I tried plugging in my apple headphone's jack into the socket, but I wasn't able to. Barely 70% of it goes in and the rest doesn't. There is no red-light coming out of the socket, but in the 'Sound' settings panel, the output device is 'Digital Out' -> 'Optical Digital Out Port'.
There is no sound emitted from the speakers and the sound icon in the taskbar is grayed out.
I managed to turn on/off the Analog to Digital switch inside the socket. The other (turn the switch 90ยบ clockwise) solution, I haven't tried yet. The weirdest thing is that there's nothing stuck inside the socket! I looked with a led flashlight, but for some reason, this jack won't go in.
Is this a hardware issue?! What are the next steps?
–Edit–
Adding the picture of the jack and socket and another for the 'Red Light of Death'.
Best Answer
When you insert the headphone into the socket, it makes connections internally against a number of poles which connect to the different rings on the jack end (left audio, right, mic, ground, data etc..). These are essentially tiny spring loaded contacts which the jack must push aside when inserting, that then rely on sprung pressure to maintain a permanent connection to the ring on the jack. Here are a couple of pictures, a diagram, and a photo or a replacement part that shows one of the poles:
These poles can jam, get stuck, fail etc etc. Usually a vigorous insertion is enough to free them, but this is relying on the chamfered edge of the jack to transfer vertical motion into a horizontal movement of the pole. You could use something slimmer than your jack, and insert (carefully, ensuring you don't insert it too far) before applying sideways pressure directly to the poles to try to get more energy into making them move.