Earthshock - S19-E6
Audio problem: In episode two, the Cyberleader misses a button on his console, yet we still hear a beep...
The Moonbase - S4-E6
Audio problem: If you listen carefully to the soundtrack of part four of "The Moonbase", some 'chatter' and 'feedback' from the floor manager's headphones can be heard. (At the time this particular episode was recorded, there was just a one-week gap between recording Doctor Who and transmission, so there was no time available to re-record the episode, and this mistake had to be left in).
Audio problem: In episode 1, the Doctor hits something on the central console (not the door control) and walks towards the door. The door doesn't open, but the sound of the door opening is still heard.
Audio problem: Before the TARDIS materialises in the haunted house, you can hear The Daleks' time machine sound effect for no apparent reason.
The Invasion - S6-E3
Audio problem: The first victim of the hypnotic signal stops walking when he hears it, but the sound of his footsteps continues for several seconds afterwards.
Resurrection of the Daleks - S21-E4
Audio problem: Davros' lips don't move when he says, "Now for The Daleks," just before he releases the Dalek-killing virus.
The Dalek Invasion of Earth - S2-E2
Audio problem: In episode 2 you can hear the Black Dalek clear his throat before speaking.
Audio problem: When Irongron fires his first gun, the sound is heard before the gun actually fires.
The Daleks' Master Plan - S3-E4
Audio problem: At one point where the trail of Visian footprints are appearing, we hear the sound effect of the foot hitting the ground, but the footprint fails to appear.
The Dalek Invasion of Earth - S2-E2
Audio problem: When the Doctor says that what they're seeing now is the middle period of Dalek history, you can hear a metallic thing being dropped off screen.
Audio problem: In episode 2, the Kandyman's microphone picks up quite a bit of the Doctor's dialogue by accident.
The Dalek Invasion of Earth - S2-E2
Audio problem: When the Dalek says to give the Doctor and Ian the test, it cuts to the prison cell where you can hear a Dalek voice that gets cut off.
Audio problem: When Chinn tells the Brigadier of his agreement with the Axons, the movement of the actors around the set causes various loud wooden clumping sounds that are rather inappropriate for the organic interior of Axos.
Audio problem: In episode 3, when the dog is barking at Sam's house and is abruptly silenced (apparently by an Auton), the sound is obviously not a dog barking. It sounds a bit like a man pretending to be a dog, and going "woof woof" not very convincingly.
Audio problem: In the first scene with the Dalek Supreme, the lights on its dome are way out of synch with its speech.
The Trial of a Time Lord 13-14 (aka The Ultimate Foe) - S23-E4
Audio problem: All of the scenes of the trial have some sort of sound problems. Among other things, sound bites from earlier on appear from seemingly nowhere, and, if you listen carefully, you can hear someone calling out the cue "Take 6", which should have been edited out quite easily, but wasn't.
Audio problem: When the Doctor arrives at UNIT HQ in his stolen car, he speaks to a guard. We see close ups of the guard twice...but watch the brief clip of the Doctor (Jon Pertwee) between the two and you can just see that his lips aren't moving even remotely in synch with the words. (In fact, it is just a repeat of the previous shot of the Doctor, with new lines dubbed in).
Audio problem: The music accompanying the closing credits fades down part way through (at a different point in each of the four episodes) and simultaneously fades up at a different point, the net result being a rather disjointed-sounding edit.
Audio problem: When the Doctor chops a brick in half, you can tell that the brick is really made from balsa wood by listening to the sound it makes when it hits the ground.
Audio problem: When the companions are returning to Earth via the pillar of smoke, you can see and hear each person walk up the steps and then supposedly disappear. Unfortunately, you can then hear them walk down the other side of the steps..
Answer: It was never destroyed on-screen; it was intact at the end of the TV movie, and destroyed by the start of the 2005 series. It was destroyed in the novel "The Ancestor Cell," but in a completely different manner to what happened in the series.
DaveJB