Hissing/crackling coming from left speaker of MacBook Pro

I realize there are some posts about similar issues, but unfortunately none of them have helped me.

I have a first-generation intel MacBook Pro, and until now the only issue I've had with it is a toasted hard drive (which I could fix myself without any trouble). Unfortunately, a couple of days ago a new issue began.

Say the computer has been sleeping or powered off for an extended period of time (this period is shorter than eight hours, but longer than one). Then I wake it up/turn it on, and it's fine. Then any sound plays (received a new email, changed the volume, etc.), and suddenly the left speaker is hissing and crackling. Neither changing the volume nor muting the speakers changes this. Indeed, the only way to stop the hissing is to plug headphones in (the headphones do not hiss or crackle), or put the thing to sleep/turn it off again.

This sound is annoying enough that I can no longer listen to music or watch videos while using the built-in speakers. I have found a couple of posts on a couple different forums (this one included) where OPs had similar issues. Unfortunately for me, in each case the OP's laptop was still under warranty and just got it fixed. Mine, on the other hand, is several years out of warranty.

I am a recently-graduated Computer Engineer. If I know what's wrong and can order the parts, I feel relatively comfortable fixing this myself. My problem is that I have no idea what's wrong! In one of the posts I mentioned, the solution was to replace the logic board. Could this be my issue as well?

If I can figure out what's wrong (hopefully someone here can help me on that), does anyone have a recommendation for where to buy replacement parts for a generation that is this old?

I'd appreciate any help.

Replacing the logic board would be the very last thing to do as that is the most expensive and also very difficult.

I suggest replacing the speaker itself at first. Since the hissing crackling sound is not coming from your headphones, that would indicate the sound system is OK. There may indeed be something else at fault, but the easiest is to swap the speaker. If that doesn't cure it, you can go from there.

Go to iFixit: The free repair manual and find the speaker part for your MBP and while you're there, look up their take apart instructions for your model. Let us know how it went.

Regards.

Thank you, chscag; I'll give that a shot and post back.

It's interesting: The speaker plays fine while it's hissing and crackling, and I can localize the hissing and crackling as coming from the top center of the speaker area (the punched-out aluminum). If fact, it's so localized that if I put my finger there, I effectively silence the noise (while still being able to hear the music). I do hope it's the speaker!

Thanks again for your help.

Well I got the speaker in the mail today and put it in... and the sound didn't go away. What's the next step?

Well, replacing the speaker was a good shot - easier than trouble shooting the logic board. Too bad it didn't work out.

I just did a search of the Apple forums and found numerous problems similar to yours with MB and MBP speakers. The vast majority turned out to be a defective speaker.

I'm finding it hard to understand why the headphone output is OK but the speaker is not. That would seem to tell us that the sound system is OK. Unless there is something else involved, I would hate to say it's the logic board. A logic board swap is expensive and not easy to accomplish. If it comes down to that, I recommend living with the problem or when at home use external speakers instead.

If I come up with another idea. I'll post to this thread. I'll do a bit more searching to see what I can find.

Regards.