Seiko’s technology for battery-powered clocks with sweeping seconds

From a survey of the literature, Seiko has used two methods:

1. In 1996, Seiko published one method involving a spring and a viscous damper:
“we adopted a method in which a third wheel, whose gear and pinion are elastically connected by a coil spring, and a fourth wheel, whose rotational load is applied by the viscous resistance of grease, are installed in the gear train”

The spring…

Seiko’s technology for battery-powered clocks with sweeping seconds

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Catalog of Citizen A660 A010 A060 0100 HAQ models

This is a running catalog of all known watches with Citizen’s caliber 0350, A660, A010, A060 and 0100 high accuracy quartz movements. It is provided in PDF form for offline viewing. The intended audience are those interesting in acquiring one of these watches.

Please jump to post #60 for latest version 2.0 (Mar 2025).

Original text
I have scoured the web for days to build the following list in the Citizen forum. If I have…

Catalog of Citizen A660 A010 A060 0100 HAQ models

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The specially adjusted 9F models

@BrianBinFL and I have assembled the following list of the 9F watches, which halve the usual 10 seconds a year tolerance to just 5 seconds a year through special adjustment at the factory. Most feature a ‘gold star’ on the dial, but not all.

From newest to oldest they are:

1. SBGP017 in 2022, the ‘Shinshu Sea of Clouds’ for the 55th anniversary of the 44GS case; with 9F85 and display back
[IMG width=”500px”…

The specially adjusted 9F models

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