Re: PDP-8/a wire-to-board connector for power?

[Brian Walenz via cctalk]

Awesome, thanks!  I missed that in my scan of the Mouser catalog.

https://www.mouser.com/ProductDetail/TE-Connectivity/1-480270-0/

$0.86 for the connector, $160 for the crimper.

b


On Fri, Nov 3, 2017 at 9:36 PM, Chuck Guzis via cctech <
cct...@classiccmp.org> wrote:

> On 11/03/2017 05:40 PM, Brian Walenz via cctech wrote:
> > I'm assembling a PDP-8/a from a pile of parts, but I'm missing the entire
> > AC power entry assembly, as shown in
> > http://www.retrotechnology.com/restore/8a_trans_gnd0.jpg.  Does anyone
> know
> > what the 6-pin connector is?  Even better, does anyone have an extra
> > assembly?
>
> That connector is still being made!  It's an AMP Mate-n-lock:
>
> http://www.te.com/usa-en/product-1-480270-0.html
>
> Well, okay, it's not "Amp" anymore, Amp's been eaten.
>
> --Chuck
>
>

PDP-8/a wire-to-board connector for power?

[Brian Walenz via cctalk]

I'm assembling a PDP-8/a from a pile of parts, but I'm missing the entire
AC power entry assembly, as shown in
http://www.retrotechnology.com/restore/8a_trans_gnd0.jpg.  Does anyone know
what the 6-pin connector is?  Even better, does anyone have an extra
assembly?

Thanks to Herb Johnson for the 8/a repair write ups (
http://www.retrotechnology.com/restore/8a_repairs.html) and pictures.  Very
helpful!

bri

Re: Why women were the first computer programmers

[Brian Walenz via cctalk]

On Wed, Aug 23, 2017 at 8:59 PM, Al Kossow via cctalk  wrote:

>
> "Nathan Ensmenger has observed"
>
> he's written a whole book on the subject "The Computer Boys Take Over"
> https://mitpress.mit.edu/books/computer-boys-take-over
>
>
And:

"Recording Gender", Janet Abbate (also mentioned in the article)
https://mitpress.mit.edu/books/recoding-gender

"Programmed Inequality", Marie Hicks
https://mitpress.mit.edu/books/programmed-inequality

b

Re: Soldapullt original vs III

[Brian Walenz]

On Mon, Jan 16, 2017 at 12:35 PM, Jon Elson  wrote:

> [...]

a pump makes it work 10X better.  The trick, as described in the Pace
> manuals, is you heat the connection for several seconds, then apply vacuum
> and orbit the tip so it moves the component pin in the plated through
> hole.  That orbiting gets ALL the solder out of the hole.
>

While I wholeheartedly agree with the tool advice and the trick, I lifted a
bunch of traces on a PDP8a CPU board doing this.  I don't know if it was
the particular board or generally crappy manufacturing at issue here.  All
the HP test equipment I've fixed, most if not all from 1985+-7, survived
worse punishment.

I've also started reflowing and adding fresh solder before attempting to
desolder.  Could be better heat transfer, or just easier to suck up a
larger blob.

b

Re: Unknown keyboard

[Brian Walenz]

I've got one in the metal case.  On the back is a property tag:

Teledyne Ryan Aeronautical
E.T. "028400a"  [<- the 'a' in pen]
Gov't I.D. "MDA9729530013"
Prop. of "USAF"
R-5051-2-REV.5-93

Where the stuff in quotes is from a typewriter, the rest is form
boilerplate.  There are also some inventory control stickers from 1999 and
2001.

I made a new EPROM that made it output a unique code for each key, but I'd
have to dig up the notes to say anything useful.  I never figured out what
the daughter board was for and just removed it.

b

PDP8a CPU fixed! (was Re: DEC DELQA - seems not to work. Anyone got a spare?)

[Brian Walenz]

On Mon, Nov 7, 2016 at 11:44 AM, Ian S. King  wrote:

> I love reading stories of component-level repair.
>

Assuming my notes and sketchy memory make any sense:

One of my PDP 8a CPU boards (the M8315) passed all the self tests I could
toggle in, EXCEPT, it would ignore HLT instructions.  It'd just blow right
through them.  That'll get you questioning your sanity real quick.

Several hours of squinting at schematics said I'm looking for the STOPL
signal - I found three or four places, one of which involved a ROM (at
least my notes say there is a ROM involved).  Uh oh.  Page 3-17 of the
microprocessor user manual lists when STOPL is asserted.  Basically, front
panel or HLT.  Page 4-39 has the logic for the front panel, and that was
enough to narrow it down to one instance of STOPL in the schematics, in the
middle of page H-9.  E39 (an 8881 aka 7439) or E33 (a 7402).  I swapped
those two out, repaired the trace that I busted, and viola!  HLT now
works.  I vaguely remember it was the 8881 at fault.

BTW, I'm open to suggestions as to how to even begin debugging an HP 1000 E
Series.  There seems to be a case holding a power supply in the way of any
access to the motherboard.  The machine fails to exit the 'counting' self
test right after power up.  I plan on writing up a better description once
it gets cold and snowy out, so don't feel bad if you don't see this plea
for help.

Cheers!

b

Re: PDP-8 _Introduction_to_Programming_ & _Programming_Languages_(Scanned) Covers Needed

[Brian Walenz]

On Tue, Aug 2, 2016 at 8:20 PM, Bob Vines  wrote:

> Does anyone have DEC's PDP-8 _Introduction_to_Programming_, Editions 3
> and/or 4 and/or the PDP-8 _Programming_Languages_ handbooks?
>
> If you're not willing to part with your copy, could you scan the front
> covers of these handbooks and tell me which Edition(s) they are from?  I'm
> especially looking for the front cover that had the "format generator
> program" printed on it in the background.
>

I've got the 2nd and 3rd editions.  The 2nd has 'skip to service routines'
on the
cover, and the 3rd has 'two's complement single precision multiply routine'
on it.
They're pretty beat up though, lots of faded spots and a few creases.

I'm also looking for DEC's PDP-8 _Programming_Languages_.  If you are not
> willing to part with them, could you scan the front cover and tell me which
> Edition(s) it/they are from?
>

I have the first edition, and it is in very good shape.

I'll scan these a little later and send to you.

b

Re: Signetics N8251 source?

[Brian Walenz]

On Sun, Jul 24, 2016 at 5:01 AM, Mattis Lind  wrote:

> After successfully repairing the G231 module of the MM11-L set I continued
> with the next one. This one was not able to access addresses ending 0100
> (binary). Luckily it was not the transistors arrays that were bad but the
> selector chip. A Signetics N8251 chip.
>

I suspect that since you've debugged it already, this won't help.  Just in
case,
the datasheet is on page 52 of:

https://archive.org/details/bitsavers_signeticsdcs8000SeriesTTLMSI_11847693

/Mattis
>

b

multiflow trace in Austin

[Brian Walenz]

It's not as old as some would like, but it's definitely unique enough.

http://www.ebay.com/itm/UBER-RARE-MULTIFLOW-TRACE-14-300-COMPILER-VINTAGE-COMPUTER-processor-compiler-/112050410557?hash=item1a16b9943d:g:r2EAAOSw3YNXbtaY

b

Re: CDC 6600 - Why so awesome?

[Brian Walenz]

On Wed, Jun 22, 2016 at 12:01 PM, Noel Chiappa 
wrote:

   Werner Buchholz (editor), "Planning a Computer System: Project Stretch",
> McGraw-Hill, New York, 1962
>

http://ed-thelen.org/comp-hist/IBM-7030-Planning-McJones.pdf


> Speaking of books, there's also a CDC 6600 book:
>
>   Jim E. Thornton, "Design of A Computer: The Control Data 6600",
> Scott, Foresman, Glenview, 1970
>

http://www.textfiles.com/bitsavers/pdf/cdc/6x00/books/DesignOfAComputer_CDC6600.pdf

(apologies for using the non-official link)

Really gotta do that Bibliography!
>
> Noel
>

Ah, that's why my googling around the other day failed!  The current pace
of recommended books is already quicker than I can read.  Where is this
'computer history wiki', anyway?

b

Re: HP Series-80 computers - PRM-85 board case? ... maybe!

[Brian Walenz]

I have a printer - just finished putting a Rostock V2 together a week or so
ago - and an 87xm (and 86b, fwiw) and some modules, but no PRM-85.  If fit
against a standard module board is sufficient, I can do an iteration or
two.  I haven't quite finished calibration, but it is printing sufficiently
well so far.

Is the PRM-85 still available?

b


On Mon, Jun 20, 2016 at 5:54 PM, Dave  wrote:

> I'm interested as well.
> Dave
>
>
> On Monday, June 20, 2016 2:16 PM, "alexmcwhir...@triadic.us" <
> alexmcwhir...@triadic.us> wrote:
>
>
>
>  On 2016-06-20 11:34, Pete Plank wrote:
> >> On Jun 20, 2016, at 6:20 AM, martin.heppe...@dlr.de wrote:
> >>
> >> I read in this list that there are more people interested in such a
> >> case.
> >
> > I don’t have a 3D printer either, but I’m on board for one when
> > they’re ready to go - my PRM-85 is still in its anti-static bag.
> >
> > Pete
>
> I have a 3d printer, but not any of the boards in question. I don't mind
> helping if there's anything i can do.
>
>
>
>
>

Eckert - Faster, Faster; books in general

[Brian Walenz]

Is there an electronic copy of this floating around?  My (ex-library) copy
is missing all of chapter 11, "What is there to calculate?.  (And the last
page of the previous chapter).  The pages weren't ripped out, they were
missing when it was bound.  Very annoying, I enjoyed the book right up
until it crashed, so to speak.

Two, also ex-library, copies are listed on Amazon, and I hesitate to get
another copy with the same problem.  There are others, of course, at
outrageous prices.  Or maybe I don't realize the significance of '1st
edition, not ex-library'.

Just to make any discussion a bit more interesting, what would you suggest
along similar lines?  The two giant books on IBM (detailing "pre-360", and
"360") were quite fun too.

bri

Re: UNIBUS/QBUS interface chips Was: Re: MEM11 update

[Brian Walenz]

I did a bit of searching in the fall for an 8881 (to fix a busted HALT
instruction on a PDP8a).  I concluded the 7439 is a pin-for-pin replacement
- I can't claim all credit for this, it's probably known by a few people
here.  My notes say the 8881 will handle 30mA loads.  The 7401 will handle
16mA, while the 7439 will handle 80mA.

Cheers!

b


On Mon, May 2, 2016 at 10:04 AM, Mattis Lind  wrote:

> > The following chips have been used by DEC to interface to the QBUS, and
> > I have seen many of the above chips (e.g. 8641's) used there too, so I
> > think chips seen on one bus could be used on the other:
> >
> > Drivers:
> >
> > 7439 - Various - Quad NAND
> >
> > Transceivers:
> >
> > 2908 - AMD - Quad latching transceiver with tri-state output
> >
> > I _believe_ the following chips are also usable as UNIBUS/QBUS interface
> > chips, but I'm not sure if I've seen one used there:
> >
> > Transceivers:
> >
> > 8836 - National Semi - Quad NOR
> > 8838 - National Semi - Quad transceiver (aka Signetics N8T38)
> >
> > Quite a zoo!
> >
>
> DEC also used the DEC DC005 for the data and address lines on QBUS cards.
> The Signetics code is C2324N
>
> /Mattis
>
>
> >
> > Noel
> >
>

Re: Imaging RX02 disks for simh (was: Re: MU-BASIC V2 and RT-11 V03B distribution disks.)

[Brian Walenz]

On Sun, Mar 6, 2016 at 5:06 PM, Don North  wrote:


> From the SIMH pdp11 RX driver (pdp11_rx.c) the disk size is computed as
> follows,
> and the byte offset into the file is computed by CALC_DA(trk,sec) given
> the PHYSICAL
> track (0..76) and sector (1..26) addresses used in accessing the
> controller.
>
> So the SIMH disk image should be 77*26*128 = 256,256 bytes for an RX01
> format.
> RX02 format is same number of tracks and sectors, but has 256 byte sectors.
>
> So if you image an RX disk using logical operating system 512B blocks
> there are
> 494 of them (76*26*128/512 = 494) numbered 0..493. Track 0 is skipped in
> the
> filesystem (block 0 is at track=1 sector=1) for legacy compatibility
> reasons (with IBM).
>
> However, since the SIMH file is in physical track/sector order, if you
> read the disk image
> using logical device blocks, you have to know how the driver interleaves
> logical blocks
> onto physical track/sectors, as you must de-interleave to build the SIMH
> file.
>
> Or else you must run a program on the PDP-11 side that reads the RX drive
> as physical
> tracks and sectors, not using file system access commands.
>
> It's not pretty, but if you think about it enough it is the only way for
> SIMH to simulate the
> RX/RY devices and be operating system agnostic.
>
> Don
>
> From PDP11/pdp11_rx.c:
>
> #define RX_NUMTR77  /* tracks/disk */
> #define RX_NUMSC26  /* sectors/track */
> #define RX_NUMBY128 /* bytes/sector */
> #define RX_SIZE (RX_NUMTR * RX_NUMSC * RX_NUMBY) /* bytes/disk */
>
> #define CALC_DA(t,s) (((t) * RX_NUMSC) + ((s) - 1)) * RX_NUMBY
>


http://www.dbit.com/putr/putr.asm has the following:

;
; RX01 interleave routine.
;
; bplogical device rec
; chcylinder (0-75.)
; cllogical sector (0-25.)
;
; On return:
; chcylinder (1-76.)
; clsector (1-26.)
;
; From RT-11 V04 DY.MAC:
;
; ISEC=(ISEC-1)*2
; IF(ISEC.GE.26) ISEC=ISEC-25
; ISEC=MOD(ISEC+ITRK*6,26)+1
; ITRK=ITRK+1
;

(and then some assembly code to implement that)

I didn't try anything based on this.  I was confused about "ISEC-1".
Assuming sectors started at zero, this gave a negative result.  Plus, I was
wrong about the sector size.

Thanks!  This seems like enough hints to figure it out.

b

Re: Imaging RX02 disks for simh (was: Re: MU-BASIC V2 and RT-11 V03B distribution disks.)

[Brian Walenz]

On Sun, Mar 6, 2016 at 3:33 PM, Mattis Lind  wrote:

>
> Did you have problems with my RAW files as well? Which? I tested a few of
> them right now and they seemed to work fine.
>

Nope, no problems.  That was what triggered this...that someone else could
do it.

I jury rigged an RX50, and managed to get an image across that way.  My end
goal is to dump an RD52, but, sadly, I still am unable to access the disk.
Not even a blip on the activity light.  *Sigh*  Back to reading manuals, I
guess.

Thanks to everyone for confirming I'm not insane, a moron, or both.

b

Imaging RX02 disks for simh (was: Re: MU-BASIC V2 and RT-11 V03B distribution disks.)

[Brian Walenz]

How the heck do you copy an RX02 disk for use in simh?

I've been trying to transfer RX02 images between simh and a real PDP11
(that has only two RX02's, console, and ethernet).  So far, I've only
attempted sending an RX02 image from the PDP to simh, but simh fails to
read it: "?DIR-F-Invalid directory".  Even after adding 13*512 bytes to the
start for the missing track, I still get invalid directory.

My process is to COPY/DEVICE/FILES DY1:/START:0/END:330 DY0:BLOCK1.DAT,
then FTP that off the PDP, delete the file, and do the remaining two thirds
of the disk.  Once all are transferred, "cat *DAT > floppy.dsk".

I can transfer RX50 images using the same recipe, though I haven't tried
sending an RX50 image created on simh back to the PDP.

For what it's worth, I'm having the same problem with Alan Baldwin's TCP/IP
disk images from http://shop-pdp.net/rthtml/tcpip.htm.  simh can't read the
individual DSK images, but could read the *.PKG with the disks inside, and
from that, I could (RT-11) MOUNT each disk to a logical device.

b


On Thu, Jan 28, 2016 at 11:50 AM, Mattis Lind  wrote:

> I found some 8 inch floppies with distribution kits for MU-BASIC V2 and
> RT-11 V03B. I imaged those and put them here
> http://www.datormuseum.se/documentation-software/rx01-and-rx02-floppy-disks
> if anyone is interested in playing with MU-BASIC. There are both RAW disk
> images and to be used in SimH and like and also DMK/IMD files.
>
> The system that floppies came with is this little (
> http://www.datormuseum.se/computers/digital-equipment-corporation/pdp1103-l
> )
> system once used at Scania in Södertälje.
>

PDP 8a transformer capacitor replacement?

[Brian Walenz]

Having read all sorts of bad things about these older oil filled
capacitors, I decided to replace the one on my 8a.  I got what I think is a
replacement - 6 microF, 660VAC, 50/60Hz, "NO PCB's" - but it is physically
about 1/3 the size as the original.

Did the tech for these get that much better?

What purpose does this serve?  It's hanging off the transformer.  I see
lots of links about motor start capacitors, but nothing relating to
transformers.

http://www.mouser.com/ProductDetail/Cornell-Dubilier/SFA66S6K288B-F

Thanks,
b

Re: Cloud-cuckoo land

[Brian Walenz]

Don't forget about this one:

http://www.ebay.com/itm/191698368565

$17k for a CRT and a keyboard in a (beat up) wood case.  He's missing the
box with the electronics, and, clearly, the cables...  At least it isn't
signed!

b


On Sat, Sep 26, 2015 at 9:49 AM,  wrote:

> Pocket change compared to what the seller wants for this Olivetti
> Programma 101, priced to go!
>
> http://www.ebay.com/itm/Olivetti-PROGRAMMA-101-signed-by-one-of-the-authors-PRE-ALTAIR-8800-AND-C4004-/271973010365
> To me the signing on the top of the case sort of spoils the clean
> appearance, I think if would have been better if it had been on the bottom
> or inside the case. Not every
> designer is as famous as Woz :)
>
> Steve.
>
>

Re: LA120 ROM & new member intro

[Brian Walenz]

On Tue, Sep 22, 2015 at 9:29 PM, Paul Anderson  wrote:

What is the part number of the dead power supply you gave up on?
>

It's the H7864 (Astec aa12130) in the BA23 enclosure.

It powered up a few times, but now only the switch light comes on.  If I
remember, it wouldn't power up with just the cpu board (or maybe just the
cpu + memory), but with cpu, memory, disk controller + disks, it would
power up.  I was able to poke around in the 'boot menu' (enough to see that
the machine and serial port worked), and the next morning it wouldn't power
up.

I checked for cold solder joints, and replaced one of the three line filter
caps - the other two aren't the exploding type.  I'm getting power out of
the filter anyway and the rectifier is OK (voltage across the two caps).  I
don't know switching power supplies well enough to go poking around in
there.

What other DEC items do you have?
>

The MicroPDP (KDF11-BJ, 128 kw memory)

VAXstation 3100 (m48 sounds right) running OpenVMS (probably well expired
by now)

DECstation 5000/120 (+ 2x disk expansion) running Ultrix.  As I recall,
this was a DNS server at BBN.  I thought I saved the original bits, but I
see I was in the mucking about before I made the copy.

DECsystem 5000/200 - which I've been able to do nothing with.  I should
haul it out and see if I've gotten any smarter since the last time I tried
it.

LA120 DECwriter III (cleaned and repainted, NOS ribbon and a box of paper)
LA120 DECwriter III (dead; print head is jammed, and the 'LSI printer' IC
is bad)

PDP 8a/400 - 3x m8315 (one that ignores HALT, one that doesn't work, one
that hopefully works 100%), 2x m8316 & m8317 & 8k core)

PDP 11/34a + 2x RL01's - a winter project.  All I've done is clean out the
dust and whatnot.  I'm pretty sure I'm missing the cable to connect the
controller to the disks.  Annoyingly, one of the keypad buttons is busted
off, and previous 'repairs' (not mine!) screwed up the joint enough that I
had to make a bridge to glue it back together.  The membrane button below
it now feels weird - no 'click'.  I _really_ don't want to take this
apart.  Did that on the 8a, and it was a nightmare.

Where are you located?
>

Just north of Washington DC.  Anyone else?

b

LA120 ROM & new member intro

[Brian Walenz]

Hi. The original ROM request showed up just before I started receiving
messages this morning, and I only got the tail end of the chatter.  Instead
of tacking a reply on to that, I thought I'd just start a new thread and
introduce myself at the same time.

Here's what I think is 23-038e4-00 from an LA120 (with a bad print head,
and dead pin drivers as well).  I couldn't find anything to compare it
against, and the adapter is new.  So it might be gibberish.  I did see, at
least, [A-Z] in the dump, so maybe it's good.

As for the introduction, I started life on the Apple II in fourth grade or
thereabouts, finally got a Commodore 128, then an Amiga, then jumped over
to UNIX (BSD mostly) and stuck there for years doing software.  After
funding stopped being an issue, I decided to get back to more interesting
and/or simple hardware, and electronics in general.  I seem to have
collected a rather complete HP86/87, under the illusion of using it for an
GPIB controller.  I'm now wrestling with an apparently dead PSU on a
MicroPDP (actually, I just now gave up on it), and am slowly fixing up a
PDP-8/a.  It has two CPU boards, one of which ignores the HALT
instruction.  From the schematics, I think it's one faulty 74ls chip, but I
haven't tried fixing it -- the machine has been down for cleaning/painting
for many months.  I just got it put back together this weekend.  I also
swapped out the fans for modern (quiet) 12v fans (driven off an isolated
power supply powered by the original 120 vac fan supply)...and now hear the
transformer buzzing away.  Win some, lose some.  Sigh.  Congrats on making
it to the end!

Cheers!

b