Ford 6000cd problem

Hi there, I have a ford 6000cd fitted to my explorer which developed a fault
where u could turn it on and off and listen to one station ok, but none of
the radios controls(push buttons) functioned, meaning that you couldnt tune
it or alter the base and treble ect..
I took it out to look for anything obvious but now I've reconnected it the
buttons still dont work so i cant input the code!
Any ideas (apart from buy a new one) mucho appreciated.


Cheers

Marto