ORSA Military Watch Battery Change

Yesterday I found that the battery of my ORSA Military watch has 'died'. Good opportunity for me to get into the watch and see what drives it. Also this is my second battery change, after the Guess watch some time ago. Out with the tools then.

The watch with the case back removed (battery as well). Note the tab that holds the battery in place.

The case back. The gasket is fitted to the case back and not the case. The gasket has been re-lubricated and the case back cleaned.

The watch is powered by an ISA 317 calibre. I believe that this is the ISA 317/30 calibre. There are a number of ISA 317 calibre in the series.

Basic specifications:

Size: 11.5 ligne, height 3.2 mm

3 hands, sweep second (70/120/20)

1 jewel

Variations:

ISA 317/10: no date

ISA 317/30: date at 3 o'clock

ISA 317/30-D6: date at 6 o'clock

ISA 317/40: day-date at 3 o'clock, height 3.6 mm

The movement ISA 317/30 is assembled by the Prestige Time Co Ltd. This company is part of the ISA Group (founded in 1958). The Prestige Time Co Ltd is based in Hong Kong. The ISA 317 contains Swiss parts and is labeled on the data plate as Swiss Parts/ China Movement.

The data plate on the movement.

Another view.

The original battery that comes with the module. I don't know if this standard industry practice, but quartz movement sold in Taiwan, all comes with a battery. This battery is made in Germany and is of the Varta brand. The battery is of the V371 type.

I could not find Varta batteries here in Taiwan, so the next choice is the Renata batteries. Renata batteries are Swiss made watch batteries. My local watchmaker was kind enough to give me this battery.

The battery in the movement. It is all well that ends well. No need to reset the movement, unlike some quartz movements.

I don't think there is a need to pressure test the watch as it is rated for 5 ATM. As long as the case back is tighten (but not too tight as to crush the gasket) and the gasket has been lubricated, I believe the watch would retain its 5 ATM water resist capability.