Led by good type with characteristic spirit, manage diagnostic device (11)
I believe the answer is:
stethoscope
'diagnostic device' is the definition.
'stethoscope' can be an answer for 'device' (stethoscope is a kind of device). I am not sure about the 'diagnostic' bit.
'led by good type with characteristic spirit manage' is the wordplay.
'led by good type' becomes 'st' (I can't explain this - if you can you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'characteristic spirit' becomes 'ethos' (I've seen this before).
'manage' becomes 'cope' (manage can mean to cope or do well).
'st'+'ethos'+'cope'='STETHOSCOPE'
Can you help me to learn more?
(Other definitions for stethoscope that I've seen before include "Doctor's instrument" , "Medical instrument" , "Instrument used in listening" , "listening device" .)