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Pre-production IBM 5170 motherboard on eBay

modem7

modem7

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Regarding eBay item 390024973091 - pre-production IBM 5170 motherboard at $850

* I'm very sure the "AMI" written on the ROMS is an abrieviation of American Megatrends Inc.

* In the 80s, when the company I worked for received boards (of any type) from manufacturers, that contained ROMs with handwritten labels, the handwriting on the labels was neat ('image is everything'). Even serial numbers done by marker pen were done neatly. I certainly would have expected that on a board that IBM knew may be photographed, IBM would have ensured that the handwriting was neat (and the labels themselves cut better).

* The patchwork of yellow wiring is the same as on two 5170 type 1 motherboards that I have access to.

* The two DIL chips dated '82 are similarly dated on two 5170 type 1 motherboards that I have access to.

* I wouldn't have thought that IBM would put a barcode label on a pre-production board, but I concede that they may have done so for tracking purposes.

Weighing that up, I think the board is simply an early type 1 board where an earlier owner has replaced the original IBM ROMs with AMI ones.
 
modem7 said:
...I wouldn't have thought that IBM would put a barcode label on a pre-production board, but I concede that they may have done so for tracking purposes...
Click to expand...

You know, when the first Steath jet crashed (at least publically) in California in 1985 (hey, we are talking close to the same timeframe), the spokeperson said something to the effect of:

"...the F-117 is not in production..."

I instantly saw through the falsehood...
 
eBay item 390024973091 - pre-production IBM 5170 motherboard is my listing. The information in the listing is correct. I was the editor of Personal Computer Age at that time and the board was in an AT given to me by IBM. I don't recall exactly when I received the unit, but it was early 1984. I had to sign a non-disclosure agreement and I had to agree to test the computer and report any problems prior to a writeup. As compensation for my work as a beta tester, IBM gave me the computer.
 
It turns out that one of the type 1 motherboards I have has an '82 dated 286 chip (I didn't look at the CPU before).
And the second DIL chip is dated '83, not '82 (must have been the poor light).
A picture is at http://members.dodo.com.au/~slappanel555/misc/P10100071.JPG

So unfortunately, the only thing that I can see that differentiates your motherboard from mine is the ROMs.

The first official BIOS for the 5170 is dated 10JAN84, and with you receiving the 5170 in early '84, that BIOS is probably what's in the EPROMs.
But maybe not.
The "256" on the EPROMs probably refers to the fact that the EPROMs are 256Kbit. But what would the "AMI" mean? American Megatrends Inc. wasn't created until '85. I thought that maybe what's on the label is "AM1256", but from what I see on the Internet, an AM1256 chip is a PWM step-down converter.

And obviously, because you don't have the ability to test the board, you can't send us the ROM contents for analysis.

I'm sorry to be the bearer of bad news, but apart from the ROMs, your motherboard appears to be an early type 1 board, just like mine.
And the look of the ROMs doesn't inspire confidence.

This is new information to you. Therefore, I think you should remove the references in your listing about the wiring and the '82 dated chips (unless you state that they are also found in production boards).

What would help your listing is the addition of something like, "I was the editor of Personal Computer Age at that time and the board was in an AT given to me by IBM.", including your name. Do you still have your copy of the non-disclosure agreement?
 
¨Skyrocket¨ in flight...

¨Skyrocket¨ in flight...

I´ve heard an IBM employee refer to a prototype that was at the end of the AT cycle, but previous to the XT 286. It was called the ¨Skyrocket¨, with a smaller ¨baby AT¨ motherboard (like the XT 286), but only DIP RAM chips (the XT 286 has a couple SIMMs plus DIP RAM). He thinks it was fairly well along to go to release, but then the project was killed.
 
Scribe,

The uncovered portion of ROM U27 is stamped.
There are 4 digits grouped together in the corner of the chip, and they are difficult to make out.
The digits appear to be "8749". Is that the case?
 
Thanks for your comments - very interesting. You've got me curious and, if I can find a few spare hours, I might try to get the board running. I probably have a compatible video card, but the power supply and monitor might be a problem.

You're probably right about the BIOS chips, they are likely EPROMs - I can feel a window under the label. Wish I could remember what's in there, but it has been too many years. I am also curious about the AMI (or AM1) designation, but I don't have a clue what it means. Even if American Megatrends had been in business then I don't think it would refer to them. Wasn't IBM still doing their own BIOS work at that time?

I was not aware that the production version of this board had the wire jumpers on the back, but I'm not surprised. The jumpers on this board are just too tidy and well engineered. That usually does not happen unless there is an intention to produce some quantity.

Looking at your photo, I can see that the board traces appear to be the same, but that is only a fairly small part of the board. Note that yours has the green lacquer coating which mine does not. Also, the screening nomenclature is very different. That does not mean that mine is not simply an early type 1, but neither does it mean that it is. Therefore, I think that I will leave the listing as-is unless someone can show me an identical board from a production unit.

Your suggestion about providing some more historical background in the listing is good. I'll probably do that.

I seriously doubt that I still have the NDA. Over the years I have discarded more and more of the PCA documentation. I doubt that the agreement has survived previous purgings.

Again, thanks for your comments.
 
The numbers are hard to make out since they are partially obscured by that "W" or "M" written in gold grease pencil. As nearly as I can tell it is

2?C256-2JI
LBO 8749

The first line is, IIRC, a standard EPROM part number. The second line I have no idea.
 
Welcome to the fourms Jack AKA Scribe. Glade you joined up, I look forward to you being active here, you have lots to bring to the table!


Scribe said:
The numbers are hard to make out since they are partially obscured by that "W" or "M" written in gold grease pencil. As nearly as I can tell it is

2?C256-2JI
LBO 8749

The first line is, IIRC, a standard EPROM part number. The second line I have no idea.
Click to expand...
 
Scribe, were you aware that a logon screen pops up when your listing is displayed? At least on my system, it does. If I click "Cancel", I get the photos, but it might scare some people off.

This might well be a pre-production board, part of a run intended for software firms and early clients. I'd expect an engineering prototype to look a lot rougher.

We were getting early pre-production 80286 steppings from Intel starting in '80 and they were always in ceramic LCC packages. Wouldn't it be reasonable to expect an engineering prototype to use them also?
 
Scribe said:
The numbers are hard to make out since they are partially obscured by that "W" or "M" written in gold grease pencil. As nearly as I can tell it is
2?C256-2JI
LBO 8749
The first line is, IIRC, a standard EPROM part number. The second line I have no idea.
Click to expand...
A few people will be put off by the "8749" because a group of 4 digits like that on chips was commonly (commonly, but not always) used to indicate the week of manufacture, e.g. 8749 would translate to the 49th week of 1987
 
Terry Yager said:
Could it be these guys?

http://www.amis.com/bookmark_404.php

http://en.wikipedia.org/wiki/AMI_Semiconductor_(AMIS)

--T
Click to expand...

Well AMI (American Microsystems Inc.) => AMI Semiconductor => ON Semiconductor, where "=>" means "got eaten by" has been around since 1966, but I don't think they were into EPROMs at that date.

It doesn't make any sense that someone would write the chip vendor's name on the chip. I suspect that they aren't original in any case. A peek at the underside of each as well as the contents would tell a lot.
 
Scribe said:
Looking at your photo, I can see that the board traces appear to be the same, but that is only a fairly small part of the board. Note that yours has the green lacquer coating which mine does not. Also, the screening nomenclature is very different. That does not mean that mine is not simply an early type 1, but neither does it mean that it is. Therefore, I think that I will leave the listing as-is unless someone can show me an identical board from a production unit.
Click to expand...
How about this one? The green wire is a repair I did.
http://members.dodo.com.au/~slappanel555/misc/P1010002.JPG
http://members.dodo.com.au/~slappanel555/misc/P1010003.JPG
 
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