Ford Galaxy 6000RDS (in car audio system)?

First, it will show a radio station but no sound. Later it will come in intermittently on its own accord. Now it does not come on at all. When it comes on I can see the screen light up but at other times it freezes.
I 've pulled it out to check it's connections at the back just to see if there is a loose connection but to no avail. Somebody please help.