No ATC reception, VHF1 reception not selected

[LH4371]

All, yes I read the manual but it only says to push the Call button and pull that knob, yet I do not see that megaphone icon and can only hear myself transmitting to ATC. I can READ what ATC responds to me but cannot hear. How do I get that megaphone icon?

Pushed knob: x correctly shown

Pulled knob: zero nade niente

what am I missing?

 

[LH4371]

EDIT, must be one of these funny things. Just started a flight EKCH to EGLL and I DO hear ATC - though still no megaphone shown on the radio stack?!