Seiko Sii Caliber Vd77a Movement Holder

Seiko Instruments (SII) Caliber VD77A

Seiko Sii Caliber Vd77a Movement Holder

ManufacturerHattori aka Seiko Instruments Inc. (SII)
Caliber NumberVD77, VD77A
TypeQuartz
Lignes10.5”’
Diameter
23.7mm
Casing Diameter
23.3mm
Thickness
3.45mm
Battery Cell
377 (SR626SW)
Battery Life
~3 years
Frequency32,768 Hz
Quartz TypeTuning fork type quartz crystal
Stem0351 177 (351177) / tap 10
Hand Sizes1.20mm / 0.70mm / 0.20mm x 2
Jewels0
Driving System
Step motor
Hacking?
Yes
Anti-Magnetic
> 1600 A/m
FunctionsCentral hours; central minutes; small seconds subdial at 6:00; 24 hour indicator (also used as a day/night indicator) at 12:00
Country of ManufactureJapan
Known Models Android/Aragon Ultra Mini (Too many to list, please add your watch to the comments below…)

The Seiko Instruments (SII) caliber VD77A is a quartz watch movement with 0 jewels. Seiko refers to this family of movements as the “VD7 Multi-eye” series. This caliber has been around since at least March 2016, as that is the date on available technical documents.

Accuracy:

SII/TMI claims the caliber VD77A has an accuracy rating of less than +/- 20 per month when the watch is operating in the normal temperature range from -5 degrees C to +/- 50 degrees C.

Time Setting:

To set the time on the SII caliber VD77, simply pull the crown out one click. This movement only has time setting mode, so one click is all you can do. Set the hands forwards or backwards. With the crown pulled out on click in time setting mode, the seconds hand will hack aka stop. Press the crown back in when the desired time is displayed on the dial. The 24 hour subdial at 12:00 cannot be independently set, as this indicator follows the main central hour hand.

Battery Replacement:

A new battery in the SII caliber VD77A should last approximately 3 years. If you need to change the battery, it is possible to DIY. The battery number is 377 (DR626SW).

Seiko Sii Caliber Vd77a Battery Install

Crown/Stem Removal:

Look for the arrow with “Push” written beside it. Above this text is a tab with a small indentation. It is only in clear view when the crown is in the correct position, so there is no need to worry about which position to put the crown in when pressing the detent button/tab. Using your tweezers or a toothpick, gently push down the tab/lever while pulling out the stem.

Seiko Sii Caliber Vd77a Crown Extraction

Replacement Price:

At the time of this post, replacement prices for the caliber spec VD77A were found online in the range of $19.70 – 21.95 USD.

Technical Drawings:

Seiko Sii Caliber Vd77 Tech Drawings

Additional Resources

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Venus Caliber 178
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