Seiko Caliber 7t62

Seiko Caliber 7T62

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Seiko Caliber 7t62

Manufacturer Seiko
Caliber Number 7T62 / 7T62A
Type Quartz
Diameter 12”’ (24.1mm x 27.6mm)
Thickness
3.3mm
Jewels
0
Battery Cell Number 395/399 (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, central chronograph seconds, split time, 60 minute counter, date, alarm
Country of Manufacture Japan
Known Models Seiko Velatura (add more in the comments below)

This Seiko caliber 7T62 (actually marked 7T62A) was found in a Velatura model watch here. This quartz movement was made in Japan and features an alarm and chronograph. It is a 0 jewels movement. The caseback has a Piezo attached for the alarm tone (part 4589 801).

7T62 vs YM62

You may also see a similar caliber known as the Hattori or SII YM62. The YM62 is basically the same movement as the 7T62 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 than the 7T62 (see here).

7T62 vs 7T92

The caliber 7T92 is another popular Seiko quartz chronograph movement. These two calibers are sometimes mixed up. The big difference is that the 7T62 listed here has an alarm and a 1/5 second chronograph that measures up to 60 minutes. The 7T92 has a 1/20 second chronograph that measures up to 12 hours. The 7T92 does not have an alarm.

7T62 vs 7T32

You may see other collectors refer to the caliber 7T62 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 7T62 does not have an AC button or hole.

Chronograph Function

The chrono hand on the 7T62 pulsates 5 times per second. This also allows this movement to measure 1/5 of a second when using the chronograph feature. To reset the central chronograph hand: pull the crown to position 2 and hold the bottom chrono pusher until the hand is at 12:00. Long pressing will make the hand advance faster.

Alarm / Second Time Zone

The 7T62 has an alarm function that doubles as a second time zone subdial. The alarm can be set to ring once in the next 12 hours. To set the alarm, pull the crown to position 1 then press the bottom pusher to advance the alarm time. when you get the time you want, push the crown back in.

Accuracy

Seiko claims that the caliber 7T62 will maintain accuracy of +/- 15 seconds per month at normal operating temperatures of about 41F to 95F. The alarm is accurate to +/- 1 minute.

Replacement Price

Replacement prices of this watch movement were found online in the range of $65.95 – $71.99.

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 or if the alarm rings more than 20 seconds 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 or 399 cell.

Resetting the Chronograph Hand to Zero

There are two hands related to the chronograph function: The central 1/5 second hand and the stopwatch minute hand subdial. To reset the chronograph hands to 12:00 or zero on the dial, first pull the crown out to position 2 (2 clicks to time-setting mode). Hold the top chronograph button for about 2 seconds until the stopwatch minute hand turns in a full circle. Now use the bottom chrono button to advance the hand where you want it (holding the button will make the hand advance faster). Press the top chrono button again to switch to adjusting the big central seconds hand. Press the bottom chrono button to advance the hand to where you want it. Push the crown back in.

More watches with this movement:

Please share your experience with the caliber 7T62 in the comments below…

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Sam G
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Sam G

Online, this movement seems to generally be regarded as very reliable. The only issues I have come accross with it are as follows: 1: Chronograph not responding to *any* input from pushers after battery change (often running until it times out). Potential causes (My believed cause): Watch sat with leaky battery and corroded/oxidized the B (lower) pusher contacts. While actuating presser B, watch the lever that moves within the recessed area for the battery. Use a loupe or other strong magnification to check for corrosion. Potential fixes: Use a very small amount of alcohol with a brush to clean the… Read more »

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[…] caliber YM62 is based on the Seiko caliber 7T62. It is found in non-Seiko branded watches. It may be a possible replacement for the 7T62, however, […]

JJ
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JJ

In the battery compartment of the 7t62A what is the Orange tab and its purpose. In my seiko that Orange tab has turned to dust exposing a small circuit. Should that have contact with the battery or with the gold like prongs the connect to the battery? or should that circuit be insulated from both prongs and battery. Even after a battery change my trusty Seiko is not working because that orange tab disintegrated when removing the battery

Watchgeek
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Watchgeek

Are you talking about the translucent brown thing? It’s called an insulator. If yours turned to dust then it’s likely that it crystallized and disintegrated due to an old leaking battery. I hope someone corrects me if I’m wrong but I think they use them in these quartz movements to protect against improperly touching part of the movement that could cause it to short circuit. Based on the pic with the tweezers, it looks like the order should be 1. gold prongs at the bottom, 2. insulator in the middle, 3. battery on top. Are you sure you didn’t short… Read more »

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