Re: plated wire memory

2019-10-20 Thread Jon Elson via cctalk

On 10/20/2019 09:45 AM, Nigel Johnson via cctalk wrote:
I remember an IBM engineer talking about this at our ham 
radio club. The wire was coiled inside a drum and pulses 
were sent down the wire.  The 'read head' was  a magnetic 
pickup at the other end of the coil - and access time was 
however long it took the pulse to arrive at the other 
end.  Therefore storage capacity was inversely 
proportional to data quantity, however at that time I was 
working with 660kB Univac FH330 drums for swapping and the 
2-ton Fastrand for 164kB of long-term storage, so it has 
to be taken in context!


No, that is acoustic delay line memory, and is a serial 
access type of data storage  All data is lost if the 
equipment is powered down. Plated wire memory is a 
random-access type of memory using principles similar to 
core memory, except the magnetic material is a magnetic film 
plated onto the copper wires.  There are a few other forms 
of NDRO such as Biax that use cores with two holes in them, 
one for the sense/inhibit wire and one for the select wires.


Jon


Re: IBM MST extender cards

2019-10-11 Thread Jon Elson via cctalk

On 10/11/2019 03:50 AM, jim stephens via cctalk wrote:



On 10/10/2019 10:49 AM, Al Kossow via cctalk wrote:

https://www.ebay.com/itm/352810055470

are these extender cards for IBM MST modules?


Oh, and by the way, that is an UNWRAPPING tool in the 
picture, not a wire-wrap tool.  (I have both.)


Jon


Re: Nuke Redmond!

2019-10-07 Thread Jon Elson via cctalk

On 10/07/2019 12:26 PM, Chuck Guzis via cctalk wrote:


I hear you--I've been on Linux for day-to-day stuff for quite a few
years, but keep a copy of XP on VirtualBox just in case.

Some of the older systems that I have legacy peripherals in also require
Windows, but it's all old versions.

I recently convinced my lovely wife to make the leap to Linux.   She
really likes it.

I've been using Linux since 1998 when I started using the 
EMC program for CNC machines, which ran on a real time 
version of Linux.  I quickly saw I could do most normal 
things better on Linux.
I now use Win XP and Win 7 for just a FEW programs which are 
not available on Linux.  One is an old but VERY good 
electronic CAD package (Protel 99 SE, the 99 kind of gives 
away the vintage!)
and my yearly tax filing program, which now required Win 7.  
I run these as needed in a virtual machine.  First I used 
VMware, but later moved to Virtual Box.


My family used Linux when here, but they have all moved out 
now, one daughter has a Dell laptop that I set up with 
Linux, and my wife uses Linux and they both find it works 
quite well for them.


Jon


Nat Semi MM5262N available

2019-10-02 Thread Jon Elson via cctalk
I have about 240 pieces of the national Semiconductor 
MM5262N 2K x 1 DRAM chips.
They appear to be unused, in aluminum (not plastic) tubes.  
Chips are plastic packaged.

365 ns access time, 475 ns read cycle.

Anybody need them to fix an old computer?

Jon


ECL static RAM ( 10144L)

2019-10-02 Thread Jon Elson via cctalk
I have 400 pieces of Signetics 10144L ECL static RAM chips.  
Anybody need some?
These were salvaged from boards by a surplus dealer 
(Alltronics, I think).
They are a 256 X 1 bit RAM, somewhere around 20 ns access 
time, ceramic package.


Jon


Re: SGI Challenge M memory boards

2019-10-02 Thread Jon Elson via cctalk

On 10/02/2019 12:18 PM, Dennis Grevenstein via cctech wrote:

Hi,

Jon wrote:

I have 15 pieces of memory SIMMs for the Challenge M series
(funny, seems like there should be an even #).  Pics here :

http://pico-systems.com/images/SGIChallenge.JPG

A Challenge M is basically a server variant of an Indigo2.
What you have looks like memory for a Challenge L or Onyx.


OK, it was some time ago, it well could be a Challenge L.  
it was a big box, and was powered by a big 28 V power 
supply.  (Or, was it a 48 V supply?)


Jon


SGI Challenge M memory boards

2019-10-01 Thread Jon Elson via cctalk
I have 15 pieces of memory SIMMs for the Challenge M series 
(funny, seems like there should be an even #).  Pics here :

http://pico-systems.com/images/SGIChallenge.JPG

Jon


Re: RAMTEK memory boards FTGH

2019-10-01 Thread Jon Elson via cctalk

On 09/30/2019 08:21 PM, Jon Elson via cctalk wrote:
I have 20 RAMTEK memory boards from late '80s frame 
buffers.  They each have 20 TMS4161-20NL video RAM chips 
on them.  The RAMTEK part # is ASSY 510857


Anyone have any interest?

Jon


Here's a pic : http://pico-systems.com/images/RAMTEK.JPG

So, this set has 400 pieces of the TMS4161-20NL, and they 
could be salvaged, if you wanted to.


Jon


Re: Standard Engineering CAMAC crate controller with LSI-11

2019-10-01 Thread Jon Elson via cctalk

On 09/30/2019 09:17 PM, Adrian Stoness via cctalk wrote:

just a box of boards or a system missing a memoru module?
Here's the LSI11/2 module : 
http://pico-systems.com/images/CAMACLSI.JPG


Here's the CAMAC interface : 
http://pico-systems.com/images/CAMACintf.JPG


Here's the panel label : 
http://pico-systems.com/images/CAMAClabel.JPG


And here's the serial interface : 
http://pico-systems.com/images/CAMACser.JPG


Jon


Re: Tek 500 pulser modules

2019-10-01 Thread Jon Elson via cctalk

On 10/01/2019 08:02 AM, Al Kossow via cctalk wrote:
http://www.pulseinstruments.com/plugins/PI-451A_Users_Manual.pdf 



100ns to 100us with MOS outputs


Wow, good find!  Thanks,

Jon


Re: Standard Engineering CAMAC crate controller with LSI-11

2019-09-30 Thread Jon Elson via cctalk

On 09/30/2019 09:17 PM, Adrian Stoness via cctalk wrote:

just a box of boards or a system missing a memoru module?

OK, if you are not familiar with it, CAMAC is a standard for 
data acquisition and control, that has 25-slot powered 
crates.  At the right edge, the last 2 slots are dedicated 
as controller slots.
This was a 3-slot set that could be used as a programmable 
controller for the CAMAC crate.

So, it has 3 CAMAC modules, one of which has the LSI11/2 in it.
But, since the LSI11/2 doesn't have memory on board, and the 
other boards don't seem to have any memory, it seems 
something is missing.  I think there must have been a 4th 
module that communicated by a ribbon cable across the 
front.  It may still be around here...


Jon


Chabin TLC cables

2019-09-30 Thread Jon Elson via cctalk
I have some bundles of Chabin TLC (transmission line cables) 
from a Memorex 3674 disk control.
This is the exact same material used in IBM 360s.  It has 18 
signal conductors and 36 grounds.
They are about 3 feet long, and I have something like 11 of 
them.


Any interest?

Jon


Tek 500 pulser modules

2019-09-30 Thread Jon Elson via cctalk
I have 3 units of the Pulse Instruments PI-451A programmable 
pulse driver.  One has a note that it is bad.  These seem to 
be general purpose pulse generators, capable of +/- 25 V 
into 50 Ohms (but that is just from reading the labels on 
the panel.)


Anybody have a use for them?  If I had a 500 bin I could 
probably use them, but I don't.


Jon


Standard Engineering CAMAC crate controller with LSI-11

2019-09-30 Thread Jon Elson via cctalk
I have a 3-board set, a Standar Engineering MIK-11/2, which 
is a controller for a CAMAC crate, with an LSI-11/2 (M7270) 
in it.  It also has a serial port in it.  I thought there 
was a memory that went with it, but I can't seem to find that.


Anybody have any use for this?

Jon


RAMTEK memory boards FTGH

2019-09-30 Thread Jon Elson via cctalk
I have 20 RAMTEK memory boards from late '80s frame 
buffers.  They each have 20 TMS4161-20NL video RAM chips on 
them.  The RAMTEK part # is ASSY 510857


Anyone have any interest?

Jon


Re: Tandem Minicomputers

2019-09-30 Thread Jon Elson via cctalk

On 09/29/2019 11:46 PM, Jason T via cctalk wrote:

Well I said no more computers I can't lift, but exotic systems keep
finding me.  So today we pulled a Tandem CLX out of a basement, along
with a few boxes of docs, 9-track tapes and random odd and ends:

https://photos.app.goo.gl/m2N7RKN3JXcmVTUC8

There's such as thing as "so obscure that no one knows/cares about
it".  I've had those before.  Do I have another?  It sure is heavy.

-j

Tandem was hot stuff back in the 1980's.  These appear to be 
the last gasp of their technology.
Once you had fast networking between processors, the whole 
Tandem concept became pretty easy to do on a few ordinary 
processors, without special hardware.  So, their whole 
reason for being became moot.


Jon


Re: PBXes at home

2019-09-24 Thread Jon Elson via cctalk

On 09/20/2019 11:12 AM, Jon Elson via cctalk wrote:



On 9/19/19 7:27 PM, Ethan O'Toole via cctalk wrote:

Where does one find a working 5ESS for home?



5ESS?  Hmmm, you must have a pretty BIG home, no?
I've had a tour of a 5ESS and it was QUITE big, like 50K 
square feet at least, not counting the battery room and 
the cross connect frames, or the Solar turbine generator.


Jon

Hmmm, I think I was confused.  I think the system I saw was 
a #3 ESS, not a #5 ESS.


Jon


Tek logic analyzer probes available

2019-09-24 Thread Jon Elson via cctalk

I have 6 Tek logic analyzer probes available.

I have one P6464 pattern generator probe with a message 
about some bad channels (could have been the cable or pat 
gen board, too).


There are 3 X P6452 analysis probes, and 2 X P6451.

Anybody need any of these?

Thanks,

Jon


Re: PBXes at home

2019-09-20 Thread Jon Elson via cctalk




On 9/19/19 7:27 PM, Ethan O'Toole via cctalk wrote:

Where does one find a working 5ESS for home?



5ESS?  Hmmm, you must have a pretty BIG home, no?
I've had a tour of a 5ESS and it was QUITE big, like 50K 
square feet at least, not counting the battery room and the 
cross connect frames, or the Solar turbine generator.


Jon


Re: PBXes at home

2019-09-19 Thread Jon Elson via cctalk

On 09/19/2019 09:27 PM, Ethan O'Toole via cctalk wrote:


A number of years ago I picked up a Lucent Merlin Legend 
system. It was around 1999, and Lucent wouldn't certify 
the system for "y2k" so this business switched over to a 
Nortel in a giant middle finger to lucent.


About 30 years ago, I had a KTU 1A2 phone system in my 
house.  I was trying to add an intercom/paging system to it 
when I was able to buy an NEC Electra 8/16 phone system.
I ran that for 25 years or so, and finally the thing just 
died.  It did paging, intercom, and general PBX 
functionality for the two lines we had.


I now have an Asterisk PBX system with 4 Snom 300 VOIP 
phones.  It does way more than the NEC Electra, but it is 
more complicated to use.  I STILL haven't gotten used to 
transferring a call to another extension or paging.  But, it 
does offer distinctive ring, auto-answer with message 
recording, and taking FAXes.


Jon




Re: phone systems, old and less-old

2019-09-18 Thread Jon Elson via cctalk

On 09/18/2019 09:23 PM, Fred Cisin via cctalk wrote:
Please don't let anybody call the 25 pair 50-pin 
miniature ribbon

connector (RJ21),  "Centronics"!


On Wed, 18 Sep 2019, Chuck Guzis via cctalk wrote:
We used to call them "blue ribbon" connectors.  I'm sure 
that that's

also a misnomer.


I still believe that that is the correct name.
I've always assumed that that was Amphenol's name for that 
line of connector when they invented it.  I also assumed 
that "blue ribbon" was a reference to the blue first-prize 
ribbons at county fair type contests.


Although a friend claimed that that name was 
unintentional, since instead of pins, it uses "ribbon 
contacts", hence also "micro ribbon connector". and many 
of them had a BLUE plastic center section.


The original Amphenol connector was about 3 X the contact 
spacing of the micro-blue ribbon
connector, but basically the same design.  They used Diallyl 
pthalate insulators.  I don't know if these are just always 
dyed blue, or the chemical makeup makes them blue, but it is 
a deep blue color.  So, that's where the blue in the name 
comes from.  The contacts are punched out of a ribbon of 
gold-plated beryllium copper, so that's where the ribbon in 
the name comes from.


Jon


Re: phone systems, old and less-old

2019-09-18 Thread Jon Elson via cctalk

On 09/18/2019 08:27 PM, Fred Cisin via cctalk wrote:

On Wed, 18 Sep 2019, Jon Elson via cctalk wrote:
Oh, my Gosh!  the first 3 pics are of a KTU phone 
system.  If you are OLD enough, remember the phones with 
5 line select buttons and a red hold button below the 
rotary dial?  That is what that unit supports, the 565 
phone.


Please don't let anybody call the 25 pair 50-pin miniature 
ribbon connector (RJ21),  "Centronics"!



Nope, AMP mini-blue ribbon.

Jon


Re: phone systems, old and less-old

2019-09-18 Thread Jon Elson via cctalk

On 09/18/2019 01:32 PM, jwest--- via cctalk wrote:

I know some peeps here are phone pholks…..See www.ezwind.net/phonestuff 


  



Oh, my Gosh!  the first 3 pics are of a KTU phone system.  
If you are OLD enough, remember the phones with 5 line 
select buttons and a red hold button below the rotary dial?  
That is what that unit supports, the 565 phone.


Jon


Re: Fwd: VAX + Spectre

2019-09-17 Thread Jon Elson via cctalk

On 09/17/2019 08:55 AM, Paul Koning via cctalk wrote:

"Spectre" is one of two notorious bugs of modern CPUs involving speculative 
execution.  I rather doubt that VAX is affected by this but I suspect others here have a 
lot more knowledge.


You need an extremely high resolution timer to detect slight 
differences in execution time of speculatively-executed 
threads. The VAX 11/780 certainly did not do speculative 
execution, and my guess is that all VAXen did not, either.  
Also, I don't think the timer was high enough resolution to 
detect such a difference.


The Alpha did do speculative execution, so it is remotely 
possible that you could play such games on that platform.


Without a deep understanding of how these exploits really 
work, I'm still a bit skeptical that it could actually be 
performed on real-world systems in a shared host data center.


Jon


Re: Mohawk Data Sciences 6401 Schematic?

2019-09-07 Thread Jon Elson via cctalk

On 09/07/2019 08:11 PM, Cory Heisterkamp via cctalk wrote:

Hey Guys,

I recently picked up an MDS 6401 Key-To-Tape unit in NCR guise to park next to 
my keypunches. It's been in storage for a couple decades and is in pretty 
decent shape. Even has a tape on it from when the university that had it pulled 
the plug and sent it off for surplus. Found an internal date code of 1971.

The unit does actually show signs of life, but I suspect a power supply issue. 
Does anyone have a lead on a schematic?

This here is basically what I'm working with: 
http://www.thecorememory.com/NCR_C-735_-_MDS_6401_Memories.pdf

Thanks,
Cory
Wow, MDS was a REALLY small outfit.  Or. maybe there was 
another company in a related field with the same acronym 
MDS.  They made some systems for accounting, order entry and 
such that were not computer-based.  The data was stored on a 
4' diameter fixed-head disk, and they had a bunch of 
stations that looked like fancy desk calculators.  All the 
logic was in the stations, and was implemented with about 50 
ICs and wire-wrap.  But, I'm pretty sure this was made by 
Mohawk Digital Sciences.


I got a Pertec key to tape system on the surplus market in 
about 1981 or so.  It had a little core memory, a keyboard 
and a panel of lights so you could step through a record and 
view the characters. It came from the surplus outfit with 
schematics.  I found the right place to break into the logic 
and interfaced it to my Z-80 CP/M system.  I used it for 
backup.  (I added a Memorex SASI-bus 8" hard drive to the 
CP/M system, and didn't really trust the reliability of 
floppies, so mag tape was a good thing to use.)


Jon


Re: Shipping from Europe to USA

2019-08-24 Thread Jon Elson via cctalk

On 08/24/2019 04:06 PM, Peter Coghlan via cctalk wrote:


What use is insurance?  If the unique machine that you have been searching for
for so long it destroyed in shipping, the insurance company pays you less
than it's value
It seems shippers have some label or something that 
identifies high-value packages, and if one gets damaged, 
some manager comes down hard on the person who did it.  So, 
packages that are insured for higher values are USUALLY 
treated with greater care.  Accidents can happen, of course.


There also seems to be a BIG difference in the usual level 
of care provided by different shippers.
I have had several things smashed by UPS, some of them 
REALLY took a lot of effort to smash.
I have NEVER had even the SLIGHTEST damage with FedEx, even 
their ground service.

This could just be statistical chance, but I don't think so.

I also had several international shipments with the US Post 
Office just totally disappear if I forgot to insure them.  
Never had one damaged or lost if insured.


Jon


Re: bit-slice and microcode discussion list

2019-08-23 Thread Jon Elson via cctalk

On 08/23/2019 12:47 PM, Noel Chiappa via cctalk wrote:

 > From: Jon Elson

 >> On 08/22/2019 12:47 PM, Tom Uban via cctalk wrote:

 >> On a possible related note, I am looking for information on converting
 >> CISC instructions to VLIW RISC.

 > I think it might end up looking a bit like the optimizers that were
 > used on drum memory computers back in the dark ages.

I dunno; those were all about picking _addresses_ for instructions, such
that the next instruction was coming up to the heads as the last one
completed.


Right, but the idea is to schedule memory reads way in 
advance of when the datum is required for a calculation.  
So, the load from memory to register is moved way up in the 
program, and the use of the register is much later to allow 
for the memory latency.  Yes, it is not exactly like drum 
memory computers, but you are still scheduling things for 
when they can be done without causing a stall.


Jon


Re: bit-slice and microcode discussion list

2019-08-23 Thread Jon Elson via cctalk

On 08/22/2019 12:47 PM, Tom Uban via cctalk wrote:

On 8/22/19 12:16 PM, Eric Smith via cctalk wrote:

On another mailing list, someone asked if there was any list specifically
about bit-slice design and microcoding. I don't know of one, so I've
created a new mailing list specifically for those topics:

 http://lists.brouhaha.com/mailman/listinfo/bit-slicers

The intent is for the list to cover technical discussion of bit-slice
hardware design and/or microcoding. In other words, discussion of
microcoding that doesn't use bit-slice hardware is fine.


On a possible related note, I am looking for information on converting
CISC instructions to VLIW RISC.


Wow, I think that ends up looking like a compiler, or at 
least the optimizing back end part of a compiler.  I worked 
a bit with a Trace Multiflow, and their optimizing back end 
was VERY slow, which I assume means it was a complex task to 
reorder all the atomic operations and pack into the long 
instruction words for best throughput.


I think it might end up looking a bit like the optimizers 
that were used on drum memory computers back in the dark ages.


Jon


Re: Shipping from Europe to USA

2019-08-22 Thread Jon Elson via cctalk

On 08/22/2019 02:09 PM, Paul Koning via cctalk wrote:
Many ages ago, I worked for a company that made 12-bit 
computers for radiation treatment planning.  they palleted a 
computer and shipped it to Holland for a trade show.  At the 
arrival airport, somebody pushed it out of the cargo bay 
with no conveyor belt below, and it fell something like 30 
feet to the ground.  the pallet was reduced to splinters, 
and the case of the machine was seriously MASHED.  The techs 
who were going to set it up didn't think it had any chance 
of working, but they pulled all the boards, beat on the case 
some to straighten it, put the boards back in, and it fired 
right up!  The machine was later returned to the US and was 
used as a

"test mule".

Jon


Re: S/23 machine update card

2019-08-18 Thread Jon Elson via cctalk



On 08/18/2019 06:38 PM, Dennis Boone via cctalk wrote:

Folks,

I've determined that the piece of my S/23 that's causing the power
supply to blow its 12V fuse is the machine update card.  The manual says
this provides additional R/W storage for microprogram updates.  That
sounds like something that wouldn't be necessary for normal operation.


Not knowing anything about this system, but you might check the card for 
a bad Tantalum capacitor.


Jon


Re: Grid 1537 ”Tempest” schematics

2019-08-17 Thread Jon Elson via cctalk

On 08/16/2019 02:20 PM, Torfinn Ingolfsen via cctalk wrote:

On Fri, Aug 16, 2019 at 1:16 AM Curt Vendel via cctalk
 wrote:

The owner tried them... Grid told him the design is owned by the US Govt
and only they have the technicals on it... I was just hoping someone

Aha. Perhaps your friend should try a FOIA request  then? Not sure
that would work.


It probably won't.  TEMPEST technology is at some level of 
secret, and even though particular machines are not 
classified, the technical means used and the testing 
protocols to get them to meet TEMPEST requirements ARE 
secret, still, as far as I know.


Jon


Re: GW-DEC-1: A New DEC Prototyping Board

2019-08-16 Thread Jon Elson via cctalk

On 08/16/2019 05:59 PM, Noel Chiappa via cctalk wrote:

 > From: Brent Hilpert

 > I've seen pieces of HP high-end lab equipment from thru the 60s that
 > used tin plating on the PCB edge fingers, mating into gold-plated edge
 > connectors on the backplane.

ISTR that DEC used bronze contacts in their backplanes, but basically all the
boards had gold-plated fingers. (I think I've seen a few power supply boards
that had tinned fingers.)

I think the bronze was preferred since the contacts bend back and forth as
cards are inserted/removed, and bronze is more durable; and being part tin,
has the same corrosion characteristics are the tin.

Noel

The contacts were mostly phosphor bronze, but they had a 
little spot of selectively plated gold where the PC board 
finger actually wiped.  I think they used basically the same 
technology from the PDP-8 era to the VAX 7xx series.


Jon

Jon


Re: GW-DEC-1: A New DEC Prototyping Board

2019-08-16 Thread Jon Elson via cctalk

On 08/16/2019 08:59 AM, systems_glitch via cctalk wrote:

Paul,

I've got a board house I usually use, but if I can find a shop in the USA
that will do hard gold plating and provide a comparable cost-per-board, I'd
certainly switch!


There are few board houses in the US anymore, and they are 
usually doing aerospace or government work, and are quite 
expensive.  Most of the supposedly US-based outfits now do 
almost all their fabrication in China.


I use E-teknet, based in AZ, but their fabs are in China.  
They do VERY good work.  In the distant past I did a lot of 
boards with US makers, but had a constant problem that they 
would charge me for electrical test, and then just cheat and 
NOT actually test the boards, just do a visual inspection.  
So, I ended up with 4-layer boards with shorts on the inner 
layers!  And, only found those after stuffing the boards.  A 
MAJOR pain, and I would blacklist those companies.
Well, E-teknet has never done that to me.  (The flying probe 
tester leaves TINY dots on the pads, so you can tell whether 
a board has been tested or not.)


Jon


Re: Archiving information, was Re: ADM-3A question

2019-08-16 Thread Jon Elson via cctalk

On 08/16/2019 02:50 AM, Christian Corti via cctalk wrote:

On Thu, 15 Aug 2019, Noel Chiappa wrote:
An additional issue, I think, is that Google is 
deprecating sites that use
HTTP, versus HTTPS. I can't comment more, lest I start 
ranting at the utter


Not true, in contrary, Google even crawls through FTP 
sites :-)


I kind of wonder what this is all about?  I mean, why do you 
have to encrypt today's weather report, a company's public 
web page, and such stuff.  Just to waste CPU time?


Jon


Re: Pertec Interface Cable Length

2019-08-13 Thread Jon Elson via cctalk

On 08/11/2019 08:00 PM, Douglas Taylor via cctech wrote:



This is where the electrical engineer could help.  How do 
you determine how long a cable the 74LS240 can drive?


Well, there are several considerations.  First, it takes 
some current to charge up the cable capacitance.  More 
current charges the capacitance faster, but also creates 
faster edges which cause more crosstalk.  Then, the data 
rate needs to be considered.  Mag tape data rates are not 
that high.  So, for 1600 BPI at 45 IPS, the data rate is 72 
K bytes/second, or about 14 us per byte.


Twisted-pair cable should have a little less capacitance, 
and it is supposed to reduce crosstalk, so should work better.


The most serious problem is when many data lines switch at 
the same time, it may contaminate the clock pulses and cause 
bytes to be dropped or added.


With the low data rates involved, proper delays to allow 
ringing to settle on the data lines and prevent short 
crosstalk pulses from affecting the clocks should make the 
system very tolerant of cable issues.  But, maybe some 
engineers didn't really optimize their logic for these problems.


Jon


Re: Pertec Interface Cable Length

2019-08-12 Thread Jon Elson via cctalk

On 08/11/2019 11:11 AM, W2HX via cctech wrote:

I seem to remember they were ribbon cables
with each odd/even pair twisted which probably meant one
active and one ground twisted together.

Or differential pairs.


No, both Pertec unformatted and Pertec formatted interfaces 
were TTL single-ended.


Jon


Re: Pertec Interface Cable Length

2019-08-11 Thread Jon Elson via cctalk

On 08/11/2019 10:40 AM, Nigel Johnson via cctalk wrote:
It's funny how licensing bodies do not recognise computer 
engineers. I am a member if the IEEE, but since I first 
wrote to the local body in 1974 they have never recognised 
computer engineering as a discipline.  After twenty years 
of chip-level troubleshooting on DEC machines I spent 
twenty twenty-five years teaching college before retiring 
to my soon-to-be-restored collection of old kit.


I ran into the then President of the provincial licensing 
association at an alumni event a few years ago and he 
laughed, saying they are still working on it!


Well, "computer engineering" isn't well-defined.  For EE, 
you can write loop and node equations and solve, and 
determine exactly how an electrical network will behave.


They are trying to make systems that can analyze computer 
programs in the same way, but I think we are pretty far from 
that level of rigor.


Jon


Re: Pertec Interface Cable Length

2019-08-11 Thread Jon Elson via cctalk

On 08/10/2019 01:29 PM, Dave Wade via cctalk wrote:



-Original Message-
From: cctech  On Behalf Of Mark J. Blair
What term is used there for an engineer
who works in fields of general electronics?


An electronics engineer...
This war was settled in 1963 when the American Institute of 
Electrical Engineers merged with the Institute of Radio 
Engineers, realizing their battle was just silly and 
counterproductive.


It was time, as serious electronics was moving into 
telecommunications and computers, numerically controlled 
machine tools, aviation, and more.  If they had a separate 
institute for each area of specialization, it would just 
dilute the  resources. Every one of them used Ohms law and 
its derivatives.


Jon


Re: Pertec Interface Cable Length

2019-08-11 Thread Jon Elson via cctalk

On 08/09/2019 11:05 PM, Douglas Taylor via cctech wrote:
I have a question about cable length - any electrical 
engineers in the house?


Connected a Qualstar 1260 tape drive to an Emulex TC02 
qbus tape controller in a pdp-11/53.  The interface is 
pertec with 2 50 pin cables.


When I use a pair of short flat ribbon cables, 18 and 30 
inches each, it works.  Under RT11 I can INIT, Copy, DUMP, 
do a Directory.


It doesn't work when I use a pair of 5 foot long flat 
ribbon cables.  Are they too long?  Do I need twisted pair 
type of cable?  Is it possibly a termination problem?


I have used cables about 20 feet long without trouble.  The 
2 50-pin cables is the Pertec formatted interface, which is 
really forgiving.  Does you drive have terminators in both 
ends of the cable (both at the TC02 end and the drive end)?
Now, I will mention that I have ONLY used twisted-pair 
ribbon cables with both flavors of interface, never straight 
ribbon cable.


Jon




Re: Alphaservers for free in Athabasca, Alberta

2019-08-06 Thread Jon Elson via cctalk

On 08/06/2019 03:42 AM, Dave Wade via cctalk wrote:

-Original Message-
From: cctalk  On Behalf Of Grant Taylor via
cctalk
Sent: 06 August 2019 04:25
To: cctalk@classiccmp.org
Subject: Re: Alphaservers for free in Athabasca, Alberta

On 8/5/19 8:40 PM, ben via cctalk wrote:

Now why could it not be a nice little PDP 11.

I thought that it could be if it was running emulation software.

Or was that more that the VAX-11 could emulate a PDP-11 up to a specific
version & hardware combination?  (Read: Did this functionality not get carried
forward to the Alphas?)


I think it went from the VAX fairly early in the model range. I don't believe 
that any of the MicroVax machines implemented this.
The VAX Architecture manual


The VAX 11/780 definitely had PDP-11 emulation, apparently 
in the microcode.  I'm kind of guessing the 750 and 730 also 
had this.  As far as I know, no later machines had hardware 
(microcode) emulation, and did it all by software.  It 
didn't take very long for DEC to recompile all the VMS 
utilities into native VAX executables.  I think we started 
with VMS 3.x and very quickly updated to a 4.1 VMS version.  
I was not aware of any PDP-11 code in them, but I did not 
look very closely.


Jon


Re: MULTIPROCESSING FOR THE IMPOVERISHED Part 1: a 6809 Uniprocessor

2019-08-03 Thread Jon Elson via cctalk

On 08/03/2019 02:06 PM, ben via cctalk wrote:


Many were not published. A friend built a TTL computer 
based on the PDP-8 but no details were published.
A field service tech at a company I once worked for built a 
16-bit computer that was a whole generation better than the 
12-bit machines that company made.  I know a few of them 
were built by others that worked there.  Most programs were 
entered through the front panel switches.
This was probably about 1976 or so.  Display was via an 
oscilloscope.


It was called the Mike Smith 1.  I've never found any 
reference to it online.


Jon


Re: IBM Series/1

2019-08-03 Thread Jon Elson via cctalk

On 08/02/2019 10:04 PM, ED SHARPE via cctalk wrote:

Was IBM Series/1 for process control?Ed#

I don't think it was necessarily DESIGNED for process 
control, it was a decent 16-bit mini.
But, it did get USED a lot for that application.  They were 
also used as interfaces from the IBM channel architecture to 
serial ports, where the 360/370's were hurt very badly by 
interrupt load.


Jon


Re: IBM Series/1

2019-08-03 Thread Jon Elson via cctalk

On 08/02/2019 09:32 PM, William Donzelli via cctalk wrote:

I have a pair, plus parts.

The hardware is excellent. They have fairly fast processors, and the
I/O capacity is great. Reliability is typical IBM.

The OS sucks balls. All the balls.

Commercially, they were not a success, despite being IBM's first
"open" system, in that they invited third party developers. It seems
like every S/1 I have ever seen has some CDC DNA in it, for some
reason. They ended up successful within IBM, once they found out they
were better comms boxes than the real mainframe boxes (3725, for
example). Some S/1s were built specifically for comms use on
mainframes (7171).


Yes, we used some Series/1 machines at Washington University 
for async dialup and local terminal use.  They had a channel 
interface, and this worked WAY better than even the Memorex 
1270, which still hit the system with a huge amount of 
interrupts.


We also got a disk development lab donated from IBM that was 
all run by S/1 systems.  They scrapped those and a bunch of 
the SLT/MST interface gear, and replaced it with modern stuff.


Jon


Re: IBM Series/1

2019-08-02 Thread Jon Elson via cctalk

On 08/02/2019 02:40 PM, Kevin Bowling via cctalk wrote:

Anyone have one of these?  I'd like to find a system, but images of
the OS media would be interesting.


I have some bits of several Series/1 systems, but no 
complete system at all.


Jon


Re: keycaps / switches for Tek 4006

2019-07-25 Thread Jon Elson via cctalk

On 07/25/2019 07:40 PM, Fritz Mueller via cctalk wrote:



On Jul 25, 2019, at 10:29 AM, Fritz Mueller  wrote:

I recently obtained a Tek 4006 from eBay as a repair/restoration project.  It 
is missing a few keycaps (both SHIFT keycaps, COPY, LINE FEED, and :/*).  In 
addition, one of the key mechanisms has a broken plunger.  Last, the little 
green paddle line power toggle power switch at the back appears to be broken.

After disassembly, I can see the keyboard assembly are marked "Cherry" and part 
number is B76-07AA.  I'm not enough of a keyboard wonk to know if these are still-mfg'd 
cherry key mechanisms?


I'm pretty sure Cherry is not still making these keyboards.  
But, there were a HELL of a lot of them made over the 
years.  There were several key switch styles in use - really 
cheap plunger that spreads the contacts apart when up, a 
magnet and reed switch type, a Hall sensor type, and maybe a 
capacitance type.  The key switches should be able to be 
replaced fairly easily.  Special keycaps will be a harder 
problem to solve.


Jon


Re: Scanning question (Is destruction of old tech docs a moral crime?)

2019-07-21 Thread Jon Elson via cctalk

On 07/21/2019 04:48 PM, ben via cctalk wrote:
It is not the DPI that is problem on some scans, but they 
used

a LOSSY format to store the data. JPEG IS NO!
Yes, ABSOLUTELY!  JPEG is designed for things that have 
smooth tones, like people and outdoor photographs.  It is 
horrible with anything that has sharp contrasts like letter 
outlines and line drawings.


Jon


Re: Scanning question (Is destruction of old tech docs a moral crime?)

2019-07-21 Thread Jon Elson via cctalk

On 07/21/2019 05:16 AM, Joseph S. Barrera III via cctalk wrote:

What dpi qualifies as not "crappy"? 300dpi? 400? 600?


Most of the text of these documents don't need super high 
resolution.  But, some contain hand-drawn schematics where 
an 11 x 17 original has been shrunk to 8.5 x 11" and 
hand-written signal labels and part types are VERY small.  
These need to be scanned at high resolution, with several 
retries while adjusting the image threshold to make things 
readable.
If they just scan the whole document at a reasonable 
resolution for text, the schematic will be very much harder 
to read.


Jon


Re: Recovering the ROM of an IBM 5100 using OCR (among other things)

2019-06-27 Thread Jon Elson via cctalk

On 06/27/2019 10:30 AM, Mark J. Blair via cctalk wrote:

I don't recall seeing one of those in either of the computer rooms I worked in 
as a student back in the late 1980s. I would love to get my hands on one (or 
make one?) now.


One brand of a liquid you put on the tape is MagnaSee.
If you google "magnetic tape viewer" they have pictures of 
what I think the earlier poster described.


Jon


Re: Recovering the ROM of an IBM 5100 using OCR (among other things)

2019-06-27 Thread Jon Elson via cctalk

On 06/27/2019 10:21 AM, Warner Losh via cctalk wrote:


Back when I got to school and I was hanging around the computer room on
campus (back when it was THE room on campus with computers), I saw this
half-dollar sized plastic fob on the desk and asked what it was for. The
on-staff operator took a mag tape off the rack, opened it up and set the
end of the tape on the table. She then took the fob and placed it on the
end of the tape and all the iron filings that were suspended in the liquid
inside the fob aligned to the magnetic fields of the tape. They used it to
tell the difference between 800, 1600 and 6250 bps tapes so they could
handle the tapes correctly
800 BPI tapes had no recording over the BOT marker.  1600, 
3200 and 6250 tapes had different tracks with a burst of 
ones and zeroes across the marker, that uniquely identified 
the density.
It had to be a really SIMPLE scheme as the drive itself (not 
the formatter) needed to detect this and set various 
circuits correctly, like read preamp gain and slicer threshold.


Jon


Re: OT: the end of Dyn DNS

2019-06-27 Thread Jon Elson via cctalk

On 06/26/2019 08:36 PM, Charles Dickman via cctalk wrote:

Now that Dyn has been absorbed by Oracle I need a new DNS service for my
vanity domain. I welcome suggestions for a replacement provider.

-chuck

I use Network Solutions, they are a bit expensive, though.  
Godaddy also provides that service.  Don't go with the 
cheapest, they could go out of business anytime.  My 
secondary DNS provider did just that, a month after I paid 
up for 2 years.


Jon


Re: unix developed on 11/20 with 20 on panel or machine that just said pdp/11?

2019-06-20 Thread Jon Elson via cctalk

On 06/20/2019 08:50 AM, Bill Gunshannon via cctalk wrote:


V6 will run on an LSI-11/02 with 28KW of memory.



28 KW is 56 KBytes, which is the max on most non-MMU CPUs.

Jon


Re: unix developed on 11/20 with 20 on panel or machine that just said pdp/11?

2019-06-19 Thread Jon Elson via cctalk

On 06/19/2019 08:23 PM, Bob Smith via cctalk wrote:

My recollection, Unix on the 11 started with the 20 but because of the
limited capabilties, it really was done on the /45.
The three rings or 3 execution levels were not supported on the
original machine.

MMU and expanded memory would be a great help in a 
multi-user system.  The original PDP-11 with 56 KB of memory 
was pretty limited.  Great for DOS-11 and RT-11, but more 
complex OS'es needed more resources.


Jon


Re: VAX ODT console fault

2019-06-12 Thread Jon Elson via cctalk

On 06/12/2019 03:41 AM, r.stricklin via cctalk wrote:

If I install a spare KA630-A and 8 MB memory board, I get a similar fault where 
chevrons repeat to infinity.
There are a couple possibilities.  If the baud rate is set 
wrong, the VAX could be replying to some gibberish at wrong 
baud rate, that causes the terminal to reply to that with 
something, and they endlessly jabber at each other.  Most 
terminals will send Xoff/Xon when a rapid burst of 
characters comes into the Rx port.  When misinterpreted by 
the VAX, that might cause it to send another burst of 
characters.  So, it could be entirely a software/setup issue.


Are you using a real terminal or a PC terminal program?  If 
a program, you might try a different one or try different 
comm settings.


As someone else mentioned, a leaking battery could have 
damaged traces or the baud selector switch on the panel 
interface module. Close inspection of that is strongly advised.


Jon




Re: What Makes a PDP-11/35 or 40 Tick?

2019-06-11 Thread Jon Elson via cctalk

On 06/11/2019 06:33 AM, Paul Birkel via cctalk wrote:

I wonder what the unlisted 20 ICs are for, and what they are?
I think the 23B are microcode ROMS, and the 441 seems to 
be clerical error.


Jon


Re: M7264 Troubleshooting

2019-06-07 Thread Jon Elson via cctalk

On 06/07/2019 06:19 PM, Mister PDP via cctalk wrote:

Wow, I wasn't aware that the ODT console needed memory to run. Checking on
my board, it looks like the 4kw was disabled. I plugged in my 32kw module
with my M8017-AA, and it fired right up to ODT without a hassle. Seems that
was the issue all along.


Oh, of course!  You can do very elementary checking of a 
switch-and-lights PDP-11 with no memory, but creating any 
sort of useful program that will run using only ROM and the 
8 registers would be VERY challenging.  I suspect you might 
be able to get it to print some text on the terminal, but 
not a whole lot more. Obviously, no way to call a subroutine 
without a stack.


Well, glad you found it!

Jon


Re: tape seals?

2019-06-07 Thread Jon Elson via cctalk

On 06/07/2019 01:06 PM, Chuck Guzis via cctalk wrote:

On 6/7/19 8:25 AM, Jon Elson via cctalk wrote:


My experience with them is that the seal bands are quite long-lasting,
but the black ends that snap in tend to crack after a while.  These
small parts could likely be reverse engineered and made on a 3D printer.

That's *definitely* not my experience.  I don't think I've ever had a
"hook" failure.

OK, my experience with 1/2" tape mostly ended about 20 years 
ago, but I STILL have one shelf of tapes in my shop, and ALL 
the seals are in excellent condition.  I have no idea why!  
(But, mine are in a metal rack, not hanging.)


But, we did have some where the separate black ends that 
formed the hanging hook and clamp broke.


Jon


Re: tape seals?

2019-06-07 Thread Jon Elson via cctalk

On 06/05/2019 06:05 PM, Stan Sieler via cctalk wrote:

Hi,

I think someone was looking for tape seals for 9 track tapes, a few weeks
ago.

If they can contact me offline, I have about 20 of varying sizes for
shipping cost or local pickup.
My experience with them is that the seal bands are quite 
long-lasting, but the black ends that snap in tend to crack 
after a while.  These small parts could likely be reverse 
engineered and made on a 3D printer.


Jon


Re: DEC R80 HDA details

2019-05-31 Thread Jon Elson via cctalk

On 05/30/2019 10:56 PM, Tony Duell via cctalk wrote:
[1] I feel DEC got one thing wrong here. The preamplifier 
ICs are inside the HDA and thus can't be replaced.
This was pretty common practice in a number of drives from 
that period.  Now, it is common for the read amps to be on 
the individual hear arms, to get them closer to the heads.


Jon


Re: DEC R80 HDA details

2019-05-31 Thread Jon Elson via cctalk

On 05/30/2019 02:20 PM, shad via cctalk wrote:

Hello,
I'm in the process of cleaning and hopefully restore to operation of a DEC
R80.
The unit has some minor sign of corrosion, however it's VERY dirty, even
inside the hood.
The filters are obviously to be removed and replaced, as they are
disintegrating.
Also foam parts between the boards must be replaced.
Aside from obvious parts, there's something that should be replaced /
cleaned inside the HDA (foams, filters or rubbers), which could damage the
disk permanently in case it's turned on after decades if not "cured" before?
Anybody has some good pictures of the HDA inside, after cover removal?

I don't think this is a field procedure.  Definitely, way 
back around 1980 or so, they had some bum adhesive that held 
the internal filter in the RA80 and RA82 HDAs, as I recall, 
and they had to replace all HDAs in the field, over time.  
They had some scheme where the oldest HDAs were replaced 
first, as the adhesive degraded over time, so they knew they 
had a couple years since new before the problem would 
occur.  It was a BIG expense for DEC.


Presumably, all of these HDAs (that were under maintenance 
contract) that had the bad adhesive in them were replaced 
years ago.  As far as I remember, there IS no removable 
cover on those HDAs, they were hermetically sealed except 
for a tiny, filtered, pressure relief vent.
I think the procedure to update those HDAs was a pretty 
involved disassembly.



Jon


Re: Process accounting - did anyone ever use it?

2019-05-31 Thread Jon Elson via cctalk
From: "Grant Taylor via cctalk"  To: 
"cctalk mailing list" 

Sent: Thursday, May 30, 2019 1:30:51 PM
Subject: Process accounting - did anyone ever use it?

>(Credit the Quotas thread for prompting this.)
>Did anyone ever use process accounting? Did they actually 
bill departments
>(funny money)? I was always intrigued by process 
accounting, but never had a use
>for it myself. I guess I can thank process accounting for 
causing the discrepancy
>that Cliff Stole tracked down that became The Cuckoo's 
Egg. :-)
Not exactly sure what you are asking about, but if you mean 
run time accounting to bill users, then we did this on one 
system I managed. We depended on the other department's 
contributions to fund the total expenses of the machine 
(purchase price plus software and hardware maintenance 
contracts), which were pretty expensive on a VAX 11/780.
Somewhere, deep in the bowels of the University's accounting 
department, they transferred several thousand $ of "real 
money" per month to our account.  The bill varied depending 
on how much CPU time they used.  I wrote some DCL scripts to 
roll over the accounting file daily, and then break it down 
by user and compute a $ amount based on a formula that had 
been agreed upon.


It is Clifford Stoll, IIRC.

Jon


Re: M7264 Troubleshooting

2019-05-26 Thread Jon Elson via cctalk

On 05/26/2019 10:44 AM, Jon Elson via cctalk wrote:

On 05/26/2019 12:13 AM, Mister PDP via cctalk wrote:
Ok, small update. My M8043 (DLV11-J) just arrived today. 
It seemed in good
condition so I confirmed it was set up correctly (9.6k 
baud and console on
J3), built a serial cable from the information provided 
on gunkies, and put
it into my system. Sadly, it behaves exactly how it did 
with the M8017. No
output, no activity on the BRPLY line. I have a hard time 
imagining that
both my M8017 and my M8043 are bad, but it could still be 
possible.



Well, if just ONE address line driver on the CPU has gone 
bad (or a short in the backplane) it could prevent the DLV 
from recognizing the address.  If there are any other 
boards in the system, take them out.  Maybe even the 
memory boards, and try to read/write the DLV addrsss from 
the console.  (Oh, maybe that's the problem, you don't 
have the full programmer's console on this machine.)


Oh, DLV means Q-bus, so there isn't much choice EXCEPT 
serial console, is there?
Yeah, when the serial console doesn't work, you've got a 
problem. You could check each addr/data line to see that it 
wiggles.  If it doesn't wiggle, then you can see if the 
state it is in makes sense. Obviously, somewhere in the 
serial console routine, it should be addressing the serial 
console, so every line should at some point be in the state 
to select the console CSR.
A logic analyzer set up to read out the bus would be a good 
tool at this point.


Jon


Re: M7264 Troubleshooting

2019-05-26 Thread Jon Elson via cctalk

On 05/26/2019 12:13 AM, Mister PDP via cctalk wrote:

Ok, small update. My M8043 (DLV11-J) just arrived today. It seemed in good
condition so I confirmed it was set up correctly (9.6k baud and console on
J3), built a serial cable from the information provided on gunkies, and put
it into my system. Sadly, it behaves exactly how it did with the M8017. No
output, no activity on the BRPLY line. I have a hard time imagining that
both my M8017 and my M8043 are bad, but it could still be possible.


Well, if just ONE address line driver on the CPU has gone 
bad (or a short in the backplane) it could prevent the DLV 
from recognizing the address.  If there are any other boards 
in the system, take them out.  Maybe even the memory boards, 
and try to read/write the DLV addrsss from the console.  
(Oh, maybe that's the problem, you don't have the full 
programmer's console on this machine.)


Jon


Re: IBM 1620 manuals

2019-05-25 Thread Jon Elson via cctalk

On 05/13/2019 10:57 PM, Jon Elson via cctalk wrote:
I just discovered a binder with 2 IBM 1620 manuals.  A 
quick check shows bitsavers has these and newer editions 
of them.


So, does anybody want :

IBM 1620 Central Processing Unit, Model 2  (Form A26-5781-1)

and

IBM 1620 Monitor II System Reference Manual (Form C26-5774-0)

Jon

OK, since the mysterious "Steve" who actually HAS a 1620 
apparently can't be contacted, anybody else have a 1620, or 
know somebody who does?  Or, has a significant collection

of 1620 items?

These manuals, or newer editions, are already on bitsavers, 
so there's nothing new there.


Otherwise they go to the person who contacted me first on 
5/13. (I'm just seeing if there's anybody who actually NEEDS 
these before giving them to somebody who just "wants" them.)


 Jon


Re: M7264 Troubleshooting

2019-05-22 Thread Jon Elson via cctalk

On 05/22/2019 05:04 PM, Noel Chiappa via cctalk wrote:

 > On the LSI-11/2, with the machine stopped, 'run' was off, and the
 > output on AF1/AH1 was always high (i.e. not asserted).
 > I don't have any guesses as to what the behaviour of yours is about.

Hah! Eureka! I had a brainwave, and decided to look at my machine with
the serial console board pulled out!

I then get the exact same behaviour on SRUN as you're seeing - a very brief
spike every so often (about every 25 usec, here).

Yes, this is most likely a bus timeout as the console 
firmware is polling the serial module, and that module is 
apparently not acknowledging the request.


Jon


Re: Pleas ID this IBM system....

2019-05-21 Thread Jon Elson via cctalk

On 05/21/2019 04:33 PM, Chuck Guzis via cctalk wrote:

How well sealed were the raised floors?
Not at all.  They were 2 foot squares sitting on adjustable 
pillars.  Each pillar supported 4 tiles where they all met 
at the corners.  You could easily slip a punch card (or 
credit card) between most of the tiles.  Anything poured on 
the floor would run down between the tiles.


Jon


Re: apollo psa test point adaptor

2019-05-21 Thread Jon Elson via cctalk

On 05/20/2019 05:38 PM, Carl Claunch via cctalk wrote:

On 05/19/2019 09:46 AM, Jon Elson via cctalk wrote:

There's a switch labeled "IRIG" which stands for Inter Range
Instrumentation Group, and refers to a standard for
   telemetry encoding.  There is a standard for time code, a
   standard for modulating analog signas onto a bunch of FM
   carriers, and a standard for multiplexing several analog
   signals onto one FM carrier.

In this case IRIG stands for Inertial Reference Integrating Gyroscope, one
of three inside the Intertial Measurement Unit of the spacecraft.
Good GRIEF!  Clashing acronyms.  And, NASA certainly knew 
about the other IRIG, as they used IRIG standards on a lot 
of telemetry and radar systems.


Jon


Re: apollo psa test point adaptor

2019-05-19 Thread Jon Elson via cctalk

On 05/18/2019 10:08 PM, Adrian Stoness via cctalk wrote:

anyone know where i could find manual or drawings on this im up in northern
manitoba canada picked it up at a rr auction to experiment with as a audio
interface not sure if the jacks on the side are the weird pins nasa had or
another standard i can find?

https://www.flickr.com/photos/1ajs/albums/72157705166193482

There's a switch labeled "IRIG" which stands for Inter Range 
Instrumentation Group, and refers to a standard for 
telemetry encoding.  There is a standard for time code, a 
standard for modulating analog signas onto a bunch of FM 
carriers, and a standard for multiplexing several analog 
signals onto one FM carrier.


Apollo documents are probably VERY hard to come by these days.

Jon


IBM 1620 manuals

2019-05-13 Thread Jon Elson via cctalk
I just discovered a binder with 2 IBM 1620 manuals.  A quick 
check shows bitsavers has these and newer editions of them.


So, does anybody want :

IBM 1620 Central Processing Unit, Model 2  (Form A26-5781-1)

and

IBM 1620 Monitor II System Reference Manual (Form C26-5774-0)

Jon


Re: How were 32-bit minis built in the 70s/80?

2019-05-12 Thread Jon Elson via cctalk

On 05/12/2019 10:34 AM, Tony Aiuto via cctalk wrote:


Perdue also had Gorge Goble. https://en.wikipedia.org/wiki/George_H._Goble,
who was a character.

INDEED!  I sold him a scrap refrigeration compressor which 
he used to prove that his proprietary mix of refrigerants 
would return the oil to the compressor over a variety of 
conditions.


He developed several replacements for the banned R-12, and 
got patents on them.  But, I don't think he ever made any 
money with that, the HUGE chemical giants saw to that.


Jon


Re: How were 32-bit minis built in the 70s/80?

2019-05-11 Thread Jon Elson via cctalk

On 05/11/2019 06:14 PM, Warren Toomey via cctalk wrote:

I'm building my own 8-bit CPU from TTL chips, and this caused me to think:
how were 32-bit minis built in the late 70s and early 80s? In particular,
how was the ALU built? I know about the 74181 4-bit ALU, and I know (from
reading A Soul of a New Machine) that PALs were also used.

Did companies get custom chips fabricated, or was it all off-the-shelf chips
with a few PALs sprinkled in?


There were also the AMD2901, 2903, 29203 family of bit-slice 
components, with the 2910 sequencer.  I built a 32-bit basic 
microengine in about 1982, but the software development 
effort eventually led me to stop work on it.  I was planning 
to implement the IBM 360 instruction set, with extensions, 
as it was very easy to implement with microcode.


See http://pico-systems.com/stories/1982.html  for some 
description and photos.


Apollo built some machines which I think were programmed at 
the microinstruction level, without microcode, using 2903's, 
I think.


The VAX 11/780 used 74S181 ALU chips, I think.  There were 
not all that many 32-bit minis.
I can think of Interdata 7/32 and 8/32 models that were 
32-bit.  SEL also made a 32-bit mini.
The VAX 11/780 was completely done with off-the-shelf ICs.  
Later VAXes went to semi-custom ICs, and the MicroVAX line 
used full-custom ICs.  I suspect many other makers were so 
small, they could only use off the shelf parts.


Jon


Re: Looking for DEC M7264-CB Troubleshooting Documentation

2019-05-09 Thread Jon Elson via cctalk

On 05/09/2019 11:57 AM, Mister PDP via cctalk wrote:

Hello,

As part of my H11A project, I am trying to debug my M7264-CB LSI-11 CPU
module. When powered on, the CPU does not respond to the Run/Halt switch
either on the front panel or via the console. I found engineering
schematics for the M7264 online, but I was wondering if any in depth
troubleshooting material existed online (Logic probe points, debugging
steps, etc...).


Well, first thing to check is that the bus is properly 
terminated, and that memory requests are being properly 
acknowledged.


Jon


Re: VMS versions

2019-05-06 Thread Jon Elson via cctalk

On 05/06/2019 10:55 AM, Ray Jewhurst via cctalk wrote:

Does anyone know if there is a comprehensive list of changes from version
to version for VMS? Wikipedia's list only shows the models that were
introduced and I am more interested in the evolution of features. If anyone
knows a website that shows this it would be much appreciated.


Wow!  There were revision notes (is that the correct term?) 
that accompanied each new version, telling the major things 
that had changed.  If you can find the manuals that went 
with the versions, they had this revision info, and then 
notes on how to install or update a system.


Jon


Re: Service for converting CD-ROMs into ISO files?

2019-05-04 Thread Jon Elson via cctalk

On 05/04/2019 01:38 PM, ben via cctalk wrote:

On 5/4/2019 8:15 AM, Paul Koning via cctalk wrote:
thought a CD-ROM (data CD) *is* an ISO image.  So I would 
expect all you need to do is make an image copy of the 
disk.  On Unix systems that's trivial, just use the "dd" 
command to copy /dev/whatever to myfile.iso.
Or, better than that, just put it in just about any computer 
and read the files, copy to a directory on hard drive, etc.  
The ISO-9660 format was designed to be OS-agnostic, so you 
can read the files on any OS.


Jon


Re: Old CE manuals

2019-05-04 Thread Jon Elson via cctalk

On 05/04/2019 01:21 PM, Donald via cctalk wrote:

Still cleaning out for Nevada move.

  


http://www.myimagecollection.com/cemanuals/

  


Last 2 are interesting. 2075 Processing Unit and some Russian machine
EC4001.  Number sounds familiar from my eBay sojourns.

  


Available for cost of Media Mail shipping. These buggers are heavy.  As last
time, all or nothing.


WOW, the 2075 is the 360/75, one of the higher-end models.  
The 2821 is the unit record controller (card read/punch and 
printer), I'm pretty sure bitsavers has that.  The 4341 is 
one of the office credenza style CPUs, and was a VERY good 
deal in terms of price/performance.


Jon


Re: Unknown 1970 Tapedrive

2019-04-29 Thread Jon Elson via cctalk

On 04/29/2019 02:25 PM, jos via cctalk wrote:
Was given a tapedrive in rather bad condition, but it has 
no manufacturers name on it.


Pics  on ftp://ftp.dreesen.ch/Tapedrive


Anyone recognizes this ? The paddle PCB says "paddle 
board, 7/9 level tape handler."


Not even sure if it is a computer tape drive or an 
instrument  / data logger...



I'm pretty sure it is a digital/computer drive.  It really 
looks military to me.  Possibly from some test gear.


Jon


Re: Nat Semi 16032 info discovered

2019-04-29 Thread Jon Elson via cctalk

On 04/29/2019 02:23 PM, Al Kossow via cctalk wrote:


On 4/29/19 9:30 AM, Jon Elson via cctalk wrote:

Back in 1984 I had cloned a Logical Microcomputer Co. Genix system based on the 
Nat. Semi. 16032 chip set.  I had a dd
dump of the distribution on floppies, but that was unreadable.
I just found a binder with about an inch of fanfold printouts of all the device 
drivers, low-level system routines, boot
loaders, etc in c source format.

These were printed on my Honeywell "big iron" drum printer with a funny 
character set, so many of the ASCII 96
characters are printed using overprints.  Like, { shows as a < overprinted with 
(.
So, it might be tricky to scan and OCR it without training the OCR. Not sure 
anybody would be interested in it, anyway.

Jon

I have an image of the Genix source tape.
Will try to dig it up.



Oh, OK, then maybe there's no need to scan this stuff.

Jon


Re: Excessive amount of time in interrupt stack mode

2019-04-29 Thread Jon Elson via cctalk
On 04/29/2019 12:11 PM, Carlos E Murillo-Sanchez via cctalk 
wrote:


Dear ccmp'ers:

For a while now, I noticed that my vaxstation 4000/60 with 
OpenVMS 7.2 had become sluggish, but I had not had the 
time to investigate the problem.   The system is mostly 
idle, RAM is mostly free (there's 32mb), there is almost 
no paging, but the CPU is spending upwards of 70% of the 
time in the interrupt stack mode. Currently, I am running 
it headless because I have not had the time to fix the 
monitor (it still has the framebuffer inside, but this 
sluggishness issue was present before with the monitor 
attached).  I have read that this can be caused by "faulty 
i/o devices that interrupt the cpu continuously".  What 
else can be done to locate the source of the problem?

Check for disk fragmentation?

Jon


Re: Nat Semi 16032 info discovered

2019-04-29 Thread Jon Elson via cctalk

On 04/29/2019 12:07 PM, Steven M Jones via cctalk wrote:



PS - If anybody's got ns32k hardware, I'm interested... ;)

I have a complete, wire-wrapped clone of the Logical 
Microcomputer Co. 16032 system, except for memory and the 
MFM disk.  So, that's the CPU on Multibus-I, a Taisho disk 
controller, and a board with 5 2561 (I think) UARTs for 
serial comms.


I ran it for about 18 months, I think, until I had the 
incredible fortune to be able to buy a microVAX-II.  The 
16032 with Multibus memory and MMU turned on was just 
glacially slow.
It took several minutes for emacs to load, I'm not 
exaggerating. Maybe I didn't have enough memory on it, and 
of course an MFM disk is kind of slow, too.


Jon



Re: Greetings

2019-04-29 Thread Jon Elson via cctalk

On 04/29/2019 06:47 AM, allison via cctech wrote:

On 04/28/2019 09:28 PM, Grant Taylor via cctech wrote:

On 4/28/19 6:27 PM, Ray Jewhurst wrote:

I already have a Hobbyist License.  I am just interested in
experimenting with different OSes and different versions of OSes.

ACK

I don't know what VAX hardware VMS 1.5 supported, what VAX hardware
that Simh supports, or what the overlap is between the two.

There's a reasonable chance that someone will chime in with experience.




You are limited to what the VAX-11/780 system had for peripherals and
typically under 8MB ram (it maxed at 16mb).
Well, for command-line computing (well, this IS the classic 
computing list) you can do a lot.
Our first 11/780 had half a megabyte of memory.  Friday 
afternoon one memory board went bad, and I pulled it out.  A 
user group ran a gigantic batch job of mechanical analysis 
over the weekend on 256 K!  I was amazed, I really thought 
it would thrash itself to death on that.


I ran a microVAX-II at home on one meg for years.

But, I never experienced VMS before about version 3.4, I 
think.  I'd really hate to run any VMS that didn't have 
loadable device drivers.  Doing the brute force sysgens was 
so RSX-11 ish.
I think VMS 1.5 still had a bunch of utilities running in 
PDP-11 emulation.


Jon



Nat Semi 16032 info discovered

2019-04-29 Thread Jon Elson via cctalk
Back in 1984 I had cloned a Logical Microcomputer Co. Genix 
system based on the Nat. Semi. 16032 chip set.  I had a dd 
dump of the distribution on floppies, but that was unreadable.
I just found a binder with about an inch of fanfold 
printouts of all the device drivers, low-level system 
routines, boot loaders, etc in c source format.


These were printed on my Honeywell "big iron" drum printer 
with a funny character set, so many of the ASCII 96 
characters are printed using overprints.  Like, { shows as a 
< overprinted with (.
So, it might be tricky to scan and OCR it without training 
the OCR. Not sure anybody would be interested in it, anyway.


Jon


Re: Televideo 925 character rom dump

2019-04-23 Thread Jon Elson via cctalk

On 04/23/2019 02:23 AM, Josh Dersch via cctalk wrote:

Hi all --

I'm working on a Televideo 925 terminal with a few problems, one of which
is a bad character generator ROM, (a MOS 2332).  Does anyone have a dump of
this already, or have a working 925 they'd be able to dump the ROM from?


Is the ROM totally bad, or just losing a few bits here and 
there? If the latter, you could probably read it out, figure 
out how the rows, columns and characters are mapped, and fix it.


Jon


Re: Plane of core memory

2019-04-18 Thread Jon Elson via cctalk

On 04/18/2019 03:15 PM, Noel Chiappa via cctalk wrote:

 > From: Jon Elson

 > As soon as somebody figured out that you could combine the sense and
 > inhibit wires, everybody immediately went to 3-wire planes.

I"m suprised the idea wasn't patented. Or maybe it was, and they made the
license widely available at modest terms?


I was thinking the same thing, but can't find any references 
to who invented it.  it certainly sounds like the sort of 
thing to get a patent on.


Point of interest, my freshman advisor was Bill Papian, who 
was Jay W. Forrester's grad student when he invented 
coincident-current core memory.


Jon


Re: Plane of core memory

2019-04-18 Thread Jon Elson via cctalk

On 04/18/2019 04:49 AM, Brent Hilpert via cctalk wrote:
It's a 4-wire 3D planar array. By topology and 
construction I would guess it date it from the 60s.
Make that EARLY '60s.  As soon as somebody figured out that 
you could combine the sense and inhibit wires, everybody 
immediately went to 3-wire planes.


Jon


Re: Pleas ID this IBM system....

2019-04-17 Thread Jon Elson via cctalk

On 04/17/2019 02:30 AM, Christian Corti via cctalk wrote:

On Tue, 16 Apr 2019, William Donzelli wrote:
The 3125 would likely be near impossible to get running 
without a full

set of docs.


I think I could have access to the 3125 docs (MLM, CTM, 
ALD etc.). At least I know where they are.


Does the 3125 use a motor-generator set, like the larger 
models?  Do you have the right power to run the MG?  I know 
the MGs on the 3145 were oversized, so maybe the same unit 
could also run nthe 3158, and demanded an INSANE current 
surge when spinning up.  Also, the running current, even at 
idle, was pretty crazy, somewhere around 60 A at 208 V 3-phase.


Jon


Re: ATEX PDP-11 For Sale in Houston

2019-04-16 Thread Jon Elson via cctalk

On 04/15/2019 12:08 PM, Thomas Raguso via cctalk wrote:

I am selling an Atex PDP-11/34. The computer has: J11 CPU, 11 MB RAM, 2
BA11-LE expansion chassis, a second backplane, an SMD disk controller and
LAN hardware.



11 MB ram on a PDP-11?  Is that possible?

Also, was the J11 used in the 11/34?  Wasn't the /34 all TTL?

Jon


Re: Interesting article in Spectrum about IBM's System/360

2019-04-13 Thread Jon Elson via cctalk

On 04/13/2019 09:11 AM, Jay Jaeger via cctalk wrote:
For example, the IBM 7010 was an IBM 1410 done up in 7000 
series technology (and was a compatible super-set of the 
1410 and, via a toggle switch, the 1401). It had no 
architectural relationship with the 7090/7094, nor did the 
7070 or 7080, near as I can tell.
Yes, the 14xx were character-based decimal machines.  The 
7070 was a word-based decimal machine aimed at the business 
market.  The 709x were word-based binary machines.


Jon


Re: Interesting article in Spectrum about IBM's System/360

2019-04-12 Thread Jon Elson via cctalk

On 04/12/2019 04:14 PM, Chuck Guzis via cctalk wrote:

On 4/12/19 11:15 AM, Eric Smith via cctalk wrote:

The article says:

Poughkeepsie’s engineers were close to completing work on a set of four

computers known as the 8000s that were compatible with the 7000s.

My tendency has been to consider 7000 xeries machines as transistorized
700 series.  Certainly that applies in the case of the 7090.

Well, to an extent.  Yes, the 709x was able to run 709 
programs, and had a few extensions.
But, really, the hardware was VERY advanced.  The 7094 was a 
real lightning fast machine, for the technology available at 
the time. In fact, it was faster than most of the 360 line 
that replaced it. But, the funny thing was, it didn't 
multitask well, and so you could only run one program at a 
time.  And, spooling input and output to tapes slowed it 
badly (although not as badly as reading cards and printing 
directly would have).  So, while fast, it didn't run 
efficiently.
Slower 360's could keep busy by multiprocessing, and thus 
get more work done.


Jon


Re: Interesting article in Spectrum about IBM's System/360

2019-04-12 Thread Jon Elson via cctalk
On 04/12/2019 12:41 PM, Carlos E Murillo-Sanchez via cctalk 
wrote:

Building the System/360 Mainframe Nearly Destroyed IBM

https://spectrum.ieee.org/tech-history/silicon-revolution/building-the-system360-mainframe-nearly-destroyed-ibm 





Yup, they bet the company on a new product.  it was a VERY 
well thought-out bet, but still a big reach.  One area they 
really made a mistake on was software.  They designed a 
really ambitious OS (OS/360 MFT) and then an even more 
ambitious version (OS/360 MVT) on a poorly thought-out 
timeline.  Fred Brooks actually had a nervous breakdown over 
it, and maybe some other guys, too.  Fred Brooks' "The 
mythical man month" is just too short, and doesn't have 
enough actual anecdotes, but is a good read anyway.  At the 
time he wrote it, there were probably a bunch of stories 
that he couldn't yet tell.


Also, the hardware was a huge leap.  IBM went from building 
computers with all purchased components on single-sided 
paper-phenolic PC boards to making their own transistors and 
diodes and packaging them on little ceramic hybrid modules, 
and then putting those on 4-layer PC boards.  They pioneered 
a LOT of packaging technology on the 360.  The developed 
flip-chip bump-bonding of semiconductors, and were doing 
this almost 20 years before anybody else were doing this.  
But, of course, there would be growing pains with such 
development.  The entire state of New York was a bustling 
beehive of computer manufacturing.  They made disk and tape 
drives, printers, hand-assembled close to 20,000 mainframe 
CPUs plus all the controllers and memory, between 1965 and 
1969. Totally mind boggling!


Jon


Re: Daisywhell typewriter emulating a TTY

2019-04-10 Thread Jon Elson via cctalk

On 04/10/2019 03:38 AM, GerardCJAT via cctalk wrote:

I would like to emulate a TTY, using a daisywheel typewriter.

Well, there are Qume and Diablo.  Diablo was bought by 
Xerox, so some of them carry that label.
Most of the stand-alone versions had serial (RS-232) ASCII 
interface.


Jon


Re: Tape Storage Rack WAS: RE: 1/2" tape storage.

2019-04-09 Thread Jon Elson via cctalk

On 04/08/2019 11:34 PM, Ali via cctalk wrote:

While on the subject of tape storage anyone know if it is still possible to get 
desktop/table top wire bins to hold tapes in canisters and/or reels? Not that I 
have that many tapes or anything like that. This would be more for display 
purposes than anything else.


Yikes, I doubt anybody has manufactured these in the last 30 
years. I have one, but don't want to get rid of it until I 
scrap all my old tapes.


Jon


Re: %20Storage%20for%201/2"%20open%20reel%20tape

2019-04-09 Thread Jon Elson via cctalk

On 04/08/2019 10:26 PM, Adrian Stoness via cctalk wrote:

whats with the weird tag on this thread?


%20 is an escaped form of the space character.  Some mail 
programs escape all control characters, or even anything 
like {} ~.


Jon


Re: Pleas ID this IBM system....

2019-04-08 Thread Jon Elson via cctalk

On 04/08/2019 06:10 PM, Tom Gardner via cctalk wrote:

FWIW the tape drive is an IBM 2315 announced April 16, 1965 
  for use on 
low end S/360s.  Here is a brochure 
  as well as manuals at 
http://www.bitsavers.org/pdf/ibm/2415/


So, is that a capstan and pinch roller drive?  I'd kind of 
guess so, if announced in 1965.
(for future readers, 2315 is apparently a typo, 2415 would 
fit in with 24xx models being tape drives, 23xx was for disks.)


Jon


Re: Pleas ID this IBM system....

2019-04-06 Thread Jon Elson via cctalk

On 04/06/2019 01:09 PM, Al Kossow via cctalk wrote:

Hopefully LCM can go after this to flesh out their peripherals
It looks like a nice set of disks and tapes, hopefully the 360-era
disk and tape channel controllers are there too

On 4/6/19 7:04 AM, jos via cctalk wrote:


https://www.ebay.de/itm/seltene-Anlage-Puma-Computer-IBM-2020/202646831828?hash=item2f2eb142d4:g:izoAAOSwhV1cpw


Oh, yeah, I did NOT recognize those dual tape drives with 
horizontal vacuum columns.

Obviously real IBM, but I've never seen them before.

Jon


Re: Pleas ID this IBM system....

2019-04-06 Thread Jon Elson via cctalk

On 04/06/2019 01:09 PM, Al Kossow via cctalk wrote:

Hopefully LCM can go after this to flesh out their peripherals
It looks like a nice set of disks and tapes, hopefully the 360-era
disk and tape channel controllers are there too


Nope, not on a model 20.  The 360/20 did not have channels, 
it had specific I/O controllers built into the CPU backplane 
for disk, tape, cards and printers, and an optional one-line 
serial interface.
So, all peripherals plugged into their specific controller 
in the /20, there were no external control units like a 
2821, 2803, 2314, etc.


The 360/20 was a VERY limited machine, max of 32KB of 
memory, but most had a LOT less.
There was RPG for it, but most were used for off-line 
spooling of cards and printing, or RJE systems.


If there is a 370 there, possibly there could be control 
units for that machine in the collection.


Jon


Re: Not DEC related but still hoping for some help: Problems w/ LJ 4+ Printer

2019-04-03 Thread Jon Elson via cctalk

On 04/03/2019 03:24 AM, Ali via cctalk wrote:

Is the fuser roller warming up properly?  Or, is it the
corona supply is having trouble coming up to voltage?  You
should pull the bottom of the printer apart and thoroughly
clean the PC board on both sides.  If you have never done
this, it will be a HUGE BLACK MESS with spilled toner dust -
don't ask how I know this!


Jon,

Based on the info coming through on the list a "cold" fuser would produce
toner that would wipe off/flake off of the printed sheet. This is not
happening in my case so I am guessing the fuser is getting hot "enough".

OK, sounds right.

The
current hive thinking seems to be toward the corona wire - specifically
failing caps in HV needing time to warm up to specs before working properly.


First, since you have not checked with another cartridge, is 
to examine the corona wires and/or "combs" on the cart.  
Sometimes the wires break at one end.  Also, toner spills 
could short it out, I've had that before.  Bent contacts on 
the cart where it connects the HV to the printer could also 
be making bad/no contact.


But, the caps could be it, the symptom where it starts 
working after warming up does indicate weak caps.


Jon


Re: Not DEC related but still hoping for some help: Problems w/ LJ 4+ Printer

2019-04-03 Thread Jon Elson via cctalk

On 04/03/2019 03:24 AM, Ali via cctalk wrote:
Thanks for that tidbit. I didn't realize that a HV failure 
would not produce any error codes. If that is the case 
looks like I am recapping a board. Out of curiosity what 
symptoms were you getting?


Nope, I think there is some sort of self-check on the fuser 
thermistors, but the corona supply is open-loop on most 
printers. There is also a self-check on the laser, as the 
beam has to hit a sensor to start the timing of the pixels.  
So a failed laser or polygon motor will cause an error.


Good luck with it!

Jon


Re: Not DEC related but still hoping for some help: Problems w/ LJ 4+ Printer

2019-04-02 Thread Jon Elson via cctalk

On 04/02/2019 02:56 PM, Ali via cctalk wrote:

I rescued a LaserJet 4+ printer that I have been trying to restore.
Initially everything seemed ok and it seemed as if there may be just a bit
of an issue with paper pickup which I attributed to old paper in the tray.

However, soon I started getting the accordion paper jam which led me to
replacing all the rollers including the transfer roller. Now the paper flows
freely! However, I am having a new problem with printing. When I print, the
first 5-10 pages initially come out blank. The printer does not produce any
errors or error codes. The blank pages are warm (not hot though) as expected
out of a LJ.

After closer inspection it seems that the pages are printed SUPER light and
gradually get darker the more I use the printer continuously. Eventually the
printer starts printing continuous crisp black pages like new. This is a
whole page phenomenon (i.e. not gaps, missing areas, etc.).


Is the fuser roller warming up properly?  Or, is it the 
corona supply is having trouble coming up to voltage?  You 
should pull the bottom of the printer apart and thoroughly 
clean the PC board on both sides.  If you have never done 
this, it will be a HUGE BLACK MESS with spilled toner dust - 
don't ask how I know this!


I have a 5M, but I think the mechanism is the same.

Jon


Re: Model 40 Re: IBM 360 Model 50 information?

2019-04-02 Thread Jon Elson via cctalk

On 04/02/2019 09:49 AM, Al Kossow via cctalk wrote:


On 4/1/19 7:45 PM, Bill Degnan via cctalk wrote:

can you show me an example?  Long shot but I can at least check to see if I
have any in my 360 docs.  I have mostly programming manuals and general
hardware docs but a stray ALD may be present.

ALDs are 11x17, and are marked with the product number on the spine of the 
n-ring binder
Not only that, they are marked with the machine serial 
number, and are specific to that machine.
So, any ECOs, or hardware options present in that machine 
will be shown on the schematics.
There will be several other manuals in the set that are not 
specifically "ALD"s, but are part of the set, such as 
microcode listings and FLT (Fault Location Test) manuals 
that reflect ECOs and options.


Jon


Re: Model 40 Re: IBM 360 Model 50 information?

2019-04-02 Thread Jon Elson via cctalk

On 04/01/2019 09:45 PM, Bill Degnan via cctalk wrote:

can you show me an example?

I think this may actually be a section of the "ALD"s for a 
model /50:


http://www.bitsavers.org/pdf/ibm/360/fe/2050/2050_Vol18_Sep72.pdf

And, this one has pretty detailed info on the microcode 
flow, listing of operations, etc.

(This may be what the OP was already working with.)

http://www.bitsavers.org/pdf/ibm/360/fe/2050/Z22-2833-R_2050_Processing_Unit_Field_Engineering_Diagram_Manual_Jul66.pdf


This whole area of bitsavers is well hidden, but has a 
wealth of hardware information:


http://www.bitsavers.org/pdf/ibm/360/fe/

Jon


Re: H786 power supply help wanted

2019-03-30 Thread Jon Elson via cctalk

On 03/30/2019 07:50 PM, Charles via cctalk wrote:

Update: I removed the H786 from the chassis, and set it up on the workbench 
with loads on the +5 and +12.
No output. 320V across the half-bridge, but no +12 Startup. Found I had 
forgotten to put a cliplead to the primary of the startup transformer.
Turned it on and it works... 5 and 12 volts into 1 ohm and 4.7 ohm 
respectively. WTF.

So I disconnected the PC supply, put the H786 back in, and it fired right up 
(including the real-time clock) and I ran it for half an hour.
Go figure. Ain’t classic computers fun sometimes...




Connectors, always flaky connectors!

Jon


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