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Ebauches SA, MOSABA P1 – Prototype #6, 1965
Prototype category: experimental proof of concept
Description: Brass, aluminium and acrylic cased, experimental tuning fork movement in observatory competition configuration. Construction of the movement on a square, machined, brass main plate, which is part of the ‘layered’ construction of the prototype. Back cover built of brass strips with a glued in square, acrylic sheet. Back cover attached with four small screws to protruding columns from the main plate. Centrally placed, stainless steel, symmetrical tuning fork, crowned by two red coils. Tuning fork flanked right by the electronic stimulation and control system. On the lower right side a brown bakelite cover for the battery. Mechanical part housing the wheels on left side of the tuning fork, constructed with partial gilt, brass bridges cannibalised from an unknown mechanical movement. The indexing placed on the collar of the tuning fork towards left to activate the wheels then turning the hands. Circular window through the brass main plate allowing for observation of the indexing through the dial from the front. Small, circular white dial with black minute indexes, in the center with visible brass main plate. Large precision detection sticker at ‘6’. ‘Sandwiched’ square, acrylic sheet between brass main plate front and aluminium cover. Aluminium cover with eccentric, circular aperture for the dial. Applied brass ‘Ebauches SA’ logo on the front left, with applied #6 in the center. Silver coloured, shiny hands. Several hand written notes ‘0.9V’ with black sharpie. No crown.
Dimensions: movement overall: 50 x 50x 10mm
Movement: experimental MOSABA, tuning fork caliber, numbered #6
Additional Info: This is one of about 10 experimental proof of principles hand built in 1965, leading to the development of Ebauches SA‘s MOSABA caliber 9160 and 9162 in 1966. All components of the movement and the casing are numbered #6. Another version of these experimental pieces is known (#9), but it had survived only partially and is now lost since 2011, making this piece the earliest and for now the only surviving proof of principle for the MOSABA system. The indexing is attached just underneath the ‘collar’ of the left tuning fork arm. Latter construction will be abandoned and the indexing system will be mounted very low on the right hand tuning fork arm.
Electric Watch Prototypes 