Somebody once discovered Chase buzzer's broken at the base (3-4)
I believe the answer is:
has-been
'somebody' is the definition.
Both the answer and definition are singular nouns.
Maybe there's an association between them I don't understand?
'discovered chase buzzer's broken at the base' is the wordplay.
I cannot really see how this works, but
an anagram of 'base' is 'asbe' which is located in the answer.
The remaining letters 'hen' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'once' is the link.
Can you help me to learn more?
(Other definitions for has-been that I've seen before include "Banshee who has become a failure" , "One whose time is past" , "Banshee (anag.)" , "Person no longer of consequence" , "One who's past it" .)