I have a MacBook Air A1237. I can hear the "dong" from startup, but in OS I couldn't hear anything.
In System Preferences, as output, I see only headphones. If I plug in a headphone I can hear sounds, music. If I plug out this, nothing happend. The internal speakers are not showed. I've tried to reset NVRAM and SMC, install a new copy of OS, same problems. I tried to clean with a toothpick, nothing happened. Any other idea to solve the problem?