i have an 08 expediton xlt with the 6 disc changer that had some stuck discs so i took the radio out and removed the discs .... installed it back worked for a moment then poof nothing just a little pop and no lights. thought it was a power issue but its getting juice all fuses are intact and the heat sink gets real hot real fast.... i have no idea what happened. i have no other electrical issues windows cluster lights all work no issues just a hot radio with no power.

 

Internal short in the radio. I would unplug it and get another unit. They are cheap on ebay. Not worth fixing.