Seiko Caliber 7t92

Seiko Caliber 7T92

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Seiko Caliber 7t92

Manufacturer Seiko
Caliber Number 7T92 / 7T92A
Type Quartz
Diameter 12”’ (24.1mm x 27.6mm)
Thickness
3.3mm
Jewels
0
Battery Cell Number 395 (SR927W)
Quartz Type Tuning fork type quartz crystal
Frequency
32,768 Hz (cycles per second)
Driving System
4 part step motor
Stem 351580 (tap 10 )
Hacking Seconds?
Yes
Hand Sizes 1.10mm / 0.65mm / 0.20mm for chrono and subdials
Functions Hours, minutes, small seconds at 9:00, central chronograph seconds, chronograph hours and minutes at 6:00 (up to 12 hours), 1/20 seconds at 12:00
Country of Manufacture Japan
Known Models Seiko SNDC33, SNDC31 (add more in the comments below)

The Seiko caliber 7T92 (actually marked 7T92A) is found in some Seiko branded chronograph watches. This quartz movement is made in Japan and features a 12 hour chronograph stopwatch function. It is a 0 jewels movement..

7T92 vs YM92

You may also see a similar caliber known as the Hattori or SII YM92. The YM92 is basically the same movement as the 7T92 except that it is sold to other watch companies and used in non-Seiko branded timepieces. Learn more about Hattori/SII/TMI/Epson here. It may be possible to interchange these movements, but the height is slightly taller (3.7mm vs 3.3mm) than the 7T92.

7T92 vs 7T62

The caliber 7T62 is another popular Seiko quartz chronograph movement. These two calibers are sometimes mixed up because they appear to be so similar – even the diameter and height are exactly the same. Both calibers even share the same technical guide.

The big difference is that the 7T62 listed here has a 1/20 second chronograph that measures up to 12 hour. The 7T62 has an alarm and a 1/5 second chronograph that measures up to 60 minutes. The 7T92 does not have an alarm.

7T92 vs 7T32

You may see other collectors refer to the caliber 7T92 as an evolution of the original 7T32 quartz movement, however, keep in mind that one huge difference between the two movements is that after replacing the battery, the 7T32 required performing an AC (or all clear) reset by using a wire, tweezers, or a paperclip to touch the positive side of the installed battery with the AC contact (there will be a hole labeled “AC” with an arrow). The caliber 7T92 does not have an AC button or hole.

Chronograph Function

The chrono hand on the 7T92 pulsates 5 times per second. This also allows this movement to measure 1/5 of a second when using the chronograph feature. There is also a rapidly spinning 1/20 second hand at 12:00. To reset the chronograph hands see below.

Accuracy

Seiko claims that the caliber 7T92 will maintain accuracy of +/- 15 seconds per month at normal operating temperatures of about 41F to 95F.

Plastic Parts

From the Seiko tech sheets:

Caution for disassembling: The hour wheel is made of engineering plastics. When pulling out the hour hand, take care not to damage the hour wheel.

Replacement Price

Replacement prices of this watch movement were found online in the range of $73.95.

Battery Change

In the manual, Seiko claims that the battery should last approximately 3 years. Keep in mind that the battery will drain faster if you leave the chronograph second hand running – specifically if the chrono is used for more than 2 hours per day. There is also a low battery indicator which will cause the small second hand to jump every 2 seconds. Low battery mode also prohibits the alarm from sounding off. The time on your watch will maintain accuracy even in low battery mode.

The original battery in the watch was also made in Japan by Seiko. The size is SR927W which should convert to a 395 cell.

Resetting the Chronograph Hand to Zero

There are four hands related to the chronograph function: The central 1/5 second hand, the stopwatch 1/20 second hand (subdial at 12:00), and the stopwatch hour and minutes (subdial at 6:00). First pull the crown out to position 2 (2 clicks to time-setting mode). Holding the top chronograph pusher (button A) for 2 seconds will select the 1/20 second hand. Pressing A again for 2 seconds will select the central chronograph hand. Pressing again for 2 seconds will select the hour/minute hands. You will know which hands you are about to adjust because it will turn in a full circle.

When they hand you want to adjust is selected (after it makes a full circle), use the bottom pusher (button B) to advance the hands forward until you get it reset to zero. To skip to the next hand, simply press A again for 2 seconds. When all of the hands are set the way you want them, press the crown back in against the case to position 0.

Caliber Drawing

Seiko Caliber 7t92 Drawing

Additional Resources:

Please share your experience with the caliber 7T92 in the comments below…

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