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The 7906 (and derivative 79061 and 79261) is an automatic chronograph perpetual calendar movement produced by IWC based on the Valjoux 7750 ebauche from 1985 through 2016.
The Valjoux 7750 movement was extremely important to the resurgence of IWC and the basic design remains in use today. The company has used it for many important innovations since the 1980's, including a perpetual calendar, rattrapante, and grande complication. The 7750 ebauche was used for the 790 family of movements and the basic architecture is the basis for today's 69000 family of movements.
In 1985, IWC surprised the world with the introduction of an innovative perpetual calendar movement, Cal. 7906. Designed by the legendary Kurt Klaus, this movement was much simpler to operate than previous perpetual calendars and was reliable and relatively affordable as well. It began with a Valjoux 7750 ebauche before being disassembled and modified by IWC. The movement was refinished and plated with gold, then assembled and regulated by the company.
The original Cal. 7906 used a steel plate for the perpetual calendar module. Starting in 1987, IWC switched to a gold plated brass plate, renaming the movement Cal. 79061. Original Cal. 7906 movements were typically swapped out for this improved movement when watches were serviced by IWC. In 1996, IWC began using the Triovis regulating system rather than the original Valjoux Fine Regulator. This movement was named Cal. 79261 and is also swapped during service.
The Klaus perpetual calendar movement has remained in production for decades. As recently as 2016 IWC has produced new IWC Da Vinci Perpetual Calendar watches with this movement. A minute repeater variant, Cal. 79091 was introduced in 1991 for the Grande Complication, Ref. 3770, and a rattrapante version, Cal. 79251, followed in 1995 for the 10th anniversary of this movement.
- 7906 (1985-1988) - Steel plate
- 79061 (1987-1996) - Brass plate
- 79261 (1996-2016) - Triovis regulator
- IWC Da Vinci Perpetual Calendar 3750 (1985-2003)
- IWC Da Vinci Perpetual Calendar 8153 (1985-1989) - Diamond set
- IWC Da Vinci Perpetual Calendar 9252 (1985-2003) - With bracelet
- IWC Da Vinci Perpetual Calendar 9253 (1985-2001) - Diamond set with bracelet
- IWC Da Vinci Ceramic Perpetual Calendar 3755 (1986-1995)
- IWC GST Perpetual Calendar 3756 (2001-2004)
- IWC Da Vinci Perpetual Calendar 3758 (2004-2006) - Larger case
- IWC Da Vinci Perpetual Calendar Kurt Klaus 3762 (2007-2016) - Tonneau case
- Automatic chronograph perpetual calendar movement based on Valjoux 7750
- Bi-directional winding
- Hours, minutes, chronograph seconds central
- Date by pointer at 3 00
- Month by pointer and chronograph hours at 6 00
- Year window at 7 30
- Day by pointer and small seconds at 9 00
- Chronograph minutes and moon phase indicator at 12 00
- Ø 30 mm
- 39 jewels
- 21,600 A/h
- Power reserve 44 hours