How to remove the back of the calibre 83? There is no notch at all

Hi Siduch.

I would go to a watchmaker near by. They use a wooden or plastic tool to open the caseback without scratching it.

BR

The Calibre 83 has a screw-down case back, not a snap-on one so there’s no notch.

To remove it:

Use a case back wrench (Jaxa-style or adjustable) that fits the back’s slots.

Secure the watch in a case holder to avoid slipping.

Turn counterclockwise with steady pressure.

If it’s tight, a bit of case-back tape or rubber ball can help with grip.

If you don’t have the proper tools, it’s best to take it to a watchmaker to avoid scratching the case or damaging the gasket.