Apple MD094LL/A Manuale Utente

iMac (27-inch, Mid 2010) Symptom Charts — Startup and Power 

 2010-09-09

3.  Wait 15 seconds after computer 

was powered down then 

disconnect AirPort cable from 

logic board. Verify if computer 

starts up properly now.

Yes

Go to 

 symptom flow.

No

Go to step 4.

4.  Startup with Alt key to select 

and start from the Install DVD 

inserted in the optical drive, 

or from an external bootable 

volume connected. Verify if 

computer starts up properly 

from alternate bootable 

volume.

Yes

Go to 

 symptom flow.

No

Go to step 5.

5.  Disconnect optical drive cable 

and retest. Verify if computer 

starts up properly now.

Yes

Reconnect optical drive and 

go to 

 symptom flow.

No

Go to step 6.

6.  Remove coin battery on back 

of logic board (you will need 

to completely remove logic 

board to do this), and leave out 

for approximately 1-2 minutes. 

Then reinstall battery. This 

will reset logic board. Verify if 

computer starts up properly 

now.

Yes

Issue resolved by logic board 

reset. Measure DC voltage on 

battery touching battery with 

red probe, and grounding 

with black probe. If voltage is 

2.7v or less, replace battery.

For multimeter help, see 

.

No

Replace logic board.