User Guide

iMac (27-inch, Late 2009) Symptom Charts — Startup and Power 38
2009-12-16
No Video
Unlikely cause: hard drive, optical drive, speakers, camera, microphone
Quick Check
Symptoms Quick Check
No Video
No image.•
Backlight failure.•
Check brightness setting.1.
For no-video issues, connect an external display 2.
to Verify if iMac video circuitry is functioning.
If image appears on external display go to
Backlight Issue/No Backlight symptom ow.
Reset SMC.3.
Deep Dive
Check Result Action Code
Verify boot chime present and 1.
fans running when system
powered ON. (Reset SMC and
clear PRAM if necessary for
proper boot up.)
Yes Power ON self test OK. Boot
sequence started.
Go to step 2.
No Go to Won’t Start Up
symptom ow.
Verify if image is visible on 2.
built-in LCD panel.
Yes Video present. Verify system
functionality and return to
user or jump to appropriate
troubleshooting ow.
No Go to step 3.
Connect supported external 3.
display. Verify if image appears
on external display when
system is booted.
Yes External display detected by
system. Video circuitry on
logic board functional.
Inspect DisplayPort cable to
back of panel connection.
Reseat and test again. If you
continue to have problems
go to Backlight Issue/No
Backlight symptom ow.
No Go to step 4.