Somehow, headphones take priority over the digital output if both switches are on at the same time. Since the headphone jack still works with headphones plugged in, that rules out the audio codec and means it's a problem with the switch itself. You've correctly identified that the audio codec IC on the motherboard controls this selection, and although many users find that toothpicks or blowing really hard or a dab of isopropyl alcohol on a toothpick works for them, it's possible for the little switch inside the headphone jack to become nearly permanently stuck. I'm assuming you want to be able to use speakers and headphones as normal? It's unclear what you mean by 'Normal Digital audio out.' Optical digital audio out is the digital audio output if you're not using external USB/firewire/thunderbolt audio, so unless you're working with external audio interfaces switching between optical and digital does not apply as they refer to the same thing. I'll try my best to make the question more clear for every user. PS: This is not a duplicate and if you think so then please leave a comment below and I'll clarify it. Should I change the motherboard in order to hear the sound? Thank You! Now I can only hear the output from a headphone or via Airplay (Apple TV).

After some further research, I figured out that the switch between Optical and Digital is something which the IC in the motherboard controls. I tried the Toothpick method(Stick a nonconductor inside the audio jack) as said on the Apple Forum but no luck. Joseph's Solution worked a dozen times and never did again. One day, Just after a Normal Boot the Audio was not coming and the Audio was permanently muted but since I heard a lot about these issues on MCP from this era I did a small research on google and found these two websites, one from Apple and another from Joseph Hall's Blog. I have a Late 2011 MacBook Pro (2.2 GHz Intel Core i7) for six years which means no Apple Care or Warranty.

Imac digital audio output