KIM Uno /PiDP-11 plans...

Johnny Billquist bqt at
Fri Oct 23 10:27:29 CDT 2015

On 2015-10-23 14:39, Dave G4UGM wrote:
> I think that the switches can be found, but they might be expensive. I have
> a few that I used on recent project.
> What I found hard was obtaining centre off switches as it appear from this
> picture:-
> und-at-Attic-What-is-this
> that PDP-11 Switches may be flipped up or down, or is that not true?

Not sure what you mean by that. The switches only have two positions, 
though. They are either in the down position, or in the up position.
Some were spring-loaded and returned to the original position when you 
let go of them.

However, if you were to consider all the switches in one line as being a 
neutral line, most switches moved up from that position, while a few 
moved down. Think of them as being mounted upside down, perhaps?


> I believe they were made by C&K who are still in business. I wonder if it is
> worth approaching them.
> The double pole version appears to be still "stocked", I see Farnell  has
> some in the UK
> 4163
> 440?ost=7203J50&categoryId=&categoryName=
> but they are a tad expensive in the US....
> .. still working out how to build a front panel for his SBC6120 as FPC6120
> kits are even more un-obtainium than the switches....
> Dave Wade
>> -----Original Message-----
>> From: cctalk [mailto:cctalk-bounces at] On Behalf Of Noel
>> Chiappa
>> Sent: 23 October 2015 12:49
>> To: cctalk at
>> Cc: jnc at
>> Subject: Re: KIM Uno /PiDP-11 plans...
>>      > From: Alexandre Souza
>>      > Easily done if I had the original part on hand
>> We have plenty of the original bezels, from which it would be easy to cast
>> molds (the same part is used on the 11/45 and 11/70, unlike the rest of
> the
>> front console).
>> The real issue in any front panel recreation is going to be the switches
> (not
>> the plastic toggles, the actual electrical device). Both the /45 and /70
> used the
>> now-apparently-unobtainium version with the intergral metal plate to hold
>> the switch in place in a metal holder plate. So a recreation front panel
> is going
>> to have to have some new mechanical design, to allow use of standard
>> micro-switches - and that's probably going to mean a re-design of the
> plastic
>> toggles, as those attached to side-plates on the original toggle switches.
>> (That's all a bit difficult to describe in words; a picture will make it
> obvious, if
>> anyone wants to know more.)
>> I wonder how big an order of switches would be required before some
>> switch-making firm could be convinced to do a run? Maybe whoever made
>> the 'back in the day' still has the tooling to do so gathering dust in an
> old
>> room....
>>      > From: David C. Jenner
>>      > How about making a version for a REAL PDP-11/70 front panel, and one
>>      > for a REAL PDP-11/45 front panel, for those of us who have such
> stashed
>>      > away waiting for the right simulator to come along...
>> To do that is going to require exactly emulating the interface to the CPU,
>> which is not going to be entirely trivial. Physically, the signals all
> come over
>> flat ribbon cables to standard Berg connectors, so that won't be hard, but
> I
>> doubt the interface is documented, someone will have to puzzle it out by
>> reading prints - and probably looking at a working one with a logic
> analyzer.
>> Also, powering the front console requires an unusual AMP connector shell,
>> although that may still be available? And of course one could always bodge
>> the power connection...
>> 	Noel

Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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