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Getting Sound Back on a Macbook Pro (when the headphone is stuck on Optical)

Forrest Christian Computers/IT 2 Comments

A regular problem for me with my Macbook Pro is getting the sound disappearing because the headphone jack gets stuck in optical mode (TOSLINK on). You can tell it’s happened because:

  1. a red light is on inside the headphone jack (the light is the TOSLINK signal); and
  2. adjusting the volume through the sound controls brings up a sound meter with a “no signal” symbol below it (looks like a do not enter sign).

What happens

The headphone jack on the Apple Macbook Pro serves two output channels: a normal audio out and TOSLINK out. Inside the jack is a very small switch that turns on and off the optical audio output while simultaneously disabling the internal speakers. The switch can be turned on by simply using headphones. Almost any 3.5mm TRS audio plug can cause the problem, although some are worse actors than others. The design of the component that Apple uses is known to be poor but Apple doesn’t have to fix technical problems because it’s a design company and bad engineering never hurts them.

The Solution

Setting aside the fact that making it do double duty is stupid design, here’s how to fix it.

  1. Get a toothpick. You can use an unfolded paperclip but wood is less likely to damage the innards.
  2. Look inside the 3.5mm TRS/TOSLINK jack for the little switch. The TOSLINK signal acts like a nice flashlight.
  3. Find the switch in the back at about 12 o’clock, looking straight in with the laptop sat flat on a surface. At least it was at the top of the TRS tube in mine.
  4. Gently probe the switch with the toothpick and try to get it to turn off. You will know that you’ve been successful when the TOSLINK red light turns off.

That’s it. It drives me nuts on a regular basis and each time I have to paw through endless unhelpful complaints in Apple forums to find the answer. I figured I would put it up here and make it easier to find for everyone.

QUICK NOTE: I hope this was useful. I provide career consulting to smart people stuck in their careers, and business strategy consulting to businesses who have to change or die. Check out the other posts for some great info on how to better manage your career and your company!

“Bessemer converter (iron into steel) Allegheny Ludlum Steel e Corp Brackenridge, Pa (LOC)” [crop]. Ca. 1940. Alfred T. Palmer via Library of Congress

Comments 2

  1. Pingback: Apple:MBP Headphone Jack Doesn't Work in OS X but does in Windows – Apple Questions

  2. Thank you! You helped me fix my sound problem! There wasn’t a red light on continuously for me but all the other issues were present: No sound on my speakers all of a sudden but I could get audio through headphones. I had just happened to look at my computer for a moment to notice the red light, that turned on for a few seconds. If I hadn’t looked at that moment, I wouldn’t have even known that was a related issue. I unfolded a bobby pin (that has a protected tip) and pushed the very end on the inside of the jack a few times. I could hear a slight clicking sound and then tada! My speakers are working fine now. 🙂 Thanks for guiding me to fix it!

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