Is there some sort of operation that has to be performed on the radio if the car battery has been disconnected for some time?

I have no display on my radio (1997 XJ6) and when I click the on/off switch nothing seems to happen.

Is it best just to bite the bullet and replace it with a modern CD & MP3 capable head unit?

 

I believe you can contact any Jaguar Dealer and they'll lookup the security code for you from the VIN

 

It is general consensus that US cars did not have a radio security code, but there have been reports that some have observed a few exceptions to that rule. But it should just power on without anything special.

If yours isn't even turning on, I don't think it is a security code issue, as the radio would need to power up first and ask for the code.

I'd suspect an issue with power to the radio such as a fuse, or the radio itself. The OEM Alpine radios are well known to develop problems powering on. Mine eventually got to a point where it would power on only after many attempts, usually after pressing the tape eject button first also many times.... eventually I had it rebuilt.


Some relevant threads on X300 radio codes:

https://www.jaguarforums.com/forum/x...please-174243/

https://www.jaguarforums.com/forum/x...o-code-128770/

https://www.jaguarforums.com/forum/x...e-x300-102973/

https://www.jaguarforums.com/forum/x...an-done-86892/


And here's the major thread on radios not powering on:

https://www.jaguarforums.com/forum/x...nt-turn-54075/


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As Al said....Probably your radio head acting like its kind. They take spells where the buttons are only decorative..and if you've left it on..it's on when the key is on. If off, then off.....all the time. Part of the character of the brand, I guess.