Chosen Solution
MacBook Pro 13" 2009 A1278 I have a sound problem in where it doesn’t output sound, the sound displays crossed out. The original problem was the speakers had a crackle sound , I then replaced the speakers L/R. When I restart the the MBP, I do hear the Apple chime once but the sound appears to remain disabled. Anything that i should be looking for? Update (10/20/2021) Dan, thank you for your prompt response. Regarding the headphone jacks, I barely use them but none the less I have checked them and they seem to be in order. Somehow I still have the same problem in where the sound symbol appears when I press sound up/down but below it also displays “ø”. Note that the Apple chime sounds when I restart the computer. Your help is appreciated.
I bet you use your headphone jack a bit. What happens is the jack has a set of switches which normally send the audio signal to the speakers and when you insert the headphone plug the connection is to the plug as you can see here
So you’ll need to see if the switch blades have shifted so they are not touching or there is some dirt interfering with them.
@gonziva since you just replaced the speakers due to the crackling, double check your work and the connectors etc. I would also suggest that you at least give the Apple flowchart a try and see if that yields anything. Otherwise I believe that your decision is the right answer.
