Some piano maintenance (6)
I believe the answer is:
tuning
'some piano maintenance' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tuning that I've seen before include "Adjusting a musical instrument" , "Adjusting, to receive radio signal perhaps" , "This fork is used to adjust piano notes" , "Adjusting the pitch of an instrument" , "doing this to find a station" .)