Memory Boards

The Centurion system originally had a 4k core memory setup. As the company grew and technology evolved, this got upgraded to a 16k DRAM board, then a 32k DRAM board, and then ultimately to the 128k DRAM board shown here. The 4k, 16k and 32k boards were only compatible with the CPU4 system (maybe, it seems a 32k was used with a CPU5), and the 128k boards were only compatible with CPU5 and CPU6. Further, the CPU6 allows two 128k boards to be used for a total of 256k memory. This is achieved through use of the 16-bit memory address and two(?) additional bank/page switching bits.

128k Memory Board

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Schematic

This schematic is the amazing Meisaka's reverse engineering efforts on the Memory board. This schematic is very much so a work in progress, but it is an amazing start.

32k Memory Board

The 32k Memory Board is one of the few 4-layer boards Centurion ever produced. Initially, Centurion was using Fedder sourced 16k DRAM boards, however these had some notable issues that were causing problems. As such, Centurion designed this 32k DRAM board as a replacement for the Fedder boards. The 4-layer design was to rectify the issues they were seeing with the Fedder 16k boards. This is just the third board that Centurion ever designed in house, the first and second being the DSK/AUT and DSKII cards.

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Schematic

There is no schematic for the 32k memory board as yet