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A what is it thread? Hnad wired wrapped board.

targeteye

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Dec 19, 2016
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Houston, Texas
I have this board that I acquired mostly because I was just blown away by all the work that went into it. I showed to some folks on the IRC chat room last night and there were some theories. Without leading the witness here i'm interested in seeing if we can identify what it is.

It appears to be signed ERM 2-7-77.
 

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targeteye

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more pics
 

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zombienerd

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Looking at the back of the board, I'm pretty sure I've found my nightmare fuel for the next year. Thank you for your service in sharing this.

That is simultaneously amazing and horrifying.
 

krebizfan

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The two TI chips are data separators. The overall look suggests mini-computer prototype drive IO system. Which mini and what type of drive are aspects I'm drawing a blank on.

How many pins are in the socket at the front of the board?
 

targeteye

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Messages
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Location
Houston, Texas
The two TI chips are data separators. The overall look suggests mini-computer prototype drive IO system. Which mini and what type of drive are aspects I'm drawing a blank on.

How many pins are in the socket at the front of the board?

Hey Krebizfan,
The board is full of TI chips. Can you be more specific?

The connector on the top of the board is Dual row 50pin.
 

krebizfan

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The big TI chips labeled SN74S181J are officially Arithmetic Logic Units. (Oops, not sure what I looked up instead.) There a lot of SN74S240N chips which are listed as buffers and line drivers octal which fits with I/O card idea.

I can't read the other big chips information. They have MMI (?) logos on them. Guess work but I always used the rule of thumb that big chips are more likely to indicate card function. At least faster than trying to figure how groups of smaller chips are connected together.
 

Chuck(G)

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Looks pretty typical for a wirewrap board of the time (75-78). Given the connector on the board, I'm guessing that it's a disk controller. Some additional detail of the area near the connector would be nice. The large MMI DIPs are 512x8 bipolar PROMs, which would fit in this role.
 
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James0555

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May 5, 2008
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Merritt Island, Fl
Makes me think of the old Radiation Inc (Now Harris) PCM Decommutators we used for satellite data extraction back in the 70s used octal programming - it had several panels of 50 to 60 - 5400 series (Mil Spec 7400) TTLs ICs and all wire wrapped with white wire - Had to take a training class that lasted 6 weeks and was nothing but tracing logic circuits and making clock diagrams. Even then it was still a beast to troubleshoot when it didn't work.
 

targeteye

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Houston, Texas
Ok so humor me 'cause I don't really now that much of what I speak.

I think its a 16 Bit CPU and here is why,

1. 4 X 74181 ALU Seemed to be the besis for many 16 bit TTL CPU's.
2. 4 x 6341-1J 512 x 8 PROM with designators 1d,2d,3d,4d
3. 3 x 74s189

Other Ram chips as well.

Seems to have very similar chip sets to many other TTL CPUs of the time.

since it is a prototype the interface at the top couple be for lab work definately some sort of I/O. Very well could be disk controller as well.

Thoughts? I can find any example of a disck controller using ALU's.

Steve
 

Chuck(G)

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It could be--but then, "what's a CPU?". It could be a special one-off for data acquisition or control and not a general-purpose CPU at all. Or simply an unsuccessful prototype--back in the day, there was no point to tearing these things down--you just binned it and went on.

I've got a couple of similar VME boards populated with 10K series ECL, registers and all. The ram boards are full of the InMOS IMS1403 static RAMs, like the CPU board, in a x12 bit configuration. CPU? Maybe. Who would be nuts enough to do a 12-bit CPU in ECL, though?

FWIW, I tried to flog the SRAMs (96 of them) here a couple of times. No takers at $1 each, even though $gold$.
 

Uniballer

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Do not assume that this *must* be a prototype, or that it must have been hand wrapped. It may be, but I used to work for a company that had built a bunch of production stuff for the US Navy that was all wire wrapped using a computer-controlled wire wrapping machine (Gardner Denver?), and the same yellow wire. The Navy said they wanted it that way (apparently some study showed greater reliability for wire wrap than solder joints under certain conditions).
 
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KC9UDX

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Lutenblag
Under all conditions, if it's done right. And it should be if it's done by hnad, but is almost guaranteed to be if done by mcahine.
 

krebizfan

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The production wirewrap boards from DEC had silk screen markings on the front to help align all the inserted chips. One chip off by one hole is great way to have very long testing requirements and would cause difficulties with machine wire wrapping.
 

Chuck(G)

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I'm not debating the reliability of wire-wrap. The telcos have used it for decades. I still use it, believe it or not.

But the layout of the board strikes me more as either pre-production or prototype.
 

targeteye

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Joined
Dec 19, 2016
Messages
21
Location
Houston, Texas
It could be--but then, "what's a CPU?". It could be a special one-off for data acquisition or control and not a general-purpose CPU at all. Or simply an unsuccessful prototype--back in the day, there was no point to tearing these things down--you just binned it and went on.

I've got a couple of similar VME boards populated with 10K series ECL, registers and all. The ram boards are full of the InMOS IMS1403 static RAMs, like the CPU board, in a x12 bit configuration. CPU? Maybe. Who would be nuts enough to do a 12-bit CPU in ECL, though?

FWIW, I tried to flog the SRAMs (96 of them) here a couple of times. No takers at $1 each, even though $gold$.

Well certainly could be some sort of application specific controller. I just think its cool as beans. Perhaps I'm just too new to this to realize this is really just something ordinary or common.
 
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targeteye

Member
Joined
Dec 19, 2016
Messages
21
Location
Houston, Texas
Do not assume that this *must* be a prototype, or that it must have been hand wrapped. It may be, but I used to work for a company that had built a bunch of production stuff for the US Navy that was all wire wrapped using a computer-controlled wire wrapping machine (Gardner Denver?), and the same yellow wire. The Navy said they wanted it that way (apparently some study showed greater reliability for wire wrap than solder joints under certain conditions).

I think the loops and lengths are too random to be done via automation. Plus notice all the empty sockets rewired with power and bypass caps indicating the the board was first loaded out with an uncertainty as to its final configuration.
 
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