ISA Caliber 2331/103 Watch Movement

Manufacturer	ISA
Caliber Number	2331, 2331/103
Type	Quartz
Lignes	11 1/2”’
Diameter	25.6mm
Height	2.95mm
Jewels	0
Battery Cell Number	371 (SR920SW)
Current Consumption	U=1.55 V T=25 C, Typ. 0.85, Units uA
Battery Life	66 months
Hand Sizes	1.20mm / 0.70mm / 0.20mm
Stem	401/1610, tap 10
Hacking?	Yes
Functions	Central hours, central minutes, central seconds, date at 3:00 or 6:00
Country of Manufacture	Far East Assembly (China?)
Known Models	Invicta Russian Diver 0554 (Add your watch to the comments below…)

ISA caliber 2331/103 is 0 jewel quartz movement. The tech sheets on this caliber are dated as far back as 3/11/09. This movement is discontinued as ISA is no longer producing movements.

Some of the topics covered in this caliber listing:

Estimated Battery Life:

ISA claims that the power reserve from a fresh battery is approximately 66 months. There is a power save or hacking function that is engaged when the crown is pulled out to time setting position.

Installing a New Battery:

There is a metal tab with a hole holding the battery in place. You will need to carefully place your tool in the hole on the tab and gently slide it over. This will allow the battery to be released. When installing a fresh battery cell, wedge it under the lipped edge near the VSS stamp on the movement, then press down (with rodico or while wearing a finger cot), you must also be holding the tab to the side until the battery is pressed completely down, then you can allow the tab to slide back over the battery where it should have enough resistance to hold it in securely. (Similar ISA caliber 2330 is shown below as an example.)

Battery Reset:

After replacing the battery, you may need to perform the following reset procedures:

From ISA:

After battery insertion, or if movement does not work correctly after battery setting, a reboot can be carried out by connecting the indicated capacitor with metallic tweezers. This operation is far better than removing and reinserting the battery and thus ensures a correct restart of the movement. After that, the movement is in the same configuration as after a battery change and an initialization procedure has to be carried out as described previously in this instructions manual.

Replacement Price:

At the time of this post, this movement was found at replacement prices of $12.95 – 16.95 USD. It should be noted that although this movement is listed in the catalogs of many watch parts suppliers, they may not actually have it available since it is no longer being produced.