Sound problems Dell E6410 lubuntu / ubuntu

I am having problems with sound in internal speakers (have no headset to check if the output is going well).

I had Ubuntu 16.04 and from the beginning there was a problem - after reboot I had to manually change the output device to get the sound. It worked pretty good for almost half a year but one night I was trying to access arduino - this night has changed my life.

I have broken the sound on internal speakers playing with sound configurations. Arduino problems made me reinstall the system to get Lubuntu 16.04 - with the same problems in sound but I have not resolved them yet.

I have upgraded the system, alsa, linux-audio..... pulseaudio...

Alsamixer, pavucontrol (this worked before but not this time)

http://www.alsa-project.org/db/?f=de2d58fc4ff228c9ce43777e5342daa6fb1f1f4d

I have no idea what the hell I have done here.

Please help me guys - I don't want to use windows any more.