1
Score
drumheller
23
Asked
Video issues with diagnostic LEDs
About two weeks ago my Intel iMac (EMC2210) failed to boot. Upon pressing the power button I could hear the fans spin up, but the screen remained black and there was no startup chime.
So, I began looking for what might have happened. I hooked up an external monitor and got nothing. I searched here and ran across a description of the diagnostic LEDs. So, I checked the diagnostic LEDs.
#1 lights up when I plug in the power cord.
#2 lights up when I press the power button and stays on.
#3 lights up for a brief time when the power button is pressed and then goes out.
From the answers that I found on the diagnostic LEDs I figured that the video card had went bad. But this is where I am stumped. I ordered a brand new video card for the iMac and just finished installing it. Unfortunately, there is no change in the behavior of the computer. LEDs 1 and 2 still light and LED 3 still blinks and then goes out.
I am stumped. Could it be a bad power supply despite the #2 LED coming on? Could it be a bad mainboard? Is there any way to know if it is a bad mainboard? I don't want to sink any more money into the machine if it is toast. Any help or suggestions on what to check would be greatly appreciated.
Edited by: drumheller74 ( ) , mayer ( )
3
Score
mayer
150.7k
Answered
Accepted Answer
LED Startup Sequence
LED #1 = Power available.
If no LED is visible:
• Verify AC source
• Verify known-good AC cable is connected
• Verify cable connection between AC inlet and power supply
• Verify cable connection between power supply and logic board
• Verify power supply
LED #1 + LED #2 = Power available, and system is powered on.
If second LED is not visible when power button is pressed:
• Verify power button connection to logic board
• Verify power button functionality
• Verify cable connection between power supply and logic board
• Verify power supply
• Verify logic board
LED #1 + LED #2 + LED #3 = Power available, system is powered on, and video card found.
If third LED is not visible after power on:
• Verify that MXM video card is seated properly
• Verify logic board
LED #1 + LED #2 + LED #3 + LED #4 = Power available, system is powered on, video card found, and internal LCD found.
If fourth LED is not visible after power on:
• Verify cable connections between LCD panel and logic board
• Inspect LCD display cables for cable damage
• Verify external video functionality, and according to result check the following items:
-If external display works then verify/replace LED backlight board
-If external display works then verify/replace LCD panel
-If external display does not work verify/replace logic board
Was your video card supplier a reputable one?
Is it an iMac early 2008?
mistrato,
Yes, it is an early 2008 - MB324LL/A - iMac8,1 - A1224 - 2210 model. They really have a lot of ways to denote a machine.
drumheller74,