This PCB was listed as a 'mystery item' on our website, with users encouraged to provide information.  The following is a summary of the info provided:

We received the following from Peter Moores:

I have worked on this type of board some years back and it looks like a driver board from an Elliott Automation Arch 1000. The reason I believe this is that the predecessor system the 803 and 803b had encapsulated AND OR gate logic in an item called a Minilog i.e. a logic brick. These never had transistors in but the Arch 1000 (if I remember correctly) had the same logic brick layouts with up to sixteen connections but un-encapsulated and had the first germanium transistors

We are grateful to Peter Moores for this information

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"As a student I had the chance to work at a retired Elliott Arch 1000 process control computer (1971).

It had 8k of 18 bit wide core memory, 1 accumulator (today we call it register), an instruction set of 13 instructions (an early risc computer).

It had a very simple operating system (monitor), hard wired by a diode matrix (less than 100 instructions):

It checked 4 switches of the switch register in order to
* jump to routine A

* jump to routine B

* execute a binary loader

* ??don’t remember??

The Arch 1000 was used for continued control in a production plant in chemical industry, I have no further details.

The boards I remember were larger in size, (higher) than shown in (Driver Board).

They had encapsulated Minilog circuts (mainly containing 2 NAND gates with 4 inputs and an extension input, with one germanium transistor for each gate).
The minilogs were mechanically fixed by solder balls, and connected by wires (no printed circuits)."

From Werner Uelpenich