Ford/Visteon 4000RDS Radio Cassette?

I have just bought a used van fitted with the above unit and it does not work. It has power going to it(checked) and after taking it out have found that it has had scotchlocks tagged onto it to power a phone. The display gently glows green and clicks when powered up but alas doesnt even come up with a demand for a code to be entered.
Can this be fixed easily or is it a more complicated job? Can someone help please!!