Repeated element of solo on organ is musical (6)
I believe the answer is:
oliver
'musical' is the definition.
(musical based on Oliver Twist)
'repeated element of solo on organ' is the wordplay.
'repeated element of solo' becomes 'o' ('solo' has two O's).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'organ' becomes 'liver' (liver is a kind of organ).
'o'+'liver'='OLIVER'
'is' acts as a link.
(Other definitions for oliver that I've seen before include "Musical from Dickens novel" , "stage show" , "Paladin (with Roland)" , "First name of Dickens boy Twist" , "-- Reed, actor" .)