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Chronosplit -- Main Page

Heuer introduced its revolutionary Chronosplit chronograph in 1975. The first version of the Chronosplit (Reference 100.703) featured an LCD display for the time-of-day and an LED display for the chronograph functions. The LED (chronograph) proved to be problematic in several respects, including the battery consumption required to power the red display and problems with the LED multiplexing. Becuase so many of these early Chronosplits were returned to Heuer for repair, Heuer quickly changed the design to incorporate a second LCD display for the chronograph function. This second version of the Chronosplit was the Reference 102.703.


A.Reference 100 (Early)

(LCD / LED)

B.Reference 102 (Later)

(LCD / LCD)

C.Ladies Ref 101.703


D.Ladies Ref 106.703


F.Ford Split Lap Unit 77

Here are some "fun facts" relating to the Chronosplits:

  • The early Chronosplits (LCD / LED version) were assembled by a group of Heuer watchmakers, working in Montgomeryville, Pennsylvania. As such, these may be the only Heuer chronographs made in the United States. Electornic components came from suppliers in the United States, primarily a company called "Solid State Scientific"; the cases and other certain other components were shipped in from [to be added].

  • Heuer manufactured approximately 200 of the early Chronosplits (LCD / LED) for Tiffany & Co.. Based on the poor performance of these chronographs / high failure rate, Tiffany never placed a second order for the Chronosplits. Accordingly, the surviving Tiffany Chronosplits are very rare.

  • In addition to Tiffany's, Heuer also manufactured Chronosplits for Ferrari (both the early and later versions) and for the German Army (Bundeswehr).

  • The early Chronosplits (LCD / LED) included 11 separate circuits, using three different printed circuit boards.

  • Heuer manufactured a special version (LCD / LCD) for Ford Motorsports, which is called the Split Lap Unit 77. These rare watches do not carry the Heuer name or logo, but there is a Ford logo, displayed by LCD.

  • [More to be added]

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