Are you using FotRSU still? These pix are from it. It would be similar in most mods or Stock:
In the Office January 11, 1943 - checking the SJ-I on the left, regular SJ on the right
Kept the regular radar
Exterior view just outside of Pearl, "supported" radar mast.
Inside the Command Room, hovering over the Radar Station button, and then Clicking it once.
So, you can either click the left button (FotRSU) and it takes you to the screen, or if you click that first Station button
above a 2nd time, it takes you to the A-Scope view by default. But you still have that left button that should take you to the PPI scope.
... and the view of the PPI with "Sweep" set.
Now, if you are in a different mod, the PPI might not be available. In other mods, and in FotRSU, if an upgrade fails in any form, the radar usually fails also, but then the A-Scope does not run either. But even if the radar does not function, or the PPI is not "active" in the modded game yet, you should still be able to go to the station. You just would not be allowed to turn the SJ on...
