Apple 2009 iMac - Page 38

iMac (21.5-inch, Late 2009) Symptom Charts — Startup and Power 38
2010-11-18
4. Pivot enclosure to access
lower intake vent, and locate
diagnostic LEDs on edge of
logic board. Verify if LED #3
turns on shortly after system
powers on.
Yes Logic board communicating
with video card. Go to step 5.
No If LED #3 does not turn ON
-If system has a separate
video card, reseat video card
and retest, then replace video
card and repeat step 4. If issue
persists, replace logic board.
-For a system without video
card, replace logic board.
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5. Locate diagnostic LEDs on
logic board. Verify if LED #4
turns on shortly after system
powers on.
Yes Logic board communicating
with LCD panel. Go to
Backlight Issue/No Backlight
symptom ow.
No Replace LVDS cable.
Go to step 6.
6. Locate diagnostic LEDs on
the logic board. Verify if LED #4
turns on shortly after system
powers on.
Yes Video controller functional
and communicating with LCD
panel. Go to Backlight Issue/
No Backlight symptom ow.
No Video controller unable to
communicate with LCD panel.
Reseat cables rst. If issue
persists, replace LCD panel.
Retest.
M03