Sony XR C7200R - no restart code and new car batt needed!!!

[Col]

Hi. I'm hoping someone can help......

I've just bought a 2nd hand car with one of these Sony units fitted. None of the documentation/manuals has a clue to what the code for the head is and guess what????? - I need to replace the battery in the car!

Managing to keep it going with standard auto battery charger but can't carry on this way. It gets embarrasing when I can't restart the car in the local carparks!!

Anyone out there got an operating manual for one of these? Just to know how to access the code so I can enter a new one would be great.

C