Melody right for radio (5)
I believe the answer is:
tuner
'radio' is the definition.
('tuner' can be a synonym of 'radio')
'melody right' is the wordplay.
'melody' becomes 'tune' ('tune' can be a synonym of 'melody'**).
'right' becomes 'r' (common abbreviation).
'tune'+'r'='TUNER'
'for' is the link.
(Other definitions for tuner that I've seen before include "Adjuster of pianos" , "Radio adjuster" , "Radio receiver" , "Piano adjuster" , "piano man?" .)