The Addams Family Tree - S1-E5
Audio problem: With Morticia in his arms, he says "And I dropped you...only once." If you watch his profile, you can see that his face never moves. Hard to believe especially when you know he had an animated face.
The Addams Family Goes to School - S1-E1
Audio problem: When Wednesday comes into the house crying her mouth isn't moving.
The Addams Family Goes to School - S1-E1
Audio problem: After Gomez suggests the rack for a stretch, he rings for Lurch. You hear Lurch say "You rang?", but his lips don't move.
The Addams Family Meets the Undercover Man - S1-E16
Audio problem: Ted Cassidy (Lurch) was an accomplished organist. However, when he "played" the Harpsichord, he was only miming the actions. When Lurch is playing while Gomez and Morticia are fencing the music doesn't match the movements of his hands.
Answer: Basically from what I understand, they stuck the innards of a small flashlight into the base of the bulb and put a little switch on it. When he put it in his mouth and bit down, his teeth would hit the switch, which would turn on the flashlight and made the bulb light up.
TedStixon