I recently acquired a watch with a PreciDrive/HeavyDrive movement. I know the marketing spiel for HeavyDrive: allows for more mass/unbalance in hands, and avoids problems from shocks by applying counterforce with the motor. It’s this second bit that fascinates me: does anyone have an idea how it actually works? The first thing that pops to mind is accelerometers but (and I’m not an engineer) it seems to me there’s no way you could monitor them within the power budget of a watch that runs for…
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…
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
Horological Institute of Japan and its journal
I have mentioned the HIJ a few times before, but my very first was in the cal. 2722 thread when I stumbled onto primary sources for the significance of te Citizen cal. 1930.
"The Horological Institute of Japan is the only academic organization sp…
Continue readingIn search for a GADA HAQ watch
I’m currently on the lookout for a GADA HAQ watch, preferably with a deep blue dial. At first, I thought about a Grand Seiko but lately, The Citizen watches have caught my attention.
Continue readingSo far I’ve got these watches on my list:
– Grand Seiko SBGP013G
– Citizen AQ4091-56M
– Citizen AQ4080-52L
Any other watches I should know about? Any swiss watches maybe?
Citizen’s first 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”…
Thermocompensation: Methods and Movements
In Pursuit of Perfection : Thermocompensated Quartz Watches and Their Movements
[NOTE: hedrick has rescued this from the Google cache. He is not the author. The original version was posted by Bruce Reding.]
The purpose of a watch is to correctly mark…
Continue readingJunghans AT-cut 4 Mhz movement(s) (and some of what came before)
The Junghans 667.26 is a 4 Mhz caliber that has been discussed here before:
1. When found in Doensen's book published 2006
2. A dedicated thread in 2014 by @sekunde
3. A…
Junghans AT-cut 4 Mhz movement(s) (and some of what came before)
Continue readingEnjoying my Longines V.H.P 36mm L3.316.4
Recently purchased new off of eBay. Some great deals there at the moment.
Continue readingNow looking into my next HAQ. Citizen or vintage Omega
I’d love to find a NOS Omega Constellation 1252.30.00.
Glad to join here and share my The CITIZEN AQ4091-56M.
I’m from China. It was difficult for me to join this forum. Because we can’t visit Google.com and thus I can’t pass the reCAPTCHA verification.
Recently, I’ve been choosing a HAQ watch.Because I’m tired of the errors of mechanical watches.
I’ve learned a lot of knowledge about HAQ from this forum, such as the principles of the movement, the mechanism of thermal compensation, etc. I’ve also seen many sharing posts from friends.
In return, I will also share my watch to everyone.
Continue readingRecently, I’ve been choosing a HAQ watch.Because I’m tired of the errors of mechanical watches.
I’ve learned a lot of knowledge about HAQ from this forum, such as the principles of the movement, the mechanism of thermal compensation, etc. I’ve also seen many sharing posts from friends.
In return, I will also share my watch to everyone.
I bought…
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