iMac (27-inch, Mid 2010) Symptom Charts — Input/Output Devices 97
2010-09-09
5. Inspect microphone cable
routing and verify if cable is
pinched or damaged.
Yes Replace rear housing
(microphone cable not
available separately).
L14
No Go to step 6.
6. Record sound sample using
GarageBand or iMovie. Verify if
sound quality of sound sample
is normal during playback.
Yes Microphone circuitry OK.
Return system to user.
No Replace logic board. M09
Audio: Built-in Speakers Have Distorted Sound
Unlikely cause: LCD display, power supply, hard drive, optical drive, fans
Quick Check
Symptoms Quick Check
Audio: Built-in Speakers Have
Distorted Sound
• No audio from one or both
speakers.
• Audio from speakers distorted
1. Go to System Preferences > Sound > Output.
Verify that sound output device is set to internal
speakers and that balance control is set to the
center position.
2. Obtain known-good high-quality sound le or
use iTunes Store sound samples to evaluate
sound quality. Verify suspect sound les on
another system to determine if distortion is
caused by computer or sound le.
3. Set volume control to mid-range. Overdriving
built-in speakers can cause distortion.
Deep Dive
Check Result Action Code
1. Go to System Preferences >
Sound > Output. Set speaker
balance 100% to LEFT speaker
and play a known-good sound
le. Verify if sound is generated
by LEFT speaker and that sound
quality is acceptable.
Yes LEFT speaker and amplier
circuitry OK. Go to step 2.
No Distortion detected in LEFT
speaker. Set Balance slider to
middle position. Go to step 3.
2. Set speaker balance 100%
to RIGHT speaker and play a
known-good sound le. Verify
if sound is generated by RIGHT
speaker and that sound quality
is acceptable.
Yes RIGHT speaker and amplier
circuitry OK. Set Balance slider
to middle. Go to step 3.
No Distortion detected in RIGHT
speaker. Go to step 4.