Hello everyone, I own and love a MacBook Pro 15" A1211 but I've been dealing with this red optical light and no sound from the speakers issue a little too long. I've literally tried everything to no avail! I'm left with no choice but to start replacing parts bc having such a wonderful notebook sucks when you can't use all of it's goodies. So I know that I have a problem with the actual headphone jack itself because I did manage to "fix" the issue temporarily using a Q-tip and heard my speakers loud and clear! The issue came back shortly and I was depressed again haha. My last resort?: replacing the left I/O board. The part is fairly expensive but worth it to me and I know I can do the instal myself. A Question: this WILL solve my problem since replacing it with a new I/O board (not used) because no headphone jack has been raping the jack correct?? I can definitely live without using headphones to be honest but it's so annoying not being able to hear anything out of my internal speakers!