Symptom Charts

Follow steps in the order indicated below. If an action resolves the issue, retest system to verify.

Startup and Power

No Power, Dead Unit

Unlikely cause: speakers

Quick Check

Symptoms

Quick Check

 

 

 

No Power, Dead Unit

1.

Verify power source.

No power

2.

Verify power cable.

No fan spin

3.

Listen closely for signs of activity from system

No startup chime

 

including: rotating fans, hard drive or optical drive

• No image on external display

 

 

activity, startup chime, etc.

 

 

 

No hard drive or optical drive activity

Caps Lock LED on wired keyboard doesn’t light when pressed.

Deep Dive

Check

Result

Action

Code

 

 

 

 

 

1.

Power ON system. Verify if

Yes

The symptom is powering

 

 

there is any indication that the

 

up. Go to Won’t Start Up

 

 

system has powered up (fan

 

symptom flow.

 

 

rotation, hard drive or optical

 

 

 

 

 

 

 

 

drive noise, backlight turns on).

No

Go to step 2.

 

 

 

 

 

 

2.

Locate the diagnostic LEDs

Yes

Standby power voltage being

 

 

in bottom case vents. Plug

 

supplied by power supply.

 

 

AC cord into system. Verify if

 

Go to step 3.

 

 

diagnostic LED #1 turns ON.

 

 

 

 

 

 

 

 

You may alternately check for

No

Go to step 4

 

 

presence of a 12V DC signal

 

 

 

 

between pin 4 and pin 1 of the

 

 

 

 

logic board.

 

 

 

 

 

 

 

 

2010-09-09

iMac (27-inch, Mid 2010) Symptom Charts — Startup and Power  35

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Apple MD094LL/A manual Symptom Charts, Symptoms Quick Check No Power, Dead Unit, Check Result Action Code