Inspiron 16 5640, no audio jack output

About 3 days after receiving my Inspiron 16 laptop I realised that my 'universal audio jack' was no longer working.  It had worked initially but then stopped. When plugging in headphones the speakers were not isolated and there was nothing through the headphones. I tried 4 different headphones with no success, and the normal trouble shooting.  When I had no success I got onto support.  They talked me through a number of procedures then tried a remote logon and tried some more options themselves. It dragged on for nearly a week (another story by itself) and then they agreed to replace the motherboard.  A tech turned up with a 'daughter board' a small printed circuit board that incorprated the audio jack. That didn't fix the problem. The tech then replaced the mother board and it fixed the problem to an acceptable level. That is you could not plug in the headphones while there was audio playing and have the system change from speaker to headphone, but if you plugged in the headphones then started a playback it seemed to work.  Well it did work until a couple of hours after the tech left when I tried to use the headphones ... and again no output through the phones.  

I bought two laptops together, one for me and one for my wife. My wife wasn't having any problems and she checked my settings against hers and found that in System-Sound-All sound devices-Properties, under 'Licence Status' she had Dolby Atmos for Speakers & Dolby Atmos for Headphones while I only had Dolby Atmos for Speakers.

Has anybody got some suggestions they can offer?  Thanks

ps. EVERY driver has been loaded and all updates have been entered.