Справочник Пользователя для Apple MD094LL/A

iMac (27-inch, Mid 2010) Symptom Charts — Input/Output Devices 

 2010-09-09

1.  Verify if boot chime is present 

when system is powered 

ON. Make sure audio output 

preferences are not set to mute 

and volume is set to mid-range.

Yes

Go to step 2.

No

Reset PRAM and retest.

2.  Make sure no cables are 

connected to external sound 

input/output ports. Go to 

System Preferences > Sound > 

Output and verify that “Internal 

speakers” is an available option.

Yes

Go to step 3.

No

If “Headphones” is the only 

available sound output 

device, replace audio cable.

If “Digital output” is the 

only available sound output 

device, reseat audio cable to 

logic board. If issue persists, 

replace audio cable.

If issue persists, replace logic 

board.

3.  Go to System Preferences > 

Sound > Output. Set speaker 

balance 100% to LEFT speaker 

and play a known-good sound 

file. Verify if sound is generated 

by LEFT speaker and that sound 

quality is acceptable.

Yes

LEFT speaker and amplifier 

circuitry OK. Go to step 4.

No

No audio in LEFT speaker. 

Go to step 7.

4.  Set speaker balance 100% 

to RIGHT speaker and play a 

known-good sound file. Verify 

if sound is generated by RIGHT 

speaker and that sound quality 

is acceptable.

Yes

RIGHT speaker and amplifier 

circuitry OK. Set Balance slider 

to middle. Go to step 5.

No

No audio in RIGHT speaker. 

Go to step 7.

5.  Verify if user-reported audio 

issue has been resolved.

Yes

Issue no longer present. 

Return system to user.

No

Go to step 6.

6.  Boot system from Install 

DVD or another known-good 

bootable volume. Verify if issue 

still occurs.

Yes

Go to step 7.

No

Known-good boot volume 

works OK. Troubleshoot for 

software issue. Isolate if issue 

is application-specific or a 

possible OS conflict.