Skeptical at first; delighted in the end.
After the audio on my MBA original cut out, I assumed from what I was reading online that a logic board replacement with its concomitant expense was in my future. After poking around the net, I stumbled upon iFixit and read that replacing the audio cable often cured the problem. I'm reasonably handy and it seemed like a low-cost way to achieve the repair. I was also wary that replacing the logic board was the right way to go since I could still play music on a Bluetooth speaker from my MBA which made me think that the sound circuitry was actually still intact.
Fortunately, I had recently purchased a new MBA 11" for my wife so I could follow iFixit's excellent repair manual side-by-side as I worked on my older unit. The replacement of the audio cable was a snap. As others have observed, it only took me about a 1/2 an hour to complete. Many of the steps involved are only necessary because so many internal components lie over or near the audio cable.
When my MBA first rebooted, I got nothing - no sound. I thought "there's a waste of 30 bucks". For some reason, I decided to reboot a second time and then...voila! The sound was back and has remained on ever since. I couldn't be more relieved. I think I'm only going to hold onto this MBA for a few more months or maybe a year, but at least I'll have my internal speakers working again.