Bad news from daughter: Omega Constellation HAQ battery has leaked. Yes, I’m upset because it could have been avoided had she checked her watches on a regular basis as she was told? Kids!!!

Is it still possible to get a replacement 1680 (252.511)? From where, how much? If not, any suggestions for a drop-in replacement?

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.)

There is also a darker dial ENH-200. Catalog page shared by @Citizen _collector
[ATTACH type=”full”…

Citizen’s first digital TC movement, the caliber 1930

Once, pondering Citizen’s 1 SPY movement, I reflected upon the notion that, assuming you bought such a watch as an adult, you could likely wear it until death, and not have it gain or lose even a full minute – without adjusting the time. That seems a little mind boggling at first.

But then it raises the question, would anybody wear such a watch, and tolerate it being wrong by, say, 45 seconds? That seems unconscionable. For a non-time-lord, someone who isn’t a die hard HAQ fan, maybe it’d…

What is your tolerance for inaccuracy? And how to double the accuracy of any watch.

Hi all

It’s some time since I posted here. I hope someone can help with my question.

I have just acquired a new Longines VHP watch. When it arrived, the seconds were running 2 seconds fast, but I left it alone as I read here and elsewhere that the hands would auto-correct. Will they did, in a manner of speaking, as the second hand, when hacked, now sits at the 56 second marker. Also, although the time seems correct to the second, the watch is pulsing the minute hand at 06, 16, 26, 36…

Longines VHP Hand Alignment Question

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…

How does ETA HeavyDrive REALLY work?

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.

The system described:

1. Was motivated to make HAQ production more efficient by avoiding stray capacitance effects.
2. Is a…

Seiko 2-way inductive communication with HAQ calibers

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).

First 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