPU and the terminator
(you'd have to check the manual to see how the Unibus is wired.)
Jon
10:26 p.m.
You have no memory, and probably no devices to complete the
Unibus. So, it is quite likely showing the Unibus is in a
jammed state. At the least, you need a Unibus terminator,
and any bus grant cards between the CPU and the terminator
(you'd have to check the manual to see how the Unibus is wired.)
The specific issue of an open grant chain locking the Unibus is a quirk
of the M9302 terminator (which asserts SACK under such conditions). This
is unlikely to be a problem on an 11/10.
But you do need some kind of termination/pullups on the Unibus. At least
fit the CPU-end terminator (M930 in the right slot near the CPU boards) if
you haven't done so already.
-tony
5 Oct
5 Oct
2:33 a.m.
On 2015-10-05 07:26, tony duell wrote:
Why? The 11/10 also have a Unibus, and also needs the terminator as well
as the SACK and other signals in order.
You have no memory, and probably no devices to complete the
Unibus. So, it is quite likely showing the Unibus is in a
jammed state. At the least, you need a Unibus terminator,
and any bus grant cards between the CPU and the terminator
(you'd have to check the manual to see how the Unibus is wired.)
The specific issue of an open grant chain locking the Unibus is a quirk
of the M9302 terminator (which asserts SACK under such conditions). This
is unlikely to be a problem on an 11/10. But you do need some kind of termination/pullups on
the Unibus. At least
fit the CPU-end terminator (M930 in the right slot near the CPU boards) if
you haven't done so already.
You most likely want to terminate the other end as well.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
4:50 a.m.
The specific
issue of an open grant chain locking the Unibus is a quirk
of the M9302 terminator (which asserts SACK under such conditions). This
is unlikely to be a problem on an 11/10.
Why? The 11/10 also have a Unibus, and also needs the terminator as well
as the SACK and other signals in order. But you do
need some kind of termination/pullups on the Unibus. At least
fit the CPU-end terminator (M930 in the right slot near the CPU boards) if
you haven't done so already.
You most likely want to terminate the other end as well.
7:53 a.m.
On 2015-10-05 13:50, tony duell wrote:
The M9302 includes logic to assert SACK if a grant (any BG or NPG) gets to it,
meaning no device on the bus as intercepted the grant. This causes problems
with an open grant chain in that the CPU sees the SACK, tries to deassert
the grant (which it hasn't asserted in the first place) and the bus is locked with
SACK asserted and no grants. The M930 terminator does not include said logic.
As a result an open grant chain will cause problems on a machine where the
terminator is an M9302. On a machine where it's an M930, an open grant chain
is of course a bad idea (interrupts and DMA will not work properly) but it will not
lock the bus and prevent the front panel from working.
The 11/10 generally uses an M930 terminator.
Right. However, the SACK signal exists, even on the 11/10.
And if that signal is floating, or non-working, you can still have
problems. So, termination is still important.
The additional feature of of the M9302 is just to catch if BG signals
are sent out when noone was actually requesting an interrupt.
So your comment about open grant chain locking is relevant, but do not
negate the claim that you need to make sure you have terminators in
place, and that signals are carried through the whole backplane.
Note that my original comment was not about BG/BR continuity as such,
but termination and signals running through the whole bus. BG/BR is just
one part of that.
It may not be a perfect electrical match, but if all you have is the CPU backplane,
or even a BA11-K full of backplanes, I am certain a terminator at the CPU end only
will get the machine doing something, even running programs correctly. Totally
ignoring the front panel is not caused by a missing far-end terminator on such a
small machine.
The 11/10 do not have a built-in terminator at the CPU end. You are
supposed to have two M930 on the backplane.
Johnny
The specific issue of an open grant chain locking the
Unibus is a quirk
of the M9302 terminator (which asserts SACK under such conditions). This
is unlikely to be a problem on an 11/10.
Why? The 11/10 also have a Unibus, and also needs the terminator as well
as the SACK and other signals in order. But you do need some kind of termination/pullups on
the Unibus. At least
fit the CPU-end terminator (M930 in the right slot near the CPU boards) if
you haven't done so already.
You most likely want to terminate the other end as well.
8:24 a.m.
-----Oorspronkelijk bericht-----
From: Johnny Billquist
Sent: Monday, October 05, 2015 4:53 PM
To: cctalk at classiccmp.org
Subject: Re: PDP-11/10 repair started
On 2015-10-05 13:50, tony duell wrote:
It may not be a perfect electrical match, but if all you have is the CPU
backplane,
or even a BA11-K full of backplanes, I am certain a terminator at the CPU
end only
will get the machine doing something, even running programs correctly.
Totally
ignoring the front panel is not caused by a missing far-end terminator on
such a
small machine.
The 11/10 do not have a built-in terminator at the CPU end. You are
supposed to have two M930 on the backplane.
Johnny
=========
Sorry for the delayed answer, I don't have email available at work -:/
I have one M930 in slot 3 position A-B, because that is the termination
for the processor. I am pretty sure (not 100%) that I also have an M930
in slot 9 position A-B. To be complete, this is the current state.
slot 1 A-F : M7260
slot 2 A-F : M7261
slot 3 A-B : M930 C-D : G7273
slot 4 A-B : M9970 C-D : G7273
slot 5 C-D : G7273
slot 6 empty
slot 7 empty
slot 8 empty
slot 9 A-B : M930
Slot 6-7-8-9 is for core memory, respectively G235, H217D, G114, M8293.
The documentation says that a G727 should go in slot 3-4-5 position D.
I hate those "knuckle-busters". Plus, I am lazy to check NPR continuity
on the backplane, so I installed G7273s instead of G727s. Always good.
I totally forgot that the GT40 is based on the 11/05. Great tip in case
it turns out that I have a "different" CPU module! You never know ...
When I got the 11/10, all boards were in their correct location, so after
the goof up of wrong placement, somebody more knowledgeable placed the
boards in their correct slots. I guess he hoped to see a working system.
So I do not know which board was place where :-/ That makes guessing
what might be damaged a bit tricky, although in/outs that go to fingers
of the board are first candidate for inspection. A visual check did not
reveal anything abviously blown or burnt.
@Bill : keep us posted of your progress :-)
@Johnny : I do not think an NPR problem exists, unless it is there,
because of damaged hardware.
@Jon : After I checked the correct levels of all power suplly voltages,
I also tried the system with slot 6-7-8-9 filled with the core memory.
Behavior did not change. Again, I am pretty sure NPR is not the problem.
@Noell : thanks for mentioning the possible versions! Good to keep in
mind!
As Tony says, the M930 terminator close to the CPU (slot 3) should be
enough, especially as all other slots that matter are empty. But I am
pretty sure that for 100% correctness I also have one M930 in slot 9.
Thanks for all support, I hope to continue on Saturday ...
- Henk
The 11/10 generally uses an M930 terminator.
Right. However, the SACK signal exists, even on the 11/10.
And if that signal is floating, or non-working, you can still have
problems. So, termination is still important.
The additional feature of of the M9302 is just to catch if BG signals
are sent out when noone was actually requesting an interrupt.
So your comment about open grant chain locking is relevant, but do not
negate the claim that you need to make sure you have terminators in
place, and that signals are carried through the whole backplane.
Note that my original comment was not about BG/BR continuity as such,
but termination and signals running through the whole bus. BG/BR is just
one part of that.
But you do need some kind of termination/pullups on
the Unibus. At least
fit the CPU-end terminator (M930 in the right slot near the CPU boards)
if
you haven't done so already.
You most likely want to terminate the other end as well.
8:44 a.m.
On 2015-10-05 17:24, Henk Gooijen wrote:
-----Oorspronkelijk bericht----- From: Johnny
Billquist
Sent: Monday, October 05, 2015 4:53 PM
To: cctalk at classiccmp.org
Subject: Re: PDP-11/10 repair started
On 2015-10-05 13:50, tony duell wrote:
It may not be a perfect electrical match, but if all you have is the
CPU backplane,
or even a BA11-K full of backplanes, I am certain a terminator at the
CPU end only
will get the machine doing something, even running programs correctly.
Totally
ignoring the front panel is not caused by a missing far-end terminator
on such a
small machine.
The 11/10 do not have a built-in terminator at the CPU end. You are
supposed to have two M930 on the backplane.
Johnny
=========
Sorry for the delayed answer, I don't have email available at work -:/
I have one M930 in slot 3 position A-B, because that is the termination
for the processor. I am pretty sure (not 100%) that I also have an M930
in slot 9 position A-B. To be complete, this is the current state.
slot 1 A-F : M7260
slot 2 A-F : M7261
slot 3 A-B : M930 C-D : G7273
slot 4 A-B : M9970 C-D : G7273
slot 5 C-D : G7273
slot 6 empty
slot 7 empty
slot 8 empty
slot 9 A-B : M930
Slot 6-7-8-9 is for core memory, respectively G235, H217D, G114, M8293.
The documentation says that a G727 should go in slot 3-4-5 position D.
I hate those "knuckle-busters". Plus, I am lazy to check NPR continuity
on the backplane, so I installed G7273s instead of G727s. Always good.
I totally forgot that the GT40 is based on the 11/05. Great tip in case
it turns out that I have a "different" CPU module! You never know ...
When I got the 11/10, all boards were in their correct location, so after
the goof up of wrong placement, somebody more knowledgeable placed the
boards in their correct slots. I guess he hoped to see a working system.
So I do not know which board was place where :-/ That makes guessing
what might be damaged a bit tricky, although in/outs that go to fingers
of the board are first candidate for inspection. A visual check did not
reveal anything abviously blown or burnt.
@Bill : keep us posted of your progress :-)
@Johnny : I do not think an NPR problem exists, unless it is there,
because of damaged hardware.
@Jon : After I checked the correct levels of all power suplly voltages,
I also tried the system with slot 6-7-8-9 filled with the core memory.
Behavior did not change. Again, I am pretty sure NPR is not the problem.
@Noell : thanks for mentioning the possible versions! Good to keep in
mind!
As Tony says, the M930 terminator close to the CPU (slot 3) should be
enough, especially as all other slots that matter are empty. But I am
pretty sure that for 100% correctness I also have one M930 in slot 9.
Thanks for all support, I hope to continue on Saturday ...
- Henk
Ok. I got the initial impression that you only had the CPU in. Thanks
for the expanded info.
When you don't have any core memory, I wonder if you might need bus
grants in those slots as well...? It's not as if they aren't a part of
the Unibus... Memory sits on the Unibus, just like everything else,
remember? Needs to check further if any special wiring are in place for
those slots, though.
Johnny
The 11/10 generally uses an M930 terminator.
Right. However, the SACK signal exists, even on the 11/10.
And if that signal is floating, or non-working, you can still have
problems. So, termination is still important.
The additional feature of of the M9302 is just to catch if BG signals
are sent out when noone was actually requesting an interrupt.
So your comment about open grant chain locking is relevant, but do not
negate the claim that you need to make sure you have terminators in
place, and that signals are carried through the whole backplane.
Note that my original comment was not about BG/BR continuity as such,
but termination and signals running through the whole bus. BG/BR is just
one part of that.
But you do need some kind of termination/pullups on
the Unibus. At
least
fit the CPU-end terminator (M930 in the right slot near the CPU
boards) if
you haven't done so already.
You most likely want to terminate the other end as well.
8:48 a.m.
When you don't have any core memory, I wonder if you might need bus
grants in those slots as well...? It's not as if they aren't a part of
the Unibus... Memory sits on the Unibus, just like everything else,
remember? Needs to check further if any special wiring are in place for
those slots, though.
The core memory slots are specially wired (that's why the 8K and 16K
backplanes are different, one is wired for one set of core, the other
for 2 sets, with SPCs in the remaining slots). You do NOT put grant
cards in there.
In any case, an open grant chain will not cause problems at this stage of the
11/10. If you left out all the grant continuity cards the machine would still respond
to the console switches, let you load addresses, etc. So let's get that working
first
-tony
8:56 a.m.
-----Oorspronkelijk bericht-----
From: Johnny Billquist
Sent: Monday, October 05, 2015 5:44 PM
To: cctalk at classiccmp.org
Subject: Re: PDP-11/10 repair started
Ok. I got the initial impression that you only had the CPU in. Thanks
for the expanded info.
When you don't have any core memory, I wonder if you might need bus
grants in those slots as well...? It's not as if they aren't a part of
the Unibus... Memory sits on the Unibus, just like everything else,
remember? Needs to check further if any special wiring are in place for
those slots, though.
Johnny
=========
I am not sure the "core slots" would need grant cards. The documentation
is clear about slot 3-4-5 as SPC, needing grant cards. I never saw any
doc where the core memory slots, when optional, but not installed, could
be used as an SPC slot. I certainly am Not "trying" that ...
I did try the system *with* the core slots filled with the correct boards
but the behavior remained the same.
To make fault finding not more complex, I removed the core board set.
Thanks,
- Henk
9:01 a.m.
On 2015-10-05 17:56, Henk Gooijen wrote:
-----Oorspronkelijk bericht----- From: Johnny
Billquist Sent: Monday,
October 05, 2015 5:44 PM To: cctalk at classiccmp.org Subject: Re:
PDP-11/10 repair started
Ok. I got the initial impression that you only had the CPU in. Thanks
for the expanded info.
When you don't have any core memory, I wonder if you might need bus
grants in those slots as well...? It's not as if they aren't a part of
the Unibus... Memory sits on the Unibus, just like everything else,
remember? Needs to check further if any special wiring are in place for
those slots, though.
Johnny
=========
I am not sure the "core slots" would need grant cards. The documentation
is clear about slot 3-4-5 as SPC, needing grant cards. I never saw any
doc where the core memory slots, when optional, but not installed, could
be used as an SPC slot. I certainly am Not "trying" that ...
I did try the system *with* the core slots filled with the correct boards
but the behavior remained the same.
To make fault finding not more complex, I removed the core board set.
Ok. Not sure if it makes it more complex or not, but I guess it's not
the issue right now anyway.
But my original comment about the behavior you described being very much
like what I've seen on other machines with bad/no termination still
applies. CPU seemingly stuck, but doing a master reset sortof gets it
out. But not functioning as it should.
Well, no more ideas here at the moment.
Johnny
11:59 a.m.
What are the DC LO and AC LO values off the backplane? Do they change when
you insert the CPU card. (one at a time).
On Mon, Oct 5, 2015 at 12:01 PM, Johnny Billquist <bqt at update.uu.se> wrote:
On 2015-10-05 17:56, Henk Gooijen wrote:
--
Bill
vintagecomputer.net
-----Oorspronkelijk bericht----- From: Johnny
Billquist Sent: Monday,
October 05, 2015 5:44 PM To: cctalk at classiccmp.org Subject: Re:
PDP-11/10 repair started
Ok. I got the initial impression that you only had the CPU in. Thanks
for the expanded info.
When you don't have any core memory, I wonder if you might need bus
grants in those slots as well...? It's not as if they aren't a part of
the Unibus... Memory sits on the Unibus, just like everything else,
remember? Needs to check further if any special wiring are in place for
those slots, though.
Johnny
=========
I am not sure the "core slots" would need grant cards. The documentation
is clear about slot 3-4-5 as SPC, needing grant cards. I never saw any
doc where the core memory slots, when optional, but not installed, could
be used as an SPC slot. I certainly am Not "trying" that ...
I did try the system *with* the core slots filled with the correct boards
but the behavior remained the same.
To make fault finding not more complex, I removed the core board set.
Ok. Not sure if it makes it more complex or not, but I guess it's not the
issue right now anyway.
But my original comment about the behavior you described being very much
like what I've seen on other machines with bad/no termination still
applies. CPU seemingly stuck, but doing a master reset sortof gets it out.
But not functioning as it should.
Well, no more ideas here at the moment.
Johnny
1:02 p.m.
-----Oorspronkelijk bericht-----
From: william degnan
Sent: Monday, October 05, 2015 8:59 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: PDP-11/10 repair started
What are the DC LO and AC LO values off the backplane? Do they change when
you insert the CPU card. (one at a time).
--
Bill
vintagecomputer.net
=========
I measured AC LO and DC LO with a scope while both CPU boards are in
the backplane. Both measured 4.6 V, there was a ripple of 130 mV
(looked like a sawtooth signal). I did not see spikes.
- Henk
1:23 p.m.
good news as far as power supply goes.
On Mon, Oct 5, 2015 at 4:02 PM, Henk Gooijen <henk.gooijen at hotmail.com>
wrote:
-----Oorspronkelijk bericht----- From: william degnan
Sent: Monday,
October 05, 2015 8:59 PM To: General Discussion: On-Topic and Off-Topic
Posts Subject: Re: PDP-11/10 repair started
What are the DC LO and AC LO values off the backplane? Do they change when
you insert the CPU card. (one at a time).
--
Bill
vintagecomputer.net
=========
I measured AC LO and DC LO with a scope while both CPU boards are in
the backplane. Both measured 4.6 V, there was a ripple of 130 mV
(looked like a sawtooth signal). I did not see spikes.
- Henk
--
Bill
vintagecomputer.net
6:17 p.m.
On 10/5/2015 10:24 AM, Henk Gooijen wrote:
=========
Sorry for the delayed answer, I don't
have email available at work -:/
I have one M930 in slot 3 position
A-B, because that is the termination
for the processor. I am pretty sure
(not 100%) that I also have an M930
in slot 9 position A-B. To be
complete, this is the current state.
slot 1 A-F : M7260
slot 2 A-F : M7261
slot 3 A-B : M930 C-D : G7273
slot 4 A-B : M9970 C-D : G7273
slot 5 C-D : G7273
slot 6 empty
slot 7 empty
slot 8 empty
slot 9 A-B : M930
Slot 6-7-8-9 is for core memory,
respectively G235, H217D, G114, M8293.
The documentation says that a G727
should go in slot 3-4-5 position D.
I hate those "knuckle-busters". Plus,
I am lazy to check NPR continuity
on the backplane, so I installed
G7273s instead of G727s. Always good.
I totally forgot that the GT40 is
based on the 11/05. Great tip in case
it turns out that I have a "different"
CPU module! You never know ...
Henk, I'm confused by your slot
arrangement, but maybe my 11/05 is
different than yours.
My module utilization is as follows, and
is an 8k backplane (the 16k backplane is
also different):
slot 9 A-F : M7260
slot 8 A-F : M7261
slot 7 A-F : G110
Slot 6 A-F :G231
Slot 5 AB : M930 C-F : H214
Slot 4 AB : blank C-F G727 in D4.
Slot 3 AB : M930 C-F G727 in D3
Slot 2 AB: KM11 Maint C-F G727 in D2
Slot 1 AB: DF11 Comm C-F G727 in D1
--------John
6 Oct
6 Oct
2:47 a.m.
My 11/05 S's have the names of the cards printed on the chassis wall. The
cards and their slots are listed in the 11/05 S docs. I have always
referred to these unambiguous sources. As long as you have the matching
mounting box for the version of model S of course.
Bill Degnan
twitter: billdeg
vintagecomputer.net
On Oct 5, 2015 9:17 PM, "js at cimmeri.com" <js at cimmeri.com> wrote:
On 10/5/2015 10:24 AM, Henk Gooijen wrote:
=========
Sorry for the delayed answer, I don't have email available at work -:/
I have one M930 in slot 3 position A-B, because that is the termination
for the processor. I am pretty sure (not 100%) that I also have an M930
in slot 9 position A-B. To be complete, this is the current state.
slot 1 A-F : M7260
slot 2 A-F : M7261
slot 3 A-B : M930 C-D : G7273
slot 4 A-B : M9970 C-D : G7273
slot 5 C-D : G7273
slot 6 empty
slot 7 empty
slot 8 empty
slot 9 A-B : M930
Slot 6-7-8-9 is for core memory, respectively G235, H217D, G114, M8293.
The documentation says that a G727 should go in slot 3-4-5 position D.
I hate those "knuckle-busters". Plus, I am lazy to check NPR continuity
on the backplane, so I installed G7273s instead of G727s. Always good.
I totally forgot that the GT40 is based on the 11/05. Great tip in case
it turns out that I have a "different" CPU module! You never know ...
Henk, I'm confused by your slot arrangement, but maybe my 11/05 is
different than yours.
My module utilization is as follows, and is an 8k backplane (the 16k
backplane is also different):
slot 9 A-F : M7260
slot 8 A-F : M7261
slot 7 A-F : G110
Slot 6 A-F :G231
Slot 5 AB : M930 C-F : H214
Slot 4 AB : blank C-F G727 in D4.
Slot 3 AB : M930 C-F G727 in D3
Slot 2 AB: KM11 Maint C-F G727 in D2
Slot 1 AB: DF11 Comm C-F G727 in D1
--------John
3365
days inactive
3367
days old
28 comments
7 participants
participants (7)
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ard＠p850ug1.demon.co.uk -
bfranchuk＠jetnet.ab.ca -
billdegnan＠gmail.com -
bqt＠update.uu.se -
elson＠pico-systems.com -
henk.gooijen＠hotmail.com -
js＠cimmeri.com