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).
Other mistake: Ian has completely forgotten the distinctive shape of a Dalek. It's only when the Dalek starts speaking that Ian says to the Doctor, "that voice". Yet later when they are at the saucer, he talks to the Doctor about the new back of the Dalek having a disk on them now.
Add timeMatty W
Factual error: Davros comments that, between them, the Daleks are carrying half a megaton of explosives - in other words, roughly twenty-five times more explosive force than the Hiroshima or Nagasaki bombs. An explosion of that size should cause enormous destruction (vaporizing everything within roughly two kilometers), yet when the Doctor detonates them they explode with about as much power as a small stick of dynamite each.
Character mistake: The Doctor gets Jo to do some mathematics to distract her. At one point she says "49 x 2=88", when it actually equals 98, then she says that "adding 10 equals 108". (In other words, Jo (Katy Manning) fluffed her line, got one figure wrong, then went back to script...).