ESA 900.231 Module and Repair
In the late 1970's Heuer decided to stop producing their own digital watch modules and started using Swiss modules produced by a company called Ebauches SA. The module Heuer specifically chose was the ESA 900.231 sometimes referred to as the ESA Y2 900 231 movement. Heuer continued to use the ESA 900 231 movement up until around 1983.
The ESA Y2 900 231 module is a 7 jewel analogue digital movement (ana digi) offering the following features:
The ESA Y2 900 231 module was used and common to the following Heuer chronographs.
*Heuer also produced an alarm version of the Verona which has a very similar ESA 900.911 movement fitted.
As well as Heuer a number of other high end watch manufacturer's utilised the ESA Y2 900 231 module in their watches and these include:
Last but not least:
It also worth mentioning that the ESA Y2 900 231 module was used by other including Bulova and Yema to name a few.
Collectors and repairers alike often try to source module from these watches with very mixed results which I discuss on the next page under faults