High tension on apparatus is OK (5)
I believe the answer is:
right
'ok' is the definition.
(I've seen this before)
'high tension on apparatus' is the wordplay.
'high tension' becomes 'ht'.
'on' is a charade indicator (letters next to each other).
'apparatus' becomes 'rig' (I've seen this before).
'ht' after 'rig' is 'RIGHT'.
'is' acts as a link.
(Other definitions for right that I've seen before include "Due" , "Factual" , "Privilege" , "Starboard side" , "Spot-on" .)