The Twin Dilemma:
(ep 1) As the Doctor and Peri prepare to go out onto the asteroid surface, the Doctor hits something on the console (not the door control) and heads for the door. We hear the TARDIS door sound effect, but the door doesn't open. Which is actually for the best, because Peri says something else and the Doctor turns back for a few more lines, before going back to the console and hitting the real door control.
(ep 2?) The silver computer terminal in the safe-house on Titan 3 seems to be rather prone to
wobbling - an obvious example being after Peri spots the bomb ticking away outside the room, and the Doctor walks away from the terminal to have a look...
(ep 2) In the 'fight scene' between the Doctor and the Cybercontroller, the carpet on the studio floor (under the central console) gets kicked up and rather badly creased...
(ep 2) When Lytton stabs the CyberController, his "blood" gets splashed onto the camera lens...
(ep 1) After the TARDIS breaks down, the Doctor and Peri can be seen standing over the console
reading the manual, even though it is quite clearly just a book full of blank pages!
(ep 1) The Rani leaves the bath house to find the Master, and Peri sneaks in to rescue the Doctor.
Note that she takes special care to bolt the door on the inside after she enters. But when the Rani and
the Master return, they just walk in, the door being mysteriously unbolted...
(ep 1) When the second Doctor materializes the TARDIS on the research station, he and Jamie head for the TARDIS door, with every intention of leaving, but the door isn't open, nor has the Doctor gone to open it. He then quite conveniently remembers that he should "take the recall disk" from the control console. It was a prop needed for the story, so it wasn't just an excuse for going back to open the door (there is dialogue during this as well). He walks back to take it, and opens the door. Clever chap..
(ep 3) The knife Shockeye uses to stab Oscar has a surprisingly total lack of blood on it.
(ep 3?) When the Second Doctor is running to hail down the lorry, he slips slightly on the gravel of
(ep 1) Peri pronounces "Daleks" with an English accent.
(ep 1) Watch for the moment when Maylin Renner (one of the Karfellans) accidentally pulls a slider switch from the computer console. But being a professional, he quickly reattaches it without looking at it or drawing a great deal of attention to it..
(ep 1) The Doctor says he is travelling light this time after Tekker's enquiry as to whether Peri is his only companion. But the last time he was here (as the Third Doctor), he only had Jo Grant with him - so he was travelling light then, too..
(ep 2) After the robots have attacked and there are several unconscious guards on the floor, one of them quite noticeably shuffles his legs.
(ep ?) In one scene when the Doctor and Peri (or possibly Herbert) enter the TARDIS, as the inner
doors open, you can see one of them bounces off the console room wall and starts to close again..
(ep 2) In the very first scene - who is that guy walking past in the background?
(ep 2) When the DJ fires his ultrasonic gun the first time (to show Peri), he shatters the doors to his studio. Later, when the Daleks advance into the studio, the miraculously repaired doors open as they approach it...
(ep 2?) When those two chaps show a Dalek their security passes, you can see the head of the
Dalek operator through the "neck grille".
(ep 1) Peri pronounces "fireball" with a English accent.
(ep 1?) Nicola Bryant then goes on to pronounce "sterile" with a long "i", in a most un-American way.
(ep 1) At the end of this episode, a stone hits the Doctor too soon. He was supposed to be stoned for a little while before being hit, but one overzealous extra hit him too soon... (This was a blooper Colin Baker mentioned at a convention.) (sometime during Mindwarp [ep 5-8]) A bulb blows as the TARDIS dematerialises...
(ep 12) (last ep. of Terror of the Vervoids) This is very nitpicky, I know, but after the Doctor has destroyed the walking rhubarb, the camera shows a shot of him holding a leaf in his left hand... Cut to another shot, with Mel coming up beside him, and the leaf has magically moved to his right hand... (Or is that the other way round? Can't remember...)
(ep 12) When the Vervoids are dying, one of them is blatantly a person in a black sweat suit with a mask and a few leaves - You can even see the drawstrings to the pants!
(ep 9&12) (beginning & end of Terror of the Vervoids) Somebody moves the TARDIS around between these two episodes.... In episode 9, the bottom of the TARDIS is aligned with some yellow stripes on the floor of the Hyperion's cargo bay. In episode 12 however, the TARDIS is at an angle to these stripes...
(ep 14) Watch the scene where the Master and Glitz leave the Doctor in the console room of the Master's TARDIS. You'll note that Glitz and the Master distinctly leave the console room and go into another part of the TARDIS. However, the next time you see Glitz and the Master (talking about the Doctor's imminent switch into a "zombie"), they are definitely standing in front of the scanner screen in the console room. Someone didn't feel like building an extra set for another room in the Master's TARDIS!
(ep ?) One of the many times that the Doctor interrupts the Matrix's replay of events, you could hear what sounds like studio direction just before the replay begins again. Most of it is unintelligible, but "take 6" can be distinctly heard as the action fades in on the monitor screen. The question is - is this one of the technical crew, or is it simply one of the distinguished Time Lords in attendance being overly loud at the Doctor's trial? ;-)
(ep ?) The whole Trial season had quite a few sound problems... At several points in the story, the sound from earlier in the story is mixed in with the current sound. Like, there's one example I can think of later in the story where you suddenly hear, from out of nowhere, the Doctor saying, "Very good!" That was clearly from the beginning of The Mysterious Planet when Peri said something about there not being any birds or flowers or something. The Doctor then said "Very good!" to her. But, much later on in the story it shouldn't magically come back, obviously... Wonder whose fault that was?