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Legacy Technology RAM Boards - A Question for UK Modders.

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Pete W.:
Hi there, all,

I wrote 'all' but I guess this question is directed at UK Modders.

Back in August, 1980, I bought some printed circuit boards from the New Bear Computing Store in Newbury, Berkshire.  These boards, when populated, each supported 4 kB of static RAM, using 2102 or 21L02 chips plus some 'glue logic'.  The boards are physically similar in outline to those of the Motorola 'Exorciser' development system for the 6800 8-bit microprocessor.

Because of difficulties getting hold of other components for my project (e.g. a teleprinter as VDUs weren't available) I never assembled these RAM boards.  Amateur computer enthusiasts in those days didn't have access to stuff like keyboards, monitors and PSUs that have since become more easily available!

I still have both the boards and the 21L02 chips but I can't find any of the original New Bear circuit or assembly instructions.

So I'm posting this enquiry in case any other (UK) Modder still has any relevant New Bear documentation on file and would be prepared to copy or scan for me. 

John Swift:

Hi Pete

just incase no one has the instructions for the  New Bear Computing  memory boards
widen the search to include other computers of that period

without the complication of dynamic refresh the boards will use a simple address decoding circuit that is likely to be very similar to other designs published in ETI , Practical electronics etc

http://ece-research.unm.edu/jimp/310/slides/8086_memory2.html

  John

DMIOM:
Pete,

I can't help you directly, but there's another member - Trevor Brownen(sp?) - on here who might be able to give you some pointers. The gentleman's username on here is "trevoratxtal" and if I recall correctly he mentioned, in a thread when we were discussing NASCOM machines that he was involved (as the designer?) of systems in the 1970s and 1980s.

Dave

DavidA:
You could also try asking on the Geekstogo website. I have always found them very helpful.

www.geekstogo.com

Dave.

Pete W.:
Eureka!!!!

I knew, just knew, I must have the Newbear literature SOMEWHERE!!!

This afternoon, I searched through the filing cabinet and found it!!   :thumbup:   :thumbup:   :thumbup:  Halfway back in only the second drawer!

The search took quite a while but that was because I kept reading all the interesting long-forgotten stuff I wasn't looking for.   :ddb:   :ddb:   :ddb:

The schematic diagrams are on diazo dye-line print paper and have aged a bit but are still legible.  Maybe I'll have a go at re-drawing them in Fusion 360.

I got a 120 day warning when I started this reply but I thought I'd post anyway in case anyone else needs the data for these Newbear RAM boards.  Do you think a Google search for 'Newbear' would find this post?

Who knows how many milliamps 4 KB of 21L02 static RAM plus address logic would draw?   :lol:   :lol:   :lol:   :lol:   :lol: :lol:

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