Re: Looking for info on memory

[Nigel Johnson Ham via cctalk]

I really appreciate that, all the things I can find under that board
number (which is simple the pcb etch) are from vendors who want to sell
you one and have no idea of the model number.

I too, have no idea of the model number, but have tried search for all
sorts of PM-MSV11 etc with no luck.

I will wait with bated breath!

cheer,

Nigel


On 2021-10-21 1:30 p.m., Derek Newland via cctech wrote:
> Hey, FoothillsGeek here! I saw this thread last night and checked to see if
> I had a manual for it - it does not look like I do. Most of the Plessey
> documents we received are for core memory boards.
>
> However, when I indexed the docs we received, I did so by model number
> (PM-) and not by part number. So, if I can find our stack of Plessey
> docs, I'll flip through them again to look for the PN.
>
> On Thu, Oct 21, 2021 at 8:49 AM steven--- via cctech 
> wrote:
>
>>> On 10/19/2021 12:57 PM, Nigel Johnson Ham via cctech wrote:
 I am trying to bring up an 11/23 system in a BA23 box, and the only
 memory i have is an obscure Plessey one. The only identification is the
 p/n 705920 with dash-100 in white ink. By counting the chips I make it
 4MB, but it does not respond. Since it takes the full 22-bit memory
 space I can't see how any jumpers would change its accessibility. Does
 anybody have a manual?
>> FoothillsGeek on VCFed had a number of Plessey memory manuals and had
>> scanned
>> some, as mentioned here
>> https://www.vcfed.org/forum/forum/genres/dec/73251-dec-documents-on-manx
>>
>>

FTGH Various DLT and 4mm DAT Drives - Midlands UK

[James Attfield via cctalk]

I’m having a general clear out and the following are free for the collection 
rather than they go in the skip/dumpster.

Most if not all were working when put away but I can’t offer any guarantees. 
Preference will be given to anyone who will take all of them.

Photos are available if required, if I get time to ge a drive on line and can 
erase tapes quite a few will be available as well.

- Compaq 20/40GB in chassis

- HP Surestore DLT40 in chassis (20/40GB?)

- Digital DLT in chassis (35/70GB)

- Compaq 35/70GB in chassis

- DLT 35/70GB in chassis (same drive as in the Digital chassis)

- DLT 35/70GB bare drive (same drive as in Digital chassis)

- 4mm DAT in chassis (probably 4/8GB) 

- 4mm DAT, 5.25” spacers, no chassis, (probably 4/8GB) 

- 4mm DAT, 5.25” spacers, no chassis, (probably 4/8GB) 

- 4mm DAT, no spacers, no chassis, (probably 4/8GB) 

They won’t be around long so with apologies, if you have any interest, please 
don’t delay. Let me kow here then we can take comms off line. Sorry, can’t ship.

—
James
---
Credentials
Loves Cromemco, loves Unix, loves DeSmet C.
Hand built an original IMSAI 8080, Nascom I and II, resurrected a TU-ART from 
the dead, owned one of the first EXIDY Sorcerers in the UK, ran Byte 
Shop/Computerland (Birmingham).

Re: Looking for info on memory

[Derek Newland via cctalk]

Hey, FoothillsGeek here! I saw this thread last night and checked to see if
I had a manual for it - it does not look like I do. Most of the Plessey
documents we received are for core memory boards.

However, when I indexed the docs we received, I did so by model number
(PM-) and not by part number. So, if I can find our stack of Plessey
docs, I'll flip through them again to look for the PN.

On Thu, Oct 21, 2021 at 8:49 AM steven--- via cctech 
wrote:

>
> > On 10/19/2021 12:57 PM, Nigel Johnson Ham via cctech wrote:
> >> I am trying to bring up an 11/23 system in a BA23 box, and the only
> >> memory i have is an obscure Plessey one. The only identification is the
> >> p/n 705920 with dash-100 in white ink. By counting the chips I make it
> >> 4MB, but it does not respond. Since it takes the full 22-bit memory
> >> space I can't see how any jumpers would change its accessibility. Does
> >> anybody have a manual?
>
> FoothillsGeek on VCFed had a number of Plessey memory manuals and had
> scanned
> some, as mentioned here
> https://www.vcfed.org/forum/forum/genres/dec/73251-dec-documents-on-manx
>
>

-- 
*Derek Newland* | (828) 234-4731 | derek.newl...@gmail.com

Re: Looking for info on memory

[Noel Chiappa via cctalk]

A couple of comments on a number of things touched on in this thread:

> From: Nigel Johnson Ham

> Ah, well there you see the end of my technical knowledge.

My observation is that since varying QBUS PDP-11 CPU's can be swapped in and
out (unlike UNIBUS PDP-11's, where the CPU's backplane and front panel are
not interchangeable between models), and QBUS machines were therefore often
upgraded over their lifetime by switching in a CPU, when starting out with a
new machine, one should _always_ start by working out what kind of QBUS
backplane one has, and going from there.

The BA23 is the one that's part Q/CD and part Q/Q.

> No, I don't know if the CPU is good (it is a dual-width KDF11-A btw),
> ...
> I do have an 11/73 dual width board arriving tomorrow
> ...
> it is crashing into ODT and not accepting input from the console, which
> I remember was a symptom of no bank 0 memory.

That's true of all LSI-11's (and it threw me for a while when we first ran
across it), but KDF11-A's and KDJ11-A's work fine with _no_ working memory in
the machine: i.e. just a CPU board and a console will work fine (as in, ODT
works, and one can examine what few registers are on the bus).

(I had previously fried the KDF11-A; just tried the KDJ11-A. Probably the
KDF11-B and KDJ11-B work too, but I'm toolazy to try them at the moment.)

So if a machine with _just_ a CPU and console doesn't work, you've got a
problem; but it shouldn't be too hard to find it, with only two boards.


> From: Joshua Rice 

>> "many boards designed for Q/CD slots (such as PMI cards) do not avoid
>> the QBUS pins on the CD connectors which contain 'hazardous' (to TTL
>> circuitry) voltages."

I should note that that text is somewhat questionable; I recently checked the
list of PMI pins, and I didn't see any that conflicted with 12V pins on Q/Q
slots.  But definitely plugging a PMI card into a Q/Q slot will damage it:
MicroNote 28 says "MSV11-J MODULES CAN[NOT] BE PLACED IN A Q/Q BACKPLANE
SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS".


> From: Jerry Weiss

> I don't believe ODT is dependent on working memory.

On LSI-11's, it us. Location 0 must respond to a read cycle, or the
CPU will spin trying to read it, _before_ ODT will start.

Noel

Re: Looking for info on memory

[Nigel Johnson Ham via cctalk]

No luck, there are no 12V traces continued to the edge connector, and
the 5VB goes to a three way jumper post where the jumper is between the
common and 5V

Besides, there are two LEDs on the board that light up, one red one green.

Thanks,

Nigel


On 2021-10-21 10:58 a.m., Chris Zach via cctalk wrote:
>
>
> On 10/21/2021 9:10 AM, Nigel Johnson Ham via cctalk wrote:
>> Thanks, but like bitsavers they are all older that the one I have.
>>
>> To be honest, I never saw anything Plessey bigger than 128kB in the
>> wild, so I have to wonder what kind of machine this board came from,
>> although it was in a pile of Qbus things that I got the J boards from.
>>
>> I'm thinking that maybe it was not sold separately, but an OEM build for
>> military etc, and perhaps it is jumpered to get power from memory - but
>> without the manual or tracing the lands I can't really tell.
>
> Wait, that could be it: If the board is jumpered to power the memory
> refresh/chips from battery then of course it wouldn't work without it.
>
> Should be easy to check: Find the battery +5 and +12 pins on the Q bus
> then use a tester meter to check from those pins to any of the jumper
> pins. If you find continuity to a jumper that is closed you might have
> identified the problem :-)

Re: Looking for info on memory

[Chris Zach via cctalk]

On 10/21/2021 9:10 AM, Nigel Johnson Ham via cctalk wrote:

Thanks, but like bitsavers they are all older that the one I have.

To be honest, I never saw anything Plessey bigger than 128kB in the
wild, so I have to wonder what kind of machine this board came from,
although it was in a pile of Qbus things that I got the J boards from.

I'm thinking that maybe it was not sold separately, but an OEM build for
military etc, and perhaps it is jumpered to get power from memory - but
without the manual or tracing the lands I can't really tell.


Wait, that could be it: If the board is jumpered to power the memory 
refresh/chips from battery then of course it wouldn't work without it.


Should be easy to check: Find the battery +5 and +12 pins on the Q bus 
then use a tester meter to check from those pins to any of the jumper 
pins. If you find continuity to a jumper that is closed you might have 
identified the problem :-)

Re: Looking for info on memory

[Jerry Weiss via cctalk]

On 10/20/21 7:10 PM, Nigel Johnson Ham via cctalk wrote:

Thanks for that, but unfortunately it is crashing into ODT and not
accepting input from the console, which I remember was a symptom of no
bank 0 memory.

Now,of course, it could be the receiver chip in the J board (I used to
make a lot of money changing them ) but I have tried two separate J boards.

Of course if it is 4 MB, it must be in bank zero.

cheers,

Nigel


Can you read any of the CSR registers built into the serial board or cpu 
without the memory card inserted?   I don't believe ODT is dependent on 
working memory.

Re: Looking for info on memory

[Nigel Johnson Ham via cctalk]

Thanks, but like bitsavers they are all older that the one I have.

To be honest, I never saw anything Plessey bigger than 128kB in the
wild, so I have to wonder what kind of machine this board came from,
although it was in a pile of Qbus things that I got the J boards from.

I'm thinking that maybe it was not sold separately, but an OEM build for
military etc, and perhaps it is jumpered to get power from memory - but
without the manual or tracing the lands I can't really tell.

cheers,

Nigel



On 2021-10-21 7:25 a.m., Steve Malikoff via cctalk wrote:
>> On 10/19/2021 12:57 PM, Nigel Johnson Ham via cctech wrote:
>>> I am trying to bring up an 11/23 system in a BA23 box, and the only
>>> memory i have is an obscure Plessey one. The only identification is the
>>> p/n 705920 with dash-100 in white ink. By counting the chips I make it
>>> 4MB, but it does not respond. Since it takes the full 22-bit memory
>>> space I can't see how any jumpers would change its accessibility. Does
>>> anybody have a manual?
> FoothillsGeek on VCFed had a number of Plessey memory manuals and had scanned
> some, as mentioned here
> https://www.vcfed.org/forum/forum/genres/dec/73251-dec-documents-on-manx
>

Re: Looking for info on memory

[Steve Malikoff via cctalk]

> On 10/19/2021 12:57 PM, Nigel Johnson Ham via cctech wrote:
>> I am trying to bring up an 11/23 system in a BA23 box, and the only
>> memory i have is an obscure Plessey one. The only identification is the
>> p/n 705920 with dash-100 in white ink. By counting the chips I make it
>> 4MB, but it does not respond. Since it takes the full 22-bit memory
>> space I can't see how any jumpers would change its accessibility. Does
>> anybody have a manual?

FoothillsGeek on VCFed had a number of Plessey memory manuals and had scanned
some, as mentioned here
https://www.vcfed.org/forum/forum/genres/dec/73251-dec-documents-on-manx

Re: Looking for info on memory

[Nigel Johnson Ham via cctalk]

Thank you Josh, my next move will be to get a different memory.

Like you say, Even an MSV11DDD will help sort it out. I only need enough
to get into ODT, and maybe run some XXDP.  I have tried two CPUs and two
J boards, so it is either the memory of backplane!

cheers,

Nigel


On 2021-10-21 4:29 a.m., Joshua Rice via cctech wrote:
>
>
>
> -- Original Message --
> From: "Nigel Johnson Ham via cctech" 
> To: "Jerry Weiss via cctech" 
> Sent: Thursday, 21 Oct, 2021 At 01:10
> Subject: Re: Looking for info on memory
> Thanks for that, but unfortunately it is crashing into ODT and not
> accepting input from the console, which I remember was a symptom of no
> bank 0 memory.
> Now,of course, it could be the receiver chip in the J board (I used to
> make a lot of money changing them ) but I have tried two separate J
> boards.
> Of course if it is 4 MB, it must be in bank zero.
> cheers,
> Nigel
>
>
>
> I've not had any experience with third-party Q-BUS modules, with
> nearly all my PDP-11's being built out of DEC cards, purely for the
> reason that documentation is easy to find. However, one thing i do
> remember reading up on is this: "NOTE WELL: For reasons which seem
> utterly incomprehensible, many boards designed for Q/CD slots (such as
> PMI   cards) do
> not avoid the QBUS pins on the CD connectors which contain 'hazardous'
> (to TTL circuitry) voltages. Plugging such a card into a Q/Q backplane
> will generally destroy the card."
> https://gunkies.org/wiki/QBUS#Backplanes
>  .
>
>
> Some of the later quad-height DEC memory modules had either jumpers or
> resistors/fuses/not-sure-what-they-are that could be snipped out to
> convert between Q/Q and Q/CD slots. I've seen this on MSV11-P cards.
> It's entirely possible that the card wasn't configured correctly, and
> at some point got fried by the mismatch between Q/CD and Q/Q.
>
> I would definitely recommend obtaining another memory board and swap
> it in. Smaller capacity QBUS memory boards are usually quite cheap and
> plentiful, so getting a 64K/128k card isn't impossible and won't break
> the bank. It would at least help diagnose if it's the memory board, or
> if the issues are deeper seated in your backplane or CPU module.
>
> I would also add, make sure your backplane is clean and not damaged.
> It's an easy thing to overlook, but corrosion, damaged traces, damaged
> pins, and general detritus can lead to all sorts of funky malfunctions.
>
> Cheers
>
> Josh Rice
>

Re: Looking for info on memory

[Joshua Rice via cctalk]

-- Original Message --
From: "Nigel Johnson Ham via cctech" 
To: "Jerry Weiss via cctech" 
Sent: Thursday, 21 Oct, 2021 At 01:10
Subject: Re: Looking for info on memory
Thanks for that, but unfortunately it is crashing into ODT and not
accepting input from the console, which I remember was a symptom of no
bank 0 memory.
Now,of course, it could be the receiver chip in the J board (I used to
make a lot of money changing them ) but I have tried two separate J 
boards.

Of course if it is 4 MB, it must be in bank zero.
cheers,
Nigel



I've not had any experience with third-party Q-BUS modules, with nearly 
all my PDP-11's being built out of DEC cards, purely for the reason that 
documentation is easy to find. However, one thing i do remember reading 
up on is this: "NOTE WELL: For reasons which seem utterly 
incomprehensible, many boards designed for Q/CD slots (such as PMI 
  cards) do not 
avoid the QBUS pins on the CD connectors which contain 'hazardous' (to 
TTL circuitry) voltages. Plugging such a card into a Q/Q backplane will 
generally destroy the card." https://gunkies.org/wiki/QBUS#Backplanes 
 .



Some of the later quad-height DEC memory modules had either jumpers or 
resistors/fuses/not-sure-what-they-are that could be snipped out to 
convert between Q/Q and Q/CD slots. I've seen this on MSV11-P cards. 
It's entirely possible that the card wasn't configured correctly, and at 
some point got fried by the mismatch between Q/CD and Q/Q.


I would definitely recommend obtaining another memory board and swap it 
in. Smaller capacity QBUS memory boards are usually quite cheap and 
plentiful, so getting a 64K/128k card isn't impossible and won't break 
the bank. It would at least help diagnose if it's the memory board, or 
if the issues are deeper seated in your backplane or CPU module.


I would also add, make sure your backplane is clean and not damaged. 
It's an easy thing to overlook, but corrosion, damaged traces, damaged 
pins, and general detritus can lead to all sorts of funky malfunctions.


Cheers

Josh Rice