The Processor Technology 4KRA Static Memory board was a welcome relief for many who struggled to get the original MITS 4KB dynamic boards working. You didn't have to worry about those pesky refresh cycles with a static memory board.

The 4KRA is arranged as a single block of 4KB of memory, the memory address can be set to any multiple of 4k using jumpers to augat pins. Processor Technology advertised it as a 'low power' board even though it draws .9 amp from the +8v supply. 32 memory chips in the 91L02 family are used on the board. This board was priced at $159 as a kit ($195 assembled) on the March 7, 1977 Processor Technology price list.

I ran a 30 minute memory test on this card on 05/15/99 and it passed with flying colors. Currently the memory address is set to 0d000h but it can easily be changed without any soldering.

I built this card myself from a kit many years ago. "PRCO 4KRA" is etched on both sides of the card. There is no revision or serial number on it. The original Assembly and Test Instruction manual is included.

If you'd like to see the original Processor Technology sales sheet for the 4KRA, click on these links:

• Picture of the 4KRA Caution this image is 80KB in size!
• Specifications Caution this image is 138KB in size!