Some time prior to 3 September 1990
In Williamson’s memo to the SIO dated 3/9/90 he summarised the various enquiries
that had been conducted in relation to the timer fragment, including the visit to Washington on 22 June 1990 and the link to the timing device.
He records a detailed description of the timing device, then lists the operating components displayed on the printed circuit board.
It is apparent that the various details he lists relating to each of the components must have come from enquiries conducted after 22 June 1990 but before the date of the memo.
He lists details of the manufacturer of the Nymph Quartz crystal, the integrated circuit boards and the relay switch.