4. Pivot enclosure to access

Yes

Logic board communicating

 

lower intake vent, and locate

 

with video card. Go to step 5.

 

diagnostic LEDs on edge of

 

 

 

No

If LED #3 does not turn ON

 

logic board. Verify if LED #3

 

 

reseat video card and retest,

 

turns on shortly after system

 

M03

 

then replace video card and

powers on.

 

 

repeat step 4. If issue persists,

 

 

 

M03

 

 

replace logic board.

 

 

 

 

 

 

 

5. Locate diagnostic LEDs on

Yes

Logic board communicating

 

logic board. Verify if LED #4

 

with LCD panel. Go to

 

turns on shortly after system

 

Backlight Issue/No Backlight

 

powers on.

 

symptom flow.

 

 

 

 

 

 

No

Replace DisplayPort cable. Go

X03

 

 

to step 6.

 

 

 

 

 

6. Locate diagnostic LEDs on

Yes

Video controller functional

 

the logic board. Verify if LED #4

 

and communicating with LCD

 

turns on shortly after system

 

panel. Go to Backlight Issue/

 

powers on.

 

No Backlight symptom flow.

 

 

 

 

 

 

No

Video controller unable to

 

 

 

communicate with LCD panel.

L03

 

 

Reseat cables first. If issue

 

 

persists, replace LCD panel.

 

 

 

Retest.

 

 

 

 

 

2010-09-09

iMac (27-inch, Mid 2010) Symptom Charts — Startup and Power  47

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Image 47
Apple MD094LL/A manual Diagnostic LEDs on edge, M03, Locate diagnostic LEDs on, L03