24 May 1990
Williamson and L-J visited Ferranti again and noted a statement from Worroll that
included his final assessment on the composition of PT/35(b), which was that:
(1) the board was single sided, there being no evidence of through hole plate connections;
(2) the board was one ounce copper clad FR4 epoxy glass laminate, 1.6mm thick, with 9 layered glass cloth, 7628 type, 9 layers being more popular in Italy;
(3) solder mask was applied to both sides of the board, the solder mask apparently being a wet epoxy based type either screen printed or more likely brushed onto the board, the reason for coating both sides of a single sided board being a mystery;
(4) he gave measurements of small tracks;
(5) he stated that the tracks were coated with pure tin probably from an electroless tin solution, presumably to aid solderability;
(6) normal electronic grade solder (60-65% tin, the remainder lead) was used to make the solder connection to the pad;
(7) the etch profile on the copper pad and tracks suggested it could be home-made, but the machined radius of the board suggested commercial machining operation.
These conclusions were also listed in DC11674 (prod 357), a letter to Williamson from Worroll dated 24 May 1990, which has attached to it handwritten notes of Worroll. In Williamson’s ch10 CP dated 1711/99 he stated that Worroll’s view as that the fragment had solder mask on both sides, but that none of the other scientists who carried out such analysis agreed with him. As stated elsewhere, in his own CP Worroll said there was only solder mask on the reverse of the board.
L-J’s CPs add nothing to the above. One thing of note is that during the precognition
process L-J referred to his notebooks (which he kept, despite the majority apparently
having been destroyed) and these were seized as productions 1765 and 1766. His
notes do not add anything to the above either.
The only point to note is that in his introduction to these enquiries (prod 1765, p74), it suggests that the fragment of circuit board had been found in PI/995 by Allen Feraday at RARDE. It was of course Dr Hayes who was recorded as having found the fragment. The notebooks do also mention enquiries L-J made about the MST-13 timer on 14 and 15 August 1990 (see under the relevant date, below) and re Senegal and the interview of Jean Collin.
Note that L-J only signed the police labels for PT/35(b), DP/11 and DP/31 on 27
March 1992, as arranged by Buwert (S4949U).