Just to start at the 'beginning': are you sure the powerlead is properly in the socket at the back of the Avant ?
It looks like the powerlead is a fixed one but it isn't: it's a 8-figure 'standard' powerlead !
Since the problem started after pulling leads maybe accidentally this came out a bit ??
The old (er) Avants have the mains switch at the back, the later version below the screen (right side).