Chosen Solution
I have Mac OS X 10.7.5 (Year-old Desktop). The sound tells me that it’s all the way up, but it shows a ø sign under the sound volume. it will not let me adjust the sound, and it does not play sound. When l restart the computer, instead of the normal Mac startup sound, l get this loud tapping noise for a few seconds. Safebooting doesn’t help, restarting doesn’t help. Plugging cables in/out of the sound output and input jacks doesn’t help. Could the audio board have gone bad as suggested here? What can l do about it?
As your system is still on the newer side I would bring it in to an Apple Store for them to check out. Bring in your sales receipt to prove the exact date you bought the system (hold this as your Ace up the sleeve if you encounter push back on warranty coverage based on the manufacture date). I suspect you have a logic board issue here in the DAC.
The audio board may have issues, but it could be a driver issue. Try reinstalling Mac OS X.
