TACAN mode glitch

[Lixma 06]

This happens both from cold and hot starts.

 

If you hit the TCN button on the EHSD you seemingly enter TACAN mode (the UFC and ODU display all the right things) but you can't enter any digits on the keypad.

 

 

You have to turn TACAN mode off and then on again to input numbers.

[Tricky11]

I always press clear 1st