Visible crew/equipment: In the episode where Carl is "fishy sitting" for his boss, Steve is explaining to the boss how he swallowed the fish. You can clearly see the studio lights reflected in Steve's glasses.
Rock Enroll - S5-E13
Visible crew/equipment: Towards the end of the show when they bring the cake out for Steve a crewmember walks past on the right of the screen.
Visible crew/equipment: When Eddie drives his car through the front door, when they show the hole he made with the car, look at the very top of the screen, the sky stops and you can see a good two-three feet of sound stage.
Rock Enroll - S5-E13
Visible crew/equipment: When they are singing happy birthday to Steve near the end of the episode, a crew member can be spotted in the top right corner walking past an open door. (00:20:55)
Visible crew/equipment: When Urkel throws the baseball at the lamp, the shadow of the boom mic can be seen moving from right to left on the wall that the closet door is on, and then moves back in the opposite direction until it is pulled out of view as Carl screams "What happened!?" (00:22:22)
Answer: It is said that as Steve Urkel became a more popular character on the show, Judy became less important to the storylines, plus either her or her parents were demanding more money, causing her to be removed from the show entirely.