Audi A5 convertible Radio problem No sound

[eon]

Hi, just wondering if anyone can help regarding a sound problem on an Audi A5 2011 convertible
The radio is Harman Becker this is the unit in the boot had light water damaged but got it all dried turns on now did not before but!
There’s no sound, nor does the CD player work ie play a disk And cannot change the balance etc all turned down to 0 all grayed out, tcp in radio crossed out .
I got a replacement harman Becker the same model number etc but does the same as the original one the only different is the tcp in radio is on .not crossed out. I have not coded the replacement to the car is this why it does not work? I can take it to Audi dealer garage they said will cost £100 plus  to code the new unit, just don’t want to find out that it’s not the harman Becker unit and waste time and money.

Just wondering if you have any idea what the problem is and what I need to get it working
many thanks for any help.