Sound Settings: says speakers unavailable but headphones plugged in

[m654321]

Hi!

Just had the exact same problem on a laptop 2 days ago.
I'm addind to Trinidad's post because it was the headphone jack that was flaky.
I tried a few things but when I plugged in a pair of headphones in the jack to test if I had audio output there, I didn't even have to push it all the way in that the speakers began to work.
So, speakers are working now and I blocked the jack to be sure nothing else goes in there

Theory 1 - Previous owner maybe had a pair of headphones plugged in and connector was pulled/broken when the laptop was moved around.
Theory 2 - oxidation ?

Many thanks for this - backs up what TC said. If you look at the picture of the jack input, from outside the laptop (previous post), the socket doesn't seem to be centred (pushed to the left), so maybe physical damage ...