That's true, If if recall it correctly on ours they were on a daughter board which bridged across the top of 2 of the main boards in the rack, the main boards being about A3 size full of things like half adders, implemented in DTL logic. Then out came TTL 7400 series and someone redesigned it all onto A4 size boards (or whatever the sizes were in those days, my rememberer ain't what it was.
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