Seiko Caliber 6N52

The Seiko caliber 6N52 is a 3-hander analog quartz movement. It is made in Japan and has no jewels. Timepieces with this movement feature a calendar date at 3:00.

Accuracy Rating:

According to official Seiko documentation, they claim that the average monthly rate the 6N is less than +/- 15 seconds per month under normal conditions (source). With regards to the 6N52, “normal” temperatures should be within the range of 5°C ~ 35°C (41°F ~ 95°F) for the best accuracy, however, the movement can still operate between -10C ~ 60C (14F ~ 140F).

6N52 VS 6N52A:

While you may see this movement mostly being referenced as 6N52, you may notice that the movement in your watch is engraved with 6N52A. The letter at the end of the caliber number is basically a version number. The main caliber number is 6N52 and A is the first version. At the time of this post, there is only one version. Therefore, “6N52” is the same as “6N52A”. So far, there is not a 6N52B or 6N52C.

6N52 VS 6N42:

There is a similar caliber 6N42 which shares many of the same specs as the 6N52 being discussed on this page. The 6N52 is considered an evolution of the 6N42, however, Caliber Corner has still not confirmed the main differences. Replacement 6N42 movements are available for sale from watch parts suppliers, whereas the 6N52 is not. Similarly, tech sheets for the 6N42 are available here, but the 6N52 technical communications have not yet been released.

6N52 vs 6N53:

There is also a similar Seiko caliber 6N53. The main difference between these two movements is that the 6N53 has a day/date at 3:00 and the 6N52 only has a date.

Changing the Battery:

The battery cell number in the calibre 6N52 is SR621SW / 364.

Below is a video of changing the battery in a similar cal. 6N42 movement.

Below is a macro image of the battery slot with the battery cell removed. Note that there is no need for an insulator tab.

Examples of watches with this movement:

The images on this page are of a cal. 6N52A found in this 140th Anniversary Limited Edition 140th Anniversary Sapphire model (ref: 6N52-00E0).

Caliber Commentary:

As originally posted on the @calibercorner Instagram page:

A lot of quartz movements still in use today are outdated, but the modern Seiko caliber 6N52 has a few design choices that standout compared to its Swiss (and even some entry level Miyota) counterparts.

Things to appreciate:

⚙️ The distance between the battery and the coil, means less likely to slip your tool against the cool. ⚙️ The protective insulator over the coil, means even if you do slip your tool, you probably won’t damage the coil!

⚙️ Easy press-in battery cell holder. No screws to lose; no battery straps to fly across the room; no friction arm 2mm away from an exposed coil ‍♂️

⚙️ No use of an insulator tab under the battery, just plastic that is already built into the movement.

Any watch technician can certainly appreciate coming across a layout like this when changing batteries all day! If you’re going for an affordable quartz, consider a watch with the 6N52A.⌚️

Here is an image of the red coil insulator/protector mentioned above:

• Official Seiko instruction manual (pdf)
• Tech sheets/drawings will be added as soon as they are available