Crook is not working (6,4)

I believe the answer is:

broken down

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'crook is not working' is the definition.
I can't tell whether this defines the answer.

'crook is not working' is the wordplay.
'crook' becomes 'broken' (I am not sure about this - if you are sure you should believe this answer much more).
'is not working' becomes 'down' (down can mean broken or not working).
'broken'+'down'='BROKEN-DOWN'

Can you help me to learn more?

(Other definitions for broken down that I've seen before include "Analysed" , "worn out" .)

I've seen this clue in the Sydney Morning Herald.

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