No audio, nor headphones nor internal speakers. It's not that its stuck on digital mode. No chime on startup. It is not locked or anything, though occasionally grey and comes back to normal, but still never any sound. I followed online instructions: I checked the sound settings, inserted an Apple headphone jack several times in all sorts of recommended combinations, quit coreaudioid in Activity Monitor and in Terminal, reset PRAM/NVRAM, and SMC.I also tried to delete the Audio folder in Library Preferences as someone had suggested, but its locked. So no luck... I noticed this problem yesterday, but it may have occurred earlier... Nevertheless, yesterday morning when I turned on my computer the date was changed to Dec 31st 2014 at 10:00 pm (I'm not sure if this is related to the Audio problem). Another issue, but this one has been present from very early on, is that the jack gets VERY hot when charging the computer when it's turned on (again, not sure if it's related or not, or if it's even normal, since it has been that way from the beginning). The MagSafe isn't damaged at all. The computer is less than 2 years old and I got it after my earlier MacBook Pro had a motherboard problem before it was a year old. I live in Easter Island which means the nearest Apple place I can take it to is 3,900 kms away. The computer is running on Yosemite 10.10.5; I haven't been able to upgrade to El Capitan because the Internet on the island is very slow and the download keeps getting interrupted. I hope someone in this forum can help me, and I very much hope it's not a motherboard problem, again. I have a MBP 15" late 2015.