Audio not working on macbook pro

Question

Hi,
I have a 2007 Macbook pro. I have changed battery for this laptop twice in the past 5 years. As everyone else, I experience overheating issues. Otherwise, it has been working fine.
Today, I started using the itunes store to browse tv shows, books, and music. Suddenly I heard a big rattling noise (really loud) in my mac and it was coming from the top left side (probably the fan!). I quit the applications and shut down my laptop. When I restarted the mac, I could not listen to any songs neither from my mac nor from the internet, say youtube. No audio of any sort is working in my mac right now, not even the alert sounds.
- I checked the system preferences and could not change any output controls.
- After sometime, Ive also started noticing the red light in the headphone jack. But, this red light comes on intermittently. I tried putting my headphones in and out 3-5 times, it still did not solve the issue. The light may go off, but there is still no audio from my mac.
- Everytime I restart my mac, I hear the rattling sound. I checked my hardware, repaired the disk (using the Mac OSX disk), reset SMC, PRMV settings. None of these helped.
Im worried that my fan has gone bad and this in turn has also affected my internal audio system for some reason? I would appreciate any troubleshooting tips in this regard!
Thank you!

Answer 1

Well, for the red light issue, cut the end off a Q tip, or clean cut a Wooden tootooth pick(NO PAPAER CLIPS OR ANY OTHER CONDUCTIVE MATERIAL) and GENTLY "massage the headphone jack,(there is a micro switch that can hang, stop at the LEAST amount of resistance). Reboot see if that helps.
Also go to system preferences>sound>output tab and make sure the mute box is not checked, set the volume slider is at least half way up, and make sure built in speakers are selected.
If this does not solve your issue, go to utilities>Audio/MIDI set up, click putput tab, and make sure source is set to  built in speakers, when selected double click on the built in speakers log out and reboot.
If you have been using Garageband, launch GB and go to GB preferences>Audio/MIDI, and select from the output tab intrenal speakers.
Here's what worked for me. It's not a workaround, this acutally solved the problem and I haven't had speaker issues since.
Go to "Activity Monitor" (you can hold "Command" "Shift" and press "U" if you're on the desktop).
Locate "coreaudiod" under "All Processes"
Right click it and click on "Quit"
After several seconds, "coreaudiod" will restart on it's own and your speakers will return to normal.
I tested this by restarting to see if it was a fluke workaround. Then I turned it off and waited a day (I had things to do so the waiting a day was easy lol). Turned it on, it was fine. I put it on sleep mode, waited 10 mins. and took it off of sleep mode. It was fine. Everything went back to normal for me.
Rattling sound is a concern for me as ths not normal, I would back up eveything, as this could br a HDD on the way out, and you want to save your data.
Also, you can try a a Pram reset:
If you have a removable battery, power doen your MBP, disconnected the power adapter, remone the battery, hold the power button down for 10 seconds, reinstall battery and mag safe and booy up.
If you have a MBP that has a non removable battery, follow the folling instructios.
Power off MBP, power it back on, holding the following keys: option, command,P,R, (no commas), press these key immediatly before the start up chime ringd, continue you to hold therse keys till you hear the start up chime ring ring 2 timess amd release.
Reboot
Since you had the battery replaced, you might want to try an SMC reset if non of the above offers any help. Power down MBP, power back up, hold the following keys before the star up chime. Left key shift,control, option, contine to hold these keys till the gear stops spinning.
Rebot.
All the best, I hoe this helps.
Let me know if this worked for you