The Acorn System Backplane

The Acorn System Backplane uses 64-way DIN41612 A/B sockets on a pitch of 25.40mm (1") and is 3U high.

The original backplanes were single sided and only the 32 A-side connections were made, the intention was that the B-side connections are wire-wrapped as required, typically card frame slots are then dedicated to a particular board.

On my replica backplanes I have also tracked all the B-side connections allowing any board to be fitted in any slot but this has to be done with caution because of the potential for shorting between signals on some boards.

The following table shows the backplane connections:

Acorn System Backplane

(also here as a pdf: Acorn System Backplane)

B-side signals on the following boards need to be considered when using a double sided backplane:

Generally those boards with extra port pins on the backplane will be OK as they default to inputs.

When using the 6502A CPU Board then the additional clock signals are required to drive various other boards. 

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