www.jec.org.uk

I have the Harmon Kardon factory fitted system with cd changer and amp in the boot etc. on an X-300 V12 The stereo sometimes decides it doesn't want to give output, the power stays on the actual unit itself, as if you had just turned the volume down, but the aerial retracts and no sound is heard. Sometimes you can turn the car off and it will all come back to life on re-start. I've checked all the conections as far as possible but can't seem to be able to remove the head unit for a more thorough examination. Any tips/clues?

Ah! The Jaguar/Alpine/Harmon Kardon sound system - a subject close to my heart. Here's how to remove the ski slope which then allows you to gain access to the head unit. http://www.skjagtech.co.uk/support-page ... radio.html
Apparently the HK sound system operates a strange active setup on the speakers, so you can't just plug in any other head unit. It will also cost £££s to have the system rewired. The Jaguar/Alpine head unit is tempramental....I have problems with mine (it doesn't switch to CD player), so much so that I bought a second-hand one, that didn't even power up, I sent it back and received another one which also didn't power up. I've either been ripped off or there is some other problem. I've dismantled my head unit as I'd been advised which component may be causing my problem, but still no joy. You are doing the right thing by getting the head unit out and looking for faults.
I live in central Scotland and if you live nearby I'd be willing to drive and try to sort out both cars stereos. Likewise, if there are any other JEC folks nearby who wouldn't mind me dismantling their ski-slopes and swapping head units/let me try a known working head unit, it would be much appreciated. A big ask I know, but if I don't ask.......
Hawks, let us know how you get on and I'll advise as best I can.
Good luck,
Lawrence.