MacBook & The “Internal Speaker” Mystery

A couple of weeks ago I wanted to watch the “Don’t Give Up On Vista” video that appeared on the home page of the New York Times website. I could see the video on my MacBook, a 2GHz Intel Core 2 Duo running OS X v. 10.4.11, but could not hear the sound.

When I clicked on the Sound icon in the menu bar, the slider was grayed out. However when I plugged in external speakers I got sound. Now I was stumped.

First I looked in Sound Preferences. In the Output pane there was no evidence of Internal Speakers and all options were grayed out. But I knew my internal speakers were functioning because earlier I had heard the boot chime.

When I looked in the Input pane, it showed external speakers plugged into the Audio line-in port. I was able to move both the Balance and the Output sliders, check and uncheck the square next to Mute.

I unplugged the external speakers, trashed the com.apple.soundpref.plist in ~/Library/Preferences, logged out and logged back in to see if this would fix the problem. It didn’t.

Then I used an external firewire drive as the boot disk. The Sound Preference Output pane was still grayed out. No sound from the internal speakers.

After rebooting to my MacBook’s hard drive, I was going to call Apple with what I thought was a hardware problem, probably somewhere on the board. But I had some writing deadlines and did not feel like driving to the nearest Genius Bar and I was even more reluctant to ship my MacBook to Apple for repair.

Since I had spent most of the morning trying to fix my internal speakers, I decided to listen to the "Don‘t Give Up” video again. And in order to get sound, I’d have to plug in my external speakers.

This time it just so happened that the sun was behind some clouds so there was not very much light in the room. And I had to bend down close to the left side of the MacBook to plug in the speaker cable. As I did so, I peered into the port and could see a red light shining inside. That's funny. I didn’t remember seeing a red light there before: wonder what it means. Must be on the logic board close to the Line-In port, I thought. So what to do? — I’m not going to spend time taking this thing apart — I used a bent paper clip and stuck it inside the port to poke around a bit, for what reason I do not know. (Be polite and call me curious.) And I figured I had a hardware problem anyway, what more harm could I do? (Lots. Like void the warranty. . . .)

After a couple of gentle jabs producing lots of static (I don’t recommend you’re doing this by the way), the red light went out. Then I heard PC talking. I moused up to the sound icon and this time I was able to move the slider bar up to increase the sound.

Later I read that the internal speaker malfunction is caused by a faulty I/O board. Apple will replace it since my MacBook is still covered by AppleCare. But I think I’ll wait for a while to see if it happens again.

Oh. And if you’d like to see the “Don’t Give Up on Vista” video, click here.