new find: an Intel MDS 800

From: Dwight K. Elvey <>
Date: Wed Oct 27 12:08:51 2004

>From: "Scott Stevens" <>
>I recently acquired an exciting new (old) machine, an Intel MDS 800,
>known as the 'Blue Box.' It's the 1975-era 8080 based box that kicked
>off CP/M.
>My particular machine was intended as an 8051 ICE box, it has the 8051
>emulator pod and external PROM programmer.
>The system came complete with a big box of what appears to be complete
>docs and a lot of software on 8" disks. There are four or more
>different versions of IRIS, a disk labeled 'CPM' which I hope is a
>boot disk, and multiple versions of other Intel tools, including the
>targeted 8051 development tools.
>I paid a fair amount for this system, and am going to go slowly at
>bringing it up. It's been stored a long time and there's a troubling
>amount of surface rust on some of the screw heads and exposed
>I've popped it open and some of the ICs (mostly TTL) have corrosion on
>the leads. I have a few opening questions for others who have
>restored hardware in similar condition: should I remove the corrosion
>on IC leads, or do I run the risk of 'removing' the leads. The
>circuit boards look really good, so worst-case I will replace some of
>the chips.

Hi Scott
 First, make sure you can find a replacement device and then
wiggle or squeeze the lead a little with some needle nose.
If it crushes or fails, replace the chip. The problem is that may
IC's used iron cores and the solder plate would actually
cause electrolysis and rot the core out of the lead.

>What is the opinion about this kind of servicing? The chips in
>question are all (so far as I have investigated) common 7400 series
>(some Schottky) TTL gates. Do people consider it as 'damaging' to the
>'credentials' of a piece of classic hardware to replace chips with
>others with significantly different date codes?

 I rate making it work more important than date codes.
Still, most often when I buy onesy-twossies, I get them
from some surplus place and they have old date codes anyway.

>This is going to be a long term project for me, I fear, because I want
>to do it right. This machine has a built-in CRT display so I might be
>forced to do some (something I almost always refuse to do these days)
>video monitor troubleshooting.
>The machine has a built-in 8" floppy, which I assume is the
>low-density original, and an expansion case (third party) with two
>newer and higher density drives.
>Is there a source for new or NOS 8" floppies out there? One thing for
>certain that I'll be doing early after getting this machine up and
>running is a backup of all the media that came with it (a fair amount,
>probably 30-50 disks, many of which are Intel branded originals).
>Lots more questions and comments likely to come on this project.

Hi Scott
 I used to use both the Series II's and the MDS800's as well
when I worked at Intel in the late 70's. I wrote some code in
both assembler and PL/M. Both the Series II and the 800's could
run the same software. Of course, if the software was for
a '86 processor, you'd need a board with that on it.

 When looking at the boards, don't confuse the IOC board
with the main processor for the system. The IOC board has
a 8085 on it but it only runs the various I/O functions. The
main processor will be one of the cards on the multi-buss
slots. The main processor could have been a 8080, 8085 or
a 8086. This all depends on what it came with.

 I have both a Series II and a MDS800 at home but I've not
found time to play with them. I can only play with one at a
time. They are on my list to play with. I have a number of
disk ( about 60-80 someplace ) and a pile of documents.
 I still need to catalog what I have but not gotten to it.
 One thing that would be great, would be to find the bits
and pieces that make up the user library. There was a
lot of good stuff there. I have some listing from the library
and may have information on disk as well but like I say,
I just haven't gotten to them yet.

 Also, Joe, I think I have an extra Series II keyboard. Since
I've not had a chance to check things out, I may only have
one working unit. Still, these are really good keyboards
and are not likely to have problems. They use the hall effect
switches so there is no mechanical problems other than the
Received on Wed Oct 27 2004 - 12:08:51 BST

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