When you enter Stage A, take a right and enter the small office. It's by the desk.
Check the control room directly across from the office to find another atop a console.
Found in the windowed room in the southern part of the stage. Slip through the vent to find this in a back corner.
Found in the other windowed room on this end of the set.
Atop some crates in a room in the southwestern corner of the set. Get to it by crawling through the vents.
Found on a couch as soon as you enter.
There's a vent next to the same couch that leads to a storage room. There's another jack in the box back here.