RE: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Robert Jarratt]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jay West
> Sent: 03 March 2016 13:52
> To: 'General Discussion: On-Topic and Off-Topic Posts'
> <cctalk@classiccmp.org>
> Subject: RE: Recovery adventure - Re: Unidentified DEC gear available, NSW-
> AU
> 
> Pete wrote...
> -
> If you (or anyone here) has never worked on a teleprinter (Teletype or other
> make) please please please ask someone experienced. If not one can and
> many time has happened is all plastic parts of which there are many in a
> 32/33 and few in a 28/35/37 can be destroyed.
> 
> Having said that, if you end up with a 35, join the mailing list called
> "greenkeys".
> -
> 
> I have a very good condition ASR35, but it hasn't been on for 20 years at the
> least, probably much more than that. I know zero about it (or any tty for that
> matter). You can bet once I get to that point I'll be asking the tty wizards 
> here
> for help :)
> 
> Same goes for a couple ASR33's I have that are actually in marginal condition.
> 
> For whatever reason, I really want my tty's to run at some point, but they are
> not super high on the list given limited time. I will get to them some day
> though!
> 
> J


I can only add my voice to the plea to save the Model 35. Also, as someone else 
pointed out, Greenkeys is the place to go for advice on restoring Teletypes, 
the list if very friendly and exceedingly helpful.

Thanks for the interesting account and pictures. I hope it cleans up well!

Regards

Rob

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Todd Goodman]

Wow!  Excellent write up and photos!

Thank you!

* ste...@malikoff.com  [160302 17:51]:
> Well, it started with 'Unidentified DEC gear available, NSW-AU'...
> A few weeks ago you saw some poor quality photos Jay posted from someone who 
> had found a PDP-11 of some sort.
> It seems no-one could identify it or the ancillary equipment at the time. As 
> it happened to be located here
> in Oz, and only in the next state, I thought it was worth a gamble on going 
> to rescue it even though it was
> hundreds of kays/miles away and would mean a few days driving.
> 
> So I took last Thursday and Friday off work to drive down in my ute from 
> Brisbane to the gear's location. I drove
> the inland highway and just camped along the way each evening. The weather 
> was very warm and pleasant. During the
> evenings the mozzies were out in force, biting.
> 
> Arriving at the location first thing Saturday morning (as I had camped the 
> second night nearby) I was shown the
> horse stables where the gear was stored. It was near an entrance and the top 
> of the rack was covered with a tarp.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_01.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_02.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_03.jpg
> 
> The rack was sitting directly on the dirt floor. The stables hadn't been used 
> for decades as such and there was a
> lot of mouse and other animal droppings on everything. The front of the rack 
> was against some horse tying-up posts
> so we got to work levering it away from them to get to the front, for which I 
> had brought gloves.
> 
> http://www.surfacezero.com/g503/data/4173/gear_recovery_04.jpg
> 
> At this point I realised what I was looking at. It was a Foxboro Fox 2 
> computer, essentially a rebadged PDP-11/20.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_05.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_06.jpg
> 
> A while ago I had by chance downloaded and looked at the very same brochure 
> for this machine, I think perhaps
> because it had been mentioned here. So I was able to identify it immediately. 
> This is that brochure:
> http://archive.computerhistory.org/resources/text/Foxboro/Foxboro.Fox2-30.1972.102646170.pdf
> 
> The cabinet was about two and a half 19" rack-widths wide, painted lime green 
> and with custom industrial control
> equipment to the left and the computer, paper tape reader and expansion box 
> in the right. The half width section
> contained a series of power supplies. almost all cables had Winchester MRAC 
> connectors on them (visible in the
> original photos, and I happened to have a need for some for my Diablos).
> 
> There were no peripherals of any sort apart from the paper tape reader and 
> the custom A-D I/O. No disc drives nor
> the fabulous drum shown in the brochure.
> 
> At the bottom of the computer rack section there was a very sad PDP-11/05, 
> missing its console, and full of mud.
> Being at the bottom it had been flooded over the years and was silted up. It 
> had a cable to the BA-11 expansion
> cabinet.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_07.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_08.jpg
> 
> I started by removing the 11/05, as there was a (very very) slim chance I 
> might be able to use it for some spares,
> and I had a need for the BC-5 Power Control Unit in the chassis anyway. This 
> machine was not on rack slides but
> just lying on the bottom on the dirt. Surprisingly the paper label on the top 
> panel was still partly legible,
> considering the immersion.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_12.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_13.jpg
> 
> Next I worked on removing the BA-11. It was pretty much empty with only a 
> small Unibus backplane.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_14.jpg
> After that I attended to the Fox 2, and before long after a lot of sweating 
> we had the machine out and ready to
> load onto my ute.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_09.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_10.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_11.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_15.jpg
> 
> Finally I removed the Foxboro paper tape reader. The tape holders each side 
> slide up to reveal the rack mounting
> screws. Onto the ute it went.
> 
> There were some other racks of gear, but all custom idustrial control  
> equipment. One rack had a DEC A-D Converter
> in it with some serious cables connected to some backplanes of the smaller 
> Flip Chip modules. I grabbed the A-D
> and Flip Chips.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_16.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_17.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_18.jpg
> 

RE: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Jay West]

Pete wrote...
-
If you (or anyone here) has never worked on a teleprinter (Teletype or other 
make) please please please ask someone experienced. If not one can and many 
time has happened is all plastic parts of which there are many in a 32/33 and 
few in a 28/35/37 can be destroyed.

Having said that, if you end up with a 35, join the mailing list called 
"greenkeys". 
-

I have a very good condition ASR35, but it hasn't been on for 20 years at the 
least, probably much more than that. I know zero about it (or any tty for that 
matter). You can bet once I get to that point I'll be asking the tty wizards 
here for help :)

Same goes for a couple ASR33's I have that are actually in marginal condition.

For whatever reason, I really want my tty's to run at some point, but they are 
not super high on the list given limited time. I will get to them some day 
though!

J

RE: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Jay West]

Steven; 

So glad it was a productive trip. While some of that gear was obviously pretty 
severely damaged... the Fox 2 would have been worth the trip for me anyways :)

A return trip should be scheduled by you or the folks you were in 
contact/working with, for the boxes of documentation and for that 35 tty!

I do have that exact same paper tape reader, but mine is on a data general 
S120. On that system, whoever implemented it left off the two tape bins. I got 
the bins with the system, but there was no mounting spot for them. I guess they 
figured letting the tape cascade onto the floor was good enough :) Haven't 
figured out how they fed it though.

Best,

J

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Mattis Lind]

2016-03-03 9:36 GMT+01:00 Mattis Lind :

>
>
>
>>
>> Finally I removed the Foxboro paper tape reader. The tape holders each
>> side slide up to reveal the rack mounting
>> screws. Onto the ute it went.
>>
>> There were some other racks of gear, but all custom idustrial control
>> equipment. One rack had a DEC A-D Converter
>> in it with some serious cables connected to some backplanes of the
>> smaller Flip Chip modules. I grabbed the A-D
>> and Flip Chips.
>> http://www.surfacezero.com/g503/data/4173/gear_recovery_16.jpg
>> http://www.surfacezero.com/g503/data/4173/gear_recovery_17.jpg
>> http://www.surfacezero.com/g503/data/4173/gear_recovery_18.jpg
>> http://www.surfacezero.com/g503/data/4173/gear_recovery_19.jpg
>> http://www.surfacezero.com/g503/data/4173/gear_recovery_20.jpg
>>
>>
>>
>
> What is in picture 18? There is something very familiar with it. To me it
> looks like the backplane of a PDP-9. The core memory stack in the top.
>
> Compare with the RICM PDP-9:
>
>
> http://www.ricomputermuseum.org/Home/equipment/dec-pdp-9/PDP-9_Processor_Front.jpg
>
> I would be very interesting to see more pictures of the cabinet in picture
> 18.
>
> I also would guess that the the cabinet with the A/D converter (AF01A) in
> the top also hold a D/A converter (AA01A). It looks very much similar to
> the one we have with our PDP-9.
>
> https://dl.dropboxusercontent.com/u/96935524/Datormusuem/Exhibhall-8l-8e-rk07.png
> (the cabinet next to the RK07)
>
> /Mattis
>
>

Just checked the list of 18 bits installations that Bob Supnik made
available:
https://dl.dropboxusercontent.com/u/96935524/Datormusuem/18bitServiceList1972.pdf

There is a PDP-9, s/n 209 delivered to Australia Iron & Steel.

It had a AF01B (A/D converter) s/n 195 and a AA05B (I am not sure how it
differs from AA01) s/n 101. It is also supposed have an extra memory
cabinet since it had two memory stacks.
There are also two items which I would guess is non standard options: "76
05404" and "76 05426".

Check the AF01 you got is matching the serial number.

It was delivered in 1969.

There are a few flexiprint cables dangling in the foreground. I think those
are the ones that are supposed to connect with the front panel. So someone
has probably taken the frontpanel. Maybe that is way it is not recognised
as a PDP-9.

/Mattis

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Pontus Pihlgren]

On Thu, Mar 03, 2016 at 09:36:07AM +0100, Mattis Lind wrote:
> >
> > Finally I removed the Foxboro paper tape reader. The tape holders each
> > side slide up to reveal the rack mounting
> > screws. Onto the ute it went.
> >
> > There were some other racks of gear, but all custom idustrial control
> > equipment. One rack had a DEC A-D Converter
> > in it with some serious cables connected to some backplanes of the smaller
> > Flip Chip modules. I grabbed the A-D
> > and Flip Chips.
> > http://www.surfacezero.com/g503/data/4173/gear_recovery_16.jpg
> > http://www.surfacezero.com/g503/data/4173/gear_recovery_17.jpg
> > http://www.surfacezero.com/g503/data/4173/gear_recovery_18.jpg
> > http://www.surfacezero.com/g503/data/4173/gear_recovery_19.jpg
> > http://www.surfacezero.com/g503/data/4173/gear_recovery_20.jpg
> >
> >
> >
> 
> What is in picture 18? There is something very familiar with it. To me it
> looks like the backplane of a PDP-9. The core memory stack in the top.

It has to be, the layout of the flipchips and colors all match!

The white strips are probably foam, I've seen the same in a LINC-8.

/P

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Mattis Lind]

>
> Finally I removed the Foxboro paper tape reader. The tape holders each
> side slide up to reveal the rack mounting
> screws. Onto the ute it went.
>
> There were some other racks of gear, but all custom idustrial control
> equipment. One rack had a DEC A-D Converter
> in it with some serious cables connected to some backplanes of the smaller
> Flip Chip modules. I grabbed the A-D
> and Flip Chips.
> http://www.surfacezero.com/g503/data/4173/gear_recovery_16.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_17.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_18.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_19.jpg
> http://www.surfacezero.com/g503/data/4173/gear_recovery_20.jpg
>
>
>

What is in picture 18? There is something very familiar with it. To me it
looks like the backplane of a PDP-9. The core memory stack in the top.

Compare with the RICM PDP-9:

http://www.ricomputermuseum.org/Home/equipment/dec-pdp-9/PDP-9_Processor_Front.jpg

I would be very interesting to see more pictures of the cabinet in picture
18.

I also would guess that the the cabinet with the A/D converter (AF01A) in
the top also hold a D/A converter (AA01A). It looks very much similar to
the one we have with our PDP-9.
https://dl.dropboxusercontent.com/u/96935524/Datormusuem/Exhibhall-8l-8e-rk07.png
(the cabinet next to the RK07)

/Mattis

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Brent Hilpert]

On 2016-Mar-02, at 2:50 PM, ste...@malikoff.com wrote:
> At this point I realised what I was looking at. It was a Foxboro Fox 2 
> computer, essentially a rebadged PDP-11/20.


Remarkable find that - a Fox-2-badged 11 - amazing to come across.
Great rescue, although too bad the racks weren't included as that's part of the 
Foxboro packaging.

If you've seen the CHM brochure of the Fox-1 previously, just ran across a 
great pic of a Fox-1 system with a great view of the X-shaped CPU:
https://www.flickr.com/photos/64900616@N04/23796530491


On 2016-Mar-02, at 6:08 PM, Pete Lancashire wrote:
> Having said that, if you end up with a 35, join the mailing list called
> "greenkeys". Greenkeys is slang for teleprinter 'nuts' and the name
> comes from the color of the keycaps in later Teletype machines..

.. I suspect you meant earlier machines there - the 15,19,26 and so on of the 
1920-40s were the machines with the green keys.

I've worked on a 33 and a couple of 28s to get them going but can't claim to be 
an expert.
Have a 15, two 14s (tape-printers), a Lorenz (19 knockoff), military TT-4A, and 
a 26 that need restoration - someday when I have opportunity.

Indeed it would be sad to see the 35 scrapped. The oil does help protect them 
when stored in a poor environment so the mech may well be OK or restorable.

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Alexandre Souza]

Nice photos!


2016-03-02 23:08 GMT-03:00 Pete Lancashire :

> If you (or anyone here) has never worked on a teleprinter (Teletype or
> other make) please please please ask someone experienced. If not one can
> and many time has happened is all plastic parts of which there are many in
> a 32/33 and few in a 28/35/37 can be destroyed.
>
> Having said that, if you end up with a 35, join the mailing list called
> "greenkeys". Greenkeys is slang for teleprinter 'nuts' and the name
> comes from the color of the keycaps in later Teletype machines.. And some
> on the list can give good advice, some not so much. There are members who's
> job was to service these beasts. I have had machines brought to me that
> were basically destroyed and would have
> been easy fixes if left alone before hand.
>
> Please never turn one on unless they have been checked out.
>
> Sorry to butt-in but hate to see them get messed up.
>
> -pete
>
>
>
> On Wed, Mar 2, 2016 at 3:49 PM, Christian Gauger-Cosgrove <
> captainkirk...@gmail.com> wrote:
>
> > On 2 March 2016 at 17:50,   wrote:
> > > The I/O for the machine was (I believe) an ASR-35 the bigger brother to
> > the ASR-33. I couldn't take it, it was
> > > wedged in behind the other racks and I had only a limited amount of
> time
> > to load the equipment before I had to
> > > head back interstate to home. I did not see any sign of the optional
> I/O
> > Selectrics shown in the brochure, as I
> > > would definately have liked to have found those if I could have! I
> don't
> > think this machine had them, only the
> > > ASR-35, as no printout I found appeared to be done by a Selectric.
> > >
> > You definitely want that 35ASR. They're absolute tanks, and you could
> > probably bring it back up with a bit of oil and grease from its
> > current state (I exaggerate somewhat).
> >
> > The Model 35 series of Teletypes just isn't as common as the Model 33
> > machines (though I think the "rarest" 35 right now is either the 35KSR
> > or 35RO; with the 35ASR being more common). They are definitely
> > worthwhile to have, since their mechanism is more robust and sturdy
> > than the mechanism of the Model 33, since the Model 35 is based on the
> > older (5-bit) Model 28 mechanisms (extended to 8-bit).
> >
> >
> > Cheers,
> > Christian
> > --
> > Christian M. Gauger-Cosgrove
> > STCKON08DS0
> > Contact information available upon request.
> >
> >
>

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Pete Lancashire]

If you (or anyone here) has never worked on a teleprinter (Teletype or
other make) please please please ask someone experienced. If not one can
and many time has happened is all plastic parts of which there are many in
a 32/33 and few in a 28/35/37 can be destroyed.

Having said that, if you end up with a 35, join the mailing list called
"greenkeys". Greenkeys is slang for teleprinter 'nuts' and the name
comes from the color of the keycaps in later Teletype machines.. And some
on the list can give good advice, some not so much. There are members who's
job was to service these beasts. I have had machines brought to me that
were basically destroyed and would have
been easy fixes if left alone before hand.

Please never turn one on unless they have been checked out.

Sorry to butt-in but hate to see them get messed up.

-pete



On Wed, Mar 2, 2016 at 3:49 PM, Christian Gauger-Cosgrove <
captainkirk...@gmail.com> wrote:

> On 2 March 2016 at 17:50,   wrote:
> > The I/O for the machine was (I believe) an ASR-35 the bigger brother to
> the ASR-33. I couldn't take it, it was
> > wedged in behind the other racks and I had only a limited amount of time
> to load the equipment before I had to
> > head back interstate to home. I did not see any sign of the optional I/O
> Selectrics shown in the brochure, as I
> > would definately have liked to have found those if I could have! I don't
> think this machine had them, only the
> > ASR-35, as no printout I found appeared to be done by a Selectric.
> >
> You definitely want that 35ASR. They're absolute tanks, and you could
> probably bring it back up with a bit of oil and grease from its
> current state (I exaggerate somewhat).
>
> The Model 35 series of Teletypes just isn't as common as the Model 33
> machines (though I think the "rarest" 35 right now is either the 35KSR
> or 35RO; with the 35ASR being more common). They are definitely
> worthwhile to have, since their mechanism is more robust and sturdy
> than the mechanism of the Model 33, since the Model 35 is based on the
> older (5-bit) Model 28 mechanisms (extended to 8-bit).
>
>
> Cheers,
> Christian
> --
> Christian M. Gauger-Cosgrove
> STCKON08DS0
> Contact information available upon request.
>
>

Re: Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[Christian Gauger-Cosgrove]

On 2 March 2016 at 17:50,   wrote:
> The I/O for the machine was (I believe) an ASR-35 the bigger brother to the 
> ASR-33. I couldn't take it, it was
> wedged in behind the other racks and I had only a limited amount of time to 
> load the equipment before I had to
> head back interstate to home. I did not see any sign of the optional I/O 
> Selectrics shown in the brochure, as I
> would definately have liked to have found those if I could have! I don't 
> think this machine had them, only the
> ASR-35, as no printout I found appeared to be done by a Selectric.
>
You definitely want that 35ASR. They're absolute tanks, and you could
probably bring it back up with a bit of oil and grease from its
current state (I exaggerate somewhat).

The Model 35 series of Teletypes just isn't as common as the Model 33
machines (though I think the "rarest" 35 right now is either the 35KSR
or 35RO; with the 35ASR being more common). They are definitely
worthwhile to have, since their mechanism is more robust and sturdy
than the mechanism of the Model 33, since the Model 35 is based on the
older (5-bit) Model 28 mechanisms (extended to 8-bit).


Cheers,
Christian
-- 
Christian M. Gauger-Cosgrove
STCKON08DS0
Contact information available upon request.

Recovery adventure - Re: Unidentified DEC gear available, NSW-AU

[steven]

Well, it started with 'Unidentified DEC gear available, NSW-AU'...
A few weeks ago you saw some poor quality photos Jay posted from someone who 
had found a PDP-11 of some sort.
It seems no-one could identify it or the ancillary equipment at the time. As it 
happened to be located here
in Oz, and only in the next state, I thought it was worth a gamble on going to 
rescue it even though it was
hundreds of kays/miles away and would mean a few days driving.

So I took last Thursday and Friday off work to drive down in my ute from 
Brisbane to the gear's location. I drove
the inland highway and just camped along the way each evening. The weather was 
very warm and pleasant. During the
evenings the mozzies were out in force, biting.

Arriving at the location first thing Saturday morning (as I had camped the 
second night nearby) I was shown the
horse stables where the gear was stored. It was near an entrance and the top of 
the rack was covered with a tarp.
http://www.surfacezero.com/g503/data/4173/gear_recovery_01.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_02.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_03.jpg

The rack was sitting directly on the dirt floor. The stables hadn't been used 
for decades as such and there was a
lot of mouse and other animal droppings on everything. The front of the rack 
was against some horse tying-up posts
so we got to work levering it away from them to get to the front, for which I 
had brought gloves.

http://www.surfacezero.com/g503/data/4173/gear_recovery_04.jpg

At this point I realised what I was looking at. It was a Foxboro Fox 2 
computer, essentially a rebadged PDP-11/20.
http://www.surfacezero.com/g503/data/4173/gear_recovery_05.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_06.jpg

A while ago I had by chance downloaded and looked at the very same brochure for 
this machine, I think perhaps
because it had been mentioned here. So I was able to identify it immediately. 
This is that brochure:
http://archive.computerhistory.org/resources/text/Foxboro/Foxboro.Fox2-30.1972.102646170.pdf

The cabinet was about two and a half 19" rack-widths wide, painted lime green 
and with custom industrial control
equipment to the left and the computer, paper tape reader and expansion box in 
the right. The half width section
contained a series of power supplies. almost all cables had Winchester MRAC 
connectors on them (visible in the
original photos, and I happened to have a need for some for my Diablos).

There were no peripherals of any sort apart from the paper tape reader and the 
custom A-D I/O. No disc drives nor
the fabulous drum shown in the brochure.

At the bottom of the computer rack section there was a very sad PDP-11/05, 
missing its console, and full of mud.
Being at the bottom it had been flooded over the years and was silted up. It 
had a cable to the BA-11 expansion
cabinet.
http://www.surfacezero.com/g503/data/4173/gear_recovery_07.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_08.jpg

I started by removing the 11/05, as there was a (very very) slim chance I might 
be able to use it for some spares,
and I had a need for the BC-5 Power Control Unit in the chassis anyway. This 
machine was not on rack slides but
just lying on the bottom on the dirt. Surprisingly the paper label on the top 
panel was still partly legible,
considering the immersion.
http://www.surfacezero.com/g503/data/4173/gear_recovery_12.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_13.jpg

Next I worked on removing the BA-11. It was pretty much empty with only a small 
Unibus backplane.
http://www.surfacezero.com/g503/data/4173/gear_recovery_14.jpg
After that I attended to the Fox 2, and before long after a lot of sweating we 
had the machine out and ready to
load onto my ute.
http://www.surfacezero.com/g503/data/4173/gear_recovery_09.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_10.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_11.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_15.jpg

Finally I removed the Foxboro paper tape reader. The tape holders each side 
slide up to reveal the rack mounting
screws. Onto the ute it went.

There were some other racks of gear, but all custom idustrial control  
equipment. One rack had a DEC A-D Converter
in it with some serious cables connected to some backplanes of the smaller Flip 
Chip modules. I grabbed the A-D
and Flip Chips.
http://www.surfacezero.com/g503/data/4173/gear_recovery_16.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_17.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_18.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_19.jpg
http://www.surfacezero.com/g503/data/4173/gear_recovery_20.jpg

There is an identical DEC A-D on eBay at the moment which shows you what it's 
like:
http://www.ebay.com/itm/Digital-DEC-A-D-Converter-/141324598814

The I/O for the machine was (I believe) an ASR-35 the bigger