Macrotech S-100 Systems

This page lists the Macrotech S-100 docs I have, and some notes from Macrotech owners. This page last updated June 14 2020.

Photocopies of manuals listed here are available from me for a modest per page fee. Here is how to order S-100 stuff and email @ me. For a list of all S-100 docs click here.

List of Macrotech manuals

V-RAM (static) Macrodrive user manual, 300-321 or 300-324, July 1985, 54 pgs, scheamtics
MI-286 286/Z80 Reference manual, 30 pgs
MSR IIA or MSR 2A memory card Tech manual rev 1.1 1986, 56 pgs, schematics
MSR II memory card Tech manual preliminary 1984, 32 pgs
untitled, "MAX series dynamic RAM card" 36 pages
-- (note: for memory card, describe location of RAM and large 40-pin chip)
Product Guide for Alpha Micro, 1991 (some S-100 prod.), 20 pgs

The Macrotech MSR II board, has four rows of DRAM continuous across the board. The 40-pin DRAM controller IC is below all DRAM. The MSR-IIA board, has the 40-pin DRAM controller IC in the center of the board, with equal sets of DRAM to either side of that chip. I don't have an image of the Macrotech MAX card. Drawings describe an area on the lower left of the card J1, of five columns of four rows of jumpers.

George Michael Hart and the Macrotech MI386S

Michael George Hart discussed one of the Macrotech products in Usenet newsgroup "comp.os.cpm" in March 2009. It was part of a correspondence he had with an owner of a MacroTech 80386 S-100 board. He gave me permission to post the story here. His comments to me are below.

Here's a link to his Web site's description of his work on restoring an IMSAI with some Compupro boards.

- Herb Johnson

"You are free to use my story as you desire. But remember this all happened in time period between start of 1989 and the end of 1989, since the article I did with regards to the Macrotech MI386S board was published in the Spring 1989 Issue of SuperiIcro [magazine]; I actually have a copy of that issue. I keep it around for remembering the my participation in the IEEE-696 technology. Anyway, please qualify the story as being told to the best that my memory, given how long ago it happen". - Michael George Hart

I am certain the board [you showed me] is the Macrotech MI386S satellite board. It is not a s-100 permament bus master. It should have a full megabyte of 32 bit wide dual ported 100 ns 4-way interleaved dynamic RAM, a 16Mhz 80386 and a socket for an optional 80387 math coprocessor.

The reason I know of this board is I worked with Macrotech testing and eventually writing an article for the Spring 1989 issue of "Supermicro, Journal of VME, MULTIBUS, and S-100 systems" titled "RUN MS-DOS AS AN S-100 SATELLITE TASK"

In those days I had a LOMAS DATA Thunder 186 board that [was] very much a single board PC that you could place into your S-100 system. It had connectors for VGA, floppy and keyboard along with if I recall correctly 512K static RAM. Able to boot CCDOS and MS-DOS. At the time [the] board was state of the art. That board's claim to fame, at least the reason why I bought it, was it passed the IBM PC compatibability test, which at that time was the ability to run MS Flight Simulator. I had this board in my very first IMSAI-8080 with modified front panel. I've been looking for another one for many years now.

[In any event,] the first set of MI386S boards worked flawlessly. I initially had one of those and based my article and software for the article on that board. For some reason late in the writing of the article, Macrotech had me exchange that board for another MI386S with a different revision number. In retrospect It was probably because they no longer knew how to make the newer releases of the MI386S function reliably. It was my understanding [that] the engineer who originally designed the board had left the company. At the time I speculated he took with him some nuances about what was need in all those PAL's on the MI386S board to make if function reliably. They needed that original board to reverse engineer the PAL's. [But] I am only guessing here.

The new board had a number glitches and after them sending me several replacement PAL that they hoped would have fixed the boards problem I think they realized they had a serious reliability issue with the MI386S. I completed the article and it was published in the spring 1989 issue of Supermicro.

Initially I could have purchased the board at at a significant discount because of my article. I never bothered, since at that time the boards I had never functioned reliably after the swap out with the initial MI386S given to me for the article. I just assumed by the time the article was published, they would have the board released to the public at large [as] functional and reliable.

After the article was published I got a call phone call from who I think was the owner of LOMAS DATA PRODUCTS. She told me that a number of clients were having difficulty with their MI386S and they made a point of citing my article to the fact that their MI386S board should also have worked with their LOMAS DATA PRODUCT boards.

Apparently Macrotech were selling boards with the same issues I [had] when writing the article. It seemed that no one at the company had stressed tested board in the [Concurrent DOS] environment. At the time they were pushing the idea that the board worked great in a Concurrent DOS environment. I guess lot of their customers were disagreeing with them.

Anyway, I told the owner of LOMAS DATA of my experience with the board, which must of spread like wild fire and killed the product and I think Macrotech for that matter since I never saw a whole page add having to do with the Macrotech 386 Satellite board again and for that matter any Macrotech product after 1989.

This happened many years ago. I am only telling the story as best as I can remember it. But has always bothered me that I may have killed a company even if they were selling a product that simple did not work reliably.

So if you actually have a MI386S board that actually works you do have one of the rarest of [Microtech] IEEE-696 boards around. But if you don't have the documentation that may be rarer yet. :-)

Later, Michael.

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Herb Johnson
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