Delta 600, How Do I Remove Shower Cartridge/Mixer?

[Antlerman]

Please look at this picture and tell me how to remove this cartridge. Also am wondering if I'll be able to simply replace it?

 

[Terry]

The dome unthreads and behind that is the ball with springs and washers. Be careful not to "egg" the dome by pressing too tightly with pliers. I sometimes tap around the dome to loosen it up and spray oil can help too.