Transmitter never working at front of room (5,4)
I believe the answer is:
nerve cell
'transmitter' is the definition.
(I've seen this before)
'never working at front of room' is the wordplay.
'working' indicates anagramming the letters.
'at front of' is a charade indicator (letters next to each other).
'room' becomes 'cell' (cell is a kind of room**).
'never' is an anagram of 'nerve'.
'nerve'+'cell'='NERVE-CELL'
(Other definitions for nerve cell that I've seen before include "it provokes sensation" , "transmitter" , "excitable signaller" , "Neuron" , "conductor" .)