Checked again to find one end broken (6)
I believe the answer is:
reined
'checked' is the definition.
(to rein something in is to control or check it)
'again to find one end broken' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'to find' says to put letters next to each other.
'one' becomes 'i' (Roman numeral).
'broken' indicates an anagram.
'end' is an anagram of 'ned'.
're'+'i'+'ned'='REINED'
(Other definitions for reined that I've seen before include "Stopped or slowed a horse" , "Pulled in, checked progress" , "Restrained" .)