Does the prayer of the muezzin become invalidated if he sits during the prayer to stop the noise coming from the loudspeaker or to turn off the wall clock that broadcasts the Adhan, then returns to complete his prayer, or is this action permissible because it is for the benefit of the worshippers?

The jurists agreed that excessive movement invalidates prayer, but they differed on defining what constitutes 'excessive.' The Hanafis and Malikis hold that excessive action is that which makes an observer doubt whether the doer is actually in prayer. As for the Shafi'is and Hanbalis, they consider the criterion for 'little' and 'much' to be common practice ('urf'). The Shafi'is believe that two steps or two strikes, or similar actions, are considered little, whereas three consecutive actions are considered excessive. The Hanbalis view 'little' as whatever common practice deems little, and that continuous excessive action unrelated to the prayer invalidates it, whether done intentionally, out of forgetfulness, or ignorance, unless it is due to necessity. As for scattered actions, they do not invalidate prayer. Based on this, if the action of this person is considered 'little' according to common practice, their prayer is not invalidated; but if it is considered 'excessive' according to common practice, then it is invalidated.