NYTimes:
A small but growing movement of ankle-watch acolytes has been afoot for a couple of years, as various users of Apple Watc…
Citizen’s first digital TC movement, the caliber 1930
original title: Exceed ENH-205 with caliber 1930
Vintage find with Citizen’s first thermocompensated movement, the cal. 1930. (But not necessarily the inaugural watch model of 1981.)
Continue readingVintage find with Citizen’s first thermocompensated movement, the cal. 1930. (But not necessarily the inaugural watch model of 1981.)
There is also a darker dial ENH-200. Catalog page shared by @Citizen _collector
[ATTACH type=”full”…
Wearing AW on ankle
NYTimes: “
A small but growing movement of ankle-watch acolytes has been afoot for a couple of years, as various users of …
70s and 80s Citizen quartz service manuals
I have obtained a set of 40+ year old of service manuals, guided to the listing by @CitizenPromaster. Thank you, sir.
The service manuals consist of 4 binders. Pages are cardstock, clearly made to last. There are also overleaf pages for complex diagra…
Continue reading2024 Seiko patent applications for electronically regulating mechanical watches (both SD and non-SD types)
EDIT: there are two Seiko applications, taking different approaches. See post #7 for the SD-type one.
Below is the non-SD type:
Here is a new US patent application (October 2024 publication) I found while looking for Spring Drive patents:
…
Continue reading2024 Seiko patent application for an electronically-regulated mechanical watch (not SD)
Here is a new US patent application (October 2024 publication) I found while looking for Spring Drive patents:
Continue reading
It is NOT Spring Drive as we understand it, because there is still an escape wheel (#21 in the illustration) and a pallet fork (#22). There is however something more than a balance wheel (everything to the right of #22).
And it is NOT necessarily a quartz regulator. There is only a ‘speed governing mechanism…
2024 Seiko patent application for an electronically-regulated mechanical watch (not SD)
Akio Naito interviews
The better one is with Time & Tide: Akio Naito, President Seiko Watch Corporation | INTERVIEW
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Another…
Akio Naito interviews
Continue readingSeiko 2-way inductive communication with HAQ calibers
Miyahara (2003) Development of a non-contact annual deviation accuracy and guarantee system appears to describe Seiko’s factory regulation, adjustment and diagnostic system for HAQ mass-production.
Continue reading
The system described:
- Was motivated to make HAQ production more efficient by avoiding stray capacitance effects.
- Is a…
Seiko technical paper on the 9RA-series Spring Drive
Solely due to the generosity of @CitizenPromaster , I have come across a gold mine of technical information on Seiko’s 9RA second-generation Spring Drive movement in the form of a 14-page Japanese-language technical paper published by the Japan Horological Society (日本時計学会) in their journal メカトロニクス (translates to ‘Micromechatronics’)
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Out of respect for possible copyright, I will not (yet) post the entire paper…
The 1995 Japanese Industrial Standard for HAQ and its fatal flaw
JIS B 7025 in its 1995 edition is the current Japanese standard for ‘accuracy indication’, i.e. how makers may advertise the accuracy of quartz watches (and clocks).
Continue readingFirst the good news
At the tier of ‘annual accuracy’, the JIS mandates that manufacturers measure three things:
1) Temperature variation Vt
2) Aging variation Va
3) Battery voltage drop variation Ve
These are added together and…
The 1995 Japanese Industrial Standard for HAQ and its fatal flaw
