He's called on to help with current problems (11)
I believe the answer is:
electrician
'he's called on to help with current problems' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he's called on to help with current' is the wordplay.
I cannot really see how this works, but
'current' could be 'electric' (synonyms) and 'electric' is present in the answer.
'he' could be 'ian' and 'ian' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for electrician that I've seen before include "Sparks (informal)" , "Sparks (slang)" , "Installer of wiring, etc" , "he might shed light?" , "One doing wiring, etc" .)