Author Topic: EEVblog #960 - Mystery Merry Mailbag Teardown  (Read 10791 times)

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Offline EEVblog

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EEVblog #960 - Mystery Merry Mailbag Teardown
« on: December 26, 2016, 04:46:21 pm »
« Last Edit: December 26, 2016, 06:07:38 pm by EEVblog »
 
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Offline Carl_Smith

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #1 on: December 26, 2016, 05:27:04 pm »
I have a box in the closet with a bunch of IBM circuit boards that looks similar to the ones in this device.  Same metal can covered chips and boards with a grids of square pads.   Guess I'll have to dig the box out and take a look, and maybe post some pictures.

Apparently this thing is a "Floppy Drive Maintenance Device."
https://www.frontiercomputercorp.com/ibm/tbt-a-vintage-ibm-901x-002-floppy-drive-maintenance-device/
 
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Offline EEVblog

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Offline EEVblog

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #3 on: December 26, 2016, 06:07:59 pm »
 
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Offline Koldman

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #4 on: December 26, 2016, 06:22:01 pm »
Too late to make xmas lights from them!
 

Offline trophosphere

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #5 on: December 26, 2016, 06:57:39 pm »
I believe the boards with the metal cans make up IBM's Palm (Put All Logic in Microcode) Processor.

This website has a whole bunch of information and pictures detailing the various boards as well as those metal cans (Bipolar gate arrays).
 

Online Halcyon

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #6 on: December 26, 2016, 07:48:47 pm »
Thanks for that Dave, very interesting. Perhaps you could turn that LED display into a bedside clock or have it scroll some stuff or something?
 

Offline Nogtail

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #7 on: December 26, 2016, 10:07:14 pm »
Is that a glimpse of the new meter we see near the end?
 

Offline SeanB

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #8 on: December 26, 2016, 10:22:49 pm »
IBM made those boards with multiple ground and power planes in them, thus giving a very low impedance power supply for the logic, plus the capacitance of those boards meant they could get away with only a few bulk capacitors per board. There are 3 pin decoupling capacitors though, and 4 pin as well, which have a ferrite bead on the incoming power side, a built in tantalum bead or ceramic chip capacitor and then a load side. The chip looks like those black resistor arrays, just 3 or 4 pins wide, and is moulded IC resin.

The reason for all the pads is so you can always connect to internal nodes, or do layer changes inside, and have full bed of nails test access to the board, with or without components on it. Thus a production change, or a version for a specific application would likely have a modification done, either drilling out a pad to isolate a trace, then use a jumper wire to move the trace, or like here to fix a fault detected after assembly. As the parts are all IBM parts ( down to the screws, the labels and even the lacing twine, which probably was still a part number from Apollo days) and all the tools are IBM part numbered, they had very little issue with reverse engineering, as non original parts would stand out glaringly. They even had entire hardware tool sets designed to fit IBM screws, bolts and nuts perfectly without marring the finish.

You thought flip chip is recent, those aluminium cans are a combination of flip chip, with a solder bump on the die to make contact, and beam lead transistors and diodes, along with SSI chips, resistors ( there are resistors in the smaller cans, especially those with lower part numbers, which may even date from the 1960's when they started making them), capacitors and multilayer ceramic traces, made so they could make a reliable sealed package. They were common, even though the stock might have ranged in complexity from 5 transistors in one to almost a full processor. All encapsulated internally with Parylene, that soft transparent coating, so they would still be reliable even if the hermetic case was compromised.
 
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Offline HighVoltage

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #9 on: December 26, 2016, 10:36:29 pm »
The "Briefcase" was made by Samsonite, specifically for test equipment and we used lots of them in the 80's
I had forgotten about those.

Great Christmas video.

 
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Offline ericloewe

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #10 on: December 26, 2016, 11:25:01 pm »
The Land Grid Array reference is almost certainly unrelated to this thing. That's the name Intel uses for their sockets (hence LGA115x or LGA2011).
 

Offline GoneTomorrow

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #11 on: December 27, 2016, 12:21:40 am »
The Land Grid Array reference is almost certainly unrelated to this thing. That's the name Intel uses for their sockets (hence LGA115x or LGA2011).

It's a general socket type, not specific to Intel. AMD uses LGA in their C32, G34, etc, sockets, mainly for servers.
 

Offline jonovid

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #12 on: December 27, 2016, 01:56:10 am »
the video at 18:45 matrix displays. :-+
good idea Dave, those matrix displays need reviving, So when you're done with the nixie project.
I would like to see a classic digital display racks or wall in the lab. as lab background, or video set backdrop. 
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Offline hamzadis

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #13 on: December 27, 2016, 02:02:04 am »
It seems these boards are related to an IBM tech called Solid Logic Technology (SLT). It's very old tech dating back to the 60s, but seems like an upgrade of the previous IBM tech called SMS. The idea is the same - making reusable blocks that could be plugged together easily, what would later become ICs. These blocks were mounted on ceramic plates which were then mounted on the grid PCBs. You can see some examples in the wiki article. They look a lot like the one Dave decapped, but simpler.

Now, all the resources I can find only talk about these ceramic blocks, it doesn't say anywhere why the PCBs were made as grids. I think it's possible the boards were manufactured like that to save on pad drilling time. Instead of drilling holes one by one which would require time and setup costs, they probably just punched them all at once in the regular pattern.

It's also interesting that 60s tech would be used in something seemingly manufactured in the 80s.

Here's some of the links I found talking about this: one, two, three. Also found this nice video showing the manufacture of these ceramic blocks:

« Last Edit: December 27, 2016, 02:16:03 am by hamzadis »
 
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Offline GreggD

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #14 on: December 27, 2016, 02:35:56 am »
I've got some of those smart led displays from TI. Used them in the 80's. Interesting that IBM made this unit in small numbers but still U.L.-ed it.
 

Offline SeanB

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #15 on: December 27, 2016, 02:54:47 am »
I've got some of those smart led displays from TI. Used them in the 80's. Interesting that IBM made this unit in small numbers but still U.L.-ed it.

Not really, these would have been used in large installations, and they would require all equipment that is used there, from the concrete in the footings, to the nails in the roof, to have a UL or other certification that it meets safety standards. Likely for IBM it was easy as well to simply send the first unit ( seeing as the one Dave has is number 2) for certification, and then use the number. Also likely is the number is for the standard IBM small power supply used in the unit, which would be the part most needing certification for mains connection, and providing protection against faults in the rest of the device causing damage.
 

Offline GeoffreyF

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #16 on: December 27, 2016, 02:58:01 am »
Hi,
I went to my first year of college at Vassar in Poughkeepsie. My family had a house about 20 minutes from there in Poughquag. I learned to sell well early on.   These are native american names.  Although IBM's corporate HQ was not far away in Armonk (dutch name), Poughkeepsie was where they built their mainframes at least in the IBM 360 days but probably after as well.  I visited the assembly line where ladies made core memories in fact.  There was a jig for the XY part but the sense line was literally put in by hand with a needle.   I had access to APL 360 on one of the first time sharing systems.  Look up that language - it was weird and strange, unlike any other.

It's pronounced Poke-Kip-see.   The city is on the Hudson river about 2 hours north of New York City.  Armonk is about half way.  Poughkeepsie is in Dutchess County and about 40 minutes south of Hyde Park, the home of President Franklin Roosevelt.   Woodstock, of rock concert fame was a similar distance, a very happy thing for college students but possibly too happy.

Geoff
 

Offline woox2k

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #17 on: December 27, 2016, 02:59:14 am »
Yes please do something with those displays! They look awesome.
 

Offline GreggD

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #18 on: December 27, 2016, 03:07:09 am »
Back around 1971 NCR, "National cash Register" made an infomercial showing how they made core memory. The memory card was on  a shaker table and the cores danced across the card until they fell into blind holed in the card.  No pick & place needed.
 

Offline richfiles

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #19 on: December 27, 2016, 04:03:20 am »


The HP9825 used those displays. The early 9825A had a "chicklet" keyboard, and red tinted encapsulation on the LED part. Since they already used a red window, they switched to a clear encapsulated LED display in later A models and the 9825B (not to mention a proper keyboard), to improve the overall brightness. They are pretty simple devices. Rows are selected by a 28 step serial in-parallel out shift register.  The 5 columns of each of the four characters are all tied to 5 external pins.

Pardon the message on my HP9825's LED display... I was trolling some conspiracy nutters online the day I took that picture!  :-DD
« Last Edit: December 28, 2016, 04:19:59 pm by richfiles »
 
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Offline BiOzZ

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #20 on: December 27, 2016, 04:42:09 am »
As i said on the video the only thing i can think of for the grid PCBs are that they had etchable PCB with a grid of holes on it manufactured in bulk, than etched them in house to prevent the need to drill tons of holes and threw plate them
you can use the holes as vias or to solder in chips than have some poor intern figure out where to place the chips perfectly then solder them

its not an LGA as both linear grid array and land grid array are socket types
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Offline GreggD

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #21 on: December 27, 2016, 04:51:47 am »
Wow richfiles, I used that calculator in 1976.
 
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Offline TheAmmoniacal

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #22 on: December 27, 2016, 06:51:46 am »
Is that a glimpse of the new meter we see near the end?

That is the super secret multimeter that has a 15V diode test range  ;D
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Offline alien_douglas

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #23 on: December 27, 2016, 10:28:19 am »
Hi Dave, Merry Christmas.

I used to work for IBM in the late seventies and early eighties  doing electronic repair on all types of IBM systems.
The unit that you have was indeed used for mainframe diagnostics back in the day. And yes, we had a number of these suitcases in New Zealand so there would have been a lot of them made.
I never worked on mainframes so I never used one of these but I did repair a couple.
Field Engineers would often shut the case, with the diskette still inserted, and bend it over. Not a great design!
The diskette had all the code (Microcode in IBM speak) to boot up the device and get it functional. From distant memory, the display should show an error if the diskette was not inserted on power on.
Thats about all I can remember about the unit but I do know a few things about the grid PCBs.

I don't know what IBM called the style of that grid arrangement but it was used in the majority of IBM equipment in the 70s and 80's. (Terminals, modems, mainframes, mid range systems, communication controllers, disk drives, tape drives, electronic typewriters, matrix and line printers. Pretty much everything.)

It is multilayer, four layer at least, with plated through pads at 0.1" everywhere. I think that IBM must have had a process to make them that could easily have the traces added where needed. So you could place chips and passive components anywhere on the board and use all the other holes as vias.
Most boards have spring contacts soldered along the edges and green plastic covers snapped over them. Some boards have these connectors on both ends of the board and once plugged into the main mother board, crossover connectors connected the rears of boards where necessary. The boards also typically had a plastic frame clipped around them that had guides and eject levers so engineers could easily insert and remove them from equipment. (Not so in space constrained test gear.)

Just some other information.
Bypass capacitors, when used, where typically single caps (Not arrays). They where pretty much the same size as the resistor arrays but only 2 pins long.
The big silver aluminium cans..  We called these 'Duchess Modules' (Their code name. Everything in IBM had a code name.) They were always through hole (I know as I have desoldered thousands of them.) They came in different pin configurations depending on the number of wires that the chip needed. There were literally hundreds of different types. The IBM PS/2 (1987) even used them.
The smaller cans had different configurations too. Sometimes they where as simple as just containing four transistors.

And finally for those who want a blast from the past..
IBM created circuit diagrams of their equipment using line flow printers (No graphic laser printers back in the 70s and 80s.) These massive printouts, called Automated Logic Diagrams (ALD) where a site to behold.


And I do remember a couple of the ALD pages for an IBM 3741 (Like a card punch machine but it wrote to 8" diskettes instead of punching cards) that were labeled C3PO and R2D2. IBM engineers had a sense of humour... :)

Alien
 
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Offline Don Hills

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Re: EEVblog #960 - Mystery Merry Mailbag Teardown
« Reply #24 on: December 27, 2016, 10:56:35 am »
Just a few additions to Alan's excellent summary:
I used the MD on several different system types. They were intended as a "Swiss army knife" tool. As well as mainframe peripherals (disk drives etc),  they were used on other non-mainframe products. The S-loop was a serial loop cabling system that interconnected IBM Retail Store System devices (3650, 4680), and the R-loop was for the 8100 Distributed Processing System. (See Wikipedia.)
It was really easy to bump the lid closed while working around the device. I usually used my largest screwdriver to prop the lid open. It saved me several times.

 


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