Apple MD094LL/A Manuel D’Utilisation

iMac (27-inch, Mid 2010) Symptom Charts — Communications 

 2010-09-09

Unlikely cause:  LCD display, power supply, hard drive, optical drive, fans

Ethernet Port/Device Issue
•  No Ethernet device present
•  Unable to access network 

resources

•  Ethernet device shows no 

connection

•  Ethernet device unable to an IP 

address

•  Slow network performance

1.  Check Ethernet cable for damage. Try a 

known good Ethernet cable – CAT5 or better 

recommended for 100Mbps+ connections.

2.  Check Ethernet ports on the computer and wall/

switch for dust, debris, damage or bent pins.

3.  Ensure distance from networking infrastructure is 

less than 300 feet/ 105 meters.

4.  Verify port, cable and network hardware with a 

known good system. Isolate firewall, MAC address 

filtering or hardware access control devices.

5.  Isolate OS by starting up from original Install 

media for this computer, a same-model computer 

in Target Disk Mode, or compatible known-good 

OS on an external drive.

1.  Visually inspect Ethernet port 

of computer and ensure that all 

pins will make physical contact 

with the Ethernet cable.

Yes

Go to step 2.

No

Pins are damaged, bent flat or 

missing. Replace logic board.

2.  Boot from original Install media. 

Verify Network Link status is 

active by using Network Utility 

under the “Info” tab. Verify if the 

Link Status is “Active”.

Yes

Go to step 3.

No

If same Ethernet cable gives 

an “Active” link status on a 

known-good, same-model 

computer, replace logic board.

3.  Connect computer to another 

Mac using CAT5 Ethernet 

cable. See article 

. Verify if you connect 

successfully.

Yes

Ethernet communication 

good. Go to step 4.

No

If same Ethernet cable and 

computer connects to a 

known-good, same-model 

computer, replace logic board.