Small Spring That Can Ruin a Vintage G-Shock Crystal

The alarm spring found in vintage Casio G-Shock modules 240, 691 and 901 is responsible for more damaged crystals than many collectors realize.

 

The spring presses against the inside of the crystal, exactly where the conductive silk-printed pattern is located. If the module is installed slightly out of position and then twisted into place, the spring can scrape the silk print from the inside of the crystal. The damage will be clearly visible from the outside and is often impossible to repair completely.

 

The safest method is to position the module correctly before pressing it into place. If it needs adjustment, remove the module straight out, reposition it, and install it again. Avoid twisting the module while the alarm spring is in contact with the crystal.

Many collectors place a small piece of conductive carbon tape where the alarm spring contacts the crystal. This provides some protection against mechanical wear while still allowing the electrical connection required for the alarm to function. 

The alarm may become slightly quieter, but it will usually continue to work normally.