Lucas Nascom Small Lynx Electronics Gemini Small

RAM 'A' - 4K / 32K DRAM Memory Card

Description

A world shortage of 4118 devices forced Nascom to supply memory via DRAM memory card (RAM 'A').  The card was capable of taking either 4027 devices to give 4K (cheap) or 4116 devices to give 32K (Not cheap!).  The card also featured EPROM sockets to take 2708's giving 4K of space. 

Running at 4MHz, this card often featured an unpleasant effect.  Memory would become corrupt at random intervals.  This phenomena  was so well recognized it became known as 'Memory Plague'.  The root cause was identified as he lack of buffering between the card and the NAS-BUS leading to noise getting into undesirable effects.  Solutions involved changing chips, adding extra decoupling, changing pull up values and additional grounding. 

Any working board encountered today has probably been fixed by now!

Technical Details

Documentation

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RAM 'A' - 4K / 32K DRAM Memory Card

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