MDS II/III Keyboard on eBay

[Vale, Martyn]

 

There’s an MDS II/III Keyboard on eBay at a fairly reasonable price here:

 

https://www.ebay.co.uk/itm/157234852068?itmmeta=01K2CVT8WRN9SYE7EMMA8BQD68&hash=item249bed70e4

 

I’ve bought a couple of items from him and he’s very helpful and good quality stuff as well.

 

Be quick as there’s been loads of views.

 

Martyn.

[Jon Hales]

Hi Martyn

Thank you for the information about the eBay.com auction. I don't intend to spend more on Series II parts. And I think I should soon have an extra keyboard.

One check I've made is that all the key mechanisms have a magnet that activates a 'good' module.

I'm making progress with sorting out the problems with some of the hall-effect modules - and hope to have all of this done by Thursday. As you advised, re-flowing solder is the solution in many cases. There are a few modules where I think I the hall-effect chip may be the problem. I have enough parts to deal with this using spare PCBs, installing new hall-effect chips and eventually moving the four pins from the units that seem OK in other ways.

Continuity checks have been the main strategy to locate soldering that needs to be re-flowed. A check has been to compare continuity between the pad on the PCB (where this is clear for a probe) and the soldered 'pin' that eventually will be soldered to the baseboard. Then, if continuity isn't found at the pin of the hall-effect module, it's clear there is a problem in the solder between the latter pin and the PCB. I'm finding it quite easy to add flux and a little more solder.

I have written to Martin Eberhard to ask if he can supply the 'kit' for a 1702A programmer. If so, I'll probably buy it during a visit to the US in a bit over a month from now. Do you happen to have a 1702A programmer? If so, would you be able to help (or allow me) to program the 8 EPROMs for the Intellec 8 monitor during your visit on Thursday? 

Not having that set of EPROMs programmed has delayed making the replica operational. And Craig, as of course he is entitled to do, has skipped the video he had said he would do on the I/O PCB - which remains relatively undocumented.

See you later this week.

Best regards

Jon

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[Jon Hales]

Hi Martyn

Martin Eberhard replied promptly. So, I shall have the PCB and microcontroller to build a 1702A programmer - in due course.

Best regards

Jon

[Herbert Johnson]

I've seen MDS keyboards on eBay every few or several months, for some
time. Often they appear to sell for a few hundred dollars. There's
vintage keyboard enthusiasts who buy them, possibly for the keyswitches
or for modern use as intact, could be either. Less often, to support an
actual Intel MDS.

That's what seems to set a price of a few hundred dollars as
"reasonable" - keyswitches and the general look/feel.

Occasionally there's been discussion about replacing the keyboard with
something modern. Simpler to replicate the keyboard interface protocols,
than to replicate the case and down to the keycap layout. I don't
recall if someone amongst us has completed a replication of either kind
(and documented it).

Regards Herb

On 8/11/2025 11:29 AM, Vale, Martyn wrote:
> There’s an MDS II/III Keyboard on eBay at a fairly reasonable price here:

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Herb Johnson, New Jersey USA
http://www.retrotechnology.com or .net
preserve and restore 1970's personal computing
email: hjohnson @ retrotechnology dot com
or try later at herbjohnson @ comcast dot net

[Vale, Martyn]

 

Hi Jon.

 

Sorry I don’t have a 1702A programmer, although I do have a board for one I’ve not got round to building yet !

 

I dropped the Car off this morning, so I’ll let you know when I’ll be picking it up an visiting you as soon as I know.

 

Thanks

Martyn.

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[Jon Hales]

Hi Martyn

Thanks - It's no problem that you don't have a 'completed' 1702A programmer. 

I'll be here all day on Thursday, except perhaps for a walk in the morning.

Best regards

Jon

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[craig andrews]

Hi Jon, 

I find Martin’s 1702 programmer to be overly sensitive in its failure triggers.  Frequently it rejects a programming cycle due to some voltage level tripping an error, so I have to take the eprom to another programmer.  The same chip programs just fine in a pro-log programmer or on a MIL MOD8 programmer.

And, yes, I still need to dig into and document with a video the intellec  I/O board.  It is taking up precious bench space. 

Regards

Craig

On Aug 11, 2025, at 9:04 AM, Jon Hales <jonh...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/CANPXPJnRjvMky3J7xxcLG-1eVBN0tS385cPxDHKUyunPK4kbqw%40mail.gmail.com.

[Herbert Johnson]

I don't follow Martin Eberhard on a daily basis, but he's got some chops
and has been around for some time. I humbly suggest some Web searching
to see if problems of the sort you mention, have been discussed already.
Possibly his documentation mentions something. I poked around and
there's discussions in the group

https://groups.io/g/AltairComputerClub

where he's active to the present day, this being a ten-year-old project
of his. Among those posts, some mention was made about replacing
resistors with trimpots, to adjust to some voltage specification. The
programmer has D/A's and possibly D/A's.

OF course Jon contacted Martin to obtain a programmer, that's a point of
contact. Apparently, I can't find any Web site where Martin offers the
programmer or documents about, other than posts here and there including
in the above-noted group.

Old programmers are kind of sledgehammers to EPROMs, so I'm sure they
can jam plenty of electrons into 40, 50 year old silicon with high
voltage. It's fun to read today how some folks still use (their
original) Intel development tools to program 1702's. I have a Pro-Log
M900 myself for the purpose, but I also bought an ancient 8080
breadboard, if only to read 1702's. There's also the Intel UPP, I don't
think I have the 1702 module.

Regards Herb

On 8/13/2025 12:58 PM, craig andrews wrote:
> Hi Jon,
> I find Martin’s 1702 programmer to be overly sensitive in its failure
> triggers.  Frequently it rejects a programming cycle due to some voltage
> level tripping an error, so I have to take the eprom to another
> programmer.  The same chip programs just fine in a pro-log programmer or
> on a MIL MOD8 programmer.