Ultimate Guide to the Heuer Digital Watches

Posted by: C11   |   20 May 2012   |   8 Comments  

Collectors often reflect on the 1970s as being the most dynamic decade in Heuer’s history, a case that’s easy to mount when you look at the combination of the ground-breaking Chronomatic movement and a roll-call of famous names-  Monaco, Carrera, Autavia, Silverstone and Montreal, to name but a few. The other reason that the 1970s stands out is that at the same time as Heuer was developing innovative mechanical chronographs, it was also at the forefront of high-precision digital quartz technology.

The interest in electronics was very much driven by Jack Heuer, who would go on to a long career in the electronics industry after leaving Heuer in 1982. Jack visited Silicon Valley in 1972 and saw first-hand the advances in Microchip technology.While Heuer launched the Microsplit 800 (The world’s first digital stopwatch) in 1972, it would take another three years for Heuer to use the technology in a wristwatch.

The Heuer digital era lasted only seven short years (1975-1982), but during this time there were some incredible watches launched. Back in 1975 it must have seemed that digital technology would be the next wave of watchmaking- and Jack Heuer had no intentions of seeing Heuer left behind in the digital race.


Broadly speaking, there are two generations of movements used during this period: the Heuer developed movements in the mid-late 1970s and the ESA analogue/ digital hybrid movement of the late 1970s/ early 1980s.

The first generation of Heuer digital watches uses a series of movements developed by Heuer in conjunction with its partners in Silicon Valley, and is comprised of:

  • Calibre 100: LCD/ LED Chronograph
  • Calibre 101: LCD, single display; time and date only
  • Calibre 102: LCD/ LCD Chronograph
  • Calibre 103: LCD/ LCD Chronograph (Ford RS)
  • Calibre 104: LCD GMT (Manhattan)
  • Calibre 105: LCD Chronograph
  • Calibre 106: LCD Chronograph version of Calibre 101
  • Calibre 107: LCD GMT (Senator)

The most technically innovative of the movements is the Calibre 100/ 102- the first solid-state digital wrist Chronograph ever made. The Calibre is made up of two separate chips driven by a single 32kHz crystal on a common circuit board (as you can see in the photo above).

The chips were initially made by a US company called Integrated Display Systems (IDS), with Heuer developing its own capability in 1977 when it created a specialist Microchip company called Heuer Micro-Technik SA (HMT).

What’s also obvious from the photo of the Calibre 102 is the fragility of the movement, most notably the exposed thin wires connected to the two chips…only one of these wires had to break for the watch to lose functionality, which explains why so few Chronosplits survive today.

This vulnerability was partly addressed on later movements, such as the Calibre 105 below, which provided better protection to the chips. There are very, very few people who know how to service and repair these movements today, and it’s certainly not something to try at home. The outstanding website Led-forever has some great information on these watches- certainly worth a read.

The rapid changes in technology and the economies of scale available in chip production meant that Heuer’s digital movements quickly became uncompetitive. The solution was to use the ESA 900.231, a combination analogue/ digital movement used by Heuer, Breitling and many others. ESA (Ebauches S.A) was the parent company of ETA, before a name change in the late 1970s saw all movements in the ESA group re-branded as ETA (for example, the Valjoux 7750 become the ETA 7750).

The design advances in the three years following the launch of the Calibre 100 are obvious, although these ESA movements are still fragile compared to the bullet-proof quartz movements of today.

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