Zodiac astroquartz - how to open?

[Khan]

Hi 

How to I access the case back? I want to change the battery. I'm able to unscrew the the east and west screws but the north and south screws are sitting super tight. There are some kind of pins positioned on the backside of those screws. 

[jdm]

You have to remove the other 4 screws, in fact the ones that you removed do not reach the caseback. Refit them and tighten reasonably, that could relieve some force on the other screws. It could also be that someone had placed glue or other stuff to make life harder for others, try heating them a bit with a soldering iron. You need a well fitting and perfectly dressed driver to avoid damage to the head, some sensibility is also needed to avoid snapping the head with excessive force.

[watchweasol]

Hi   jdm is right some one may have used glue or loctite so the soldering iron to the job  and be careful.      good luck.