Polaris Caretaker 5 port - Not popping up and missing screen

[Ampsonic]

I bought a new home with an in ground pool, and I have slowly but surely been teaching myself about pool maintenance. Recently my popups have stopped popping up. If I bypass the caretaker I get excellent flow out of the other pool returns. By switching between the bypass and the caretaker, I can sometimes get it to run through one cycle of popups, but it gets stuck before completing a full circuit. I removed the union above the caretaker as I read there should be a screen/filter to clean, but there is no filter or screen present. When the pop ups are stuck, pressure on the gauge reads between 20-30PSI and the filter pressure goes up as well.

Questions:

• Should/can I remove the caretaker and attempt to see if there is some sort of jam?
• The sellers of the home included a home warranty that also covers pool/spa. What does a professional repair of this system usually cost?
• Should I order a replacement filter for the union or is there a reason it might not be there?

Here are some photos of the caretaker setup

 

[Ampsonic]

Update: I went ahead and took the caretaker apart. This was made difficult by the fact that the nut was inside the brick wall a bit (I’m guessing previous owners built this wall after the pool went in.) After a bit of chiseling I was able to get some pliers in there and got it loose.

The pistons inside were very worn, so I bought a rebuild kit and it all seems to be working great now!