Rep: 11
1
1
I have this iMac, and it was working fine but now it does not turn on. I can hear the fan, but that is all.
I connected an external monitor, but this kept black too. I am not sure if it has a solution.
Is this a good question?
Rep: 479.3k
35
329
971
At this point its likely your power supply is gone. To be sure you’ll need to remove the display to look at the built-in diagnostics LED’s are telling you. Here’s how to remove the display iMac Intel 21.5" EMC 2389 Display Replacement. The LED’s are near the GPU frame.
LED #1
Indicates that the trickle voltage from the power supply has been detected by the main logic board. This LED will remain ON whenever the iMac is connected to a working AC power source. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power source is disconnected or the power supply is faulty.
LED #2
Indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.
LED #3
Indicates that the computer and the video card are communicating. This LED will be ON when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.
LED #4
Indicates that the computer and the LCD display panel are communicating. This LED will be ON when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.
Let us know what you see.
Well, thats good & bad!
The good is the power supply is AOK!
The bad … your GPU card is gone!
Here’s the IFIXIT guide you’ll need to follow iMac Intel 21.5" EMC 2389 GPU Card Replacement and here’s the needed info to get the needed part:
You may need to refresh the thermal paste and pads before you put the replacement board in.
Guide
Difficulty:
Moderate
Guide
Difficulty:
Difficult
—
50 minutes - 3 hours
Was this answer helpful?
Silly question, should connect an external monitor? Or I need to open the computer without disconnecting the screen?
No need for the screen.
So I disconnect the screen and see the LEDs, right?
Yes, fully remove it. Follow the guide I gave you. Do becareful with the ribbon cables as you can damage them if you tug on them.
I did what you said and I saw only the first two light going on. The 3 and 4 were off.
Past 24 Hours: 0
Past 7 Days: 0
Past 30 Days: 0
All Time: 123
5 Comments
What happens when you try putting your system into Target Disk Mode (boot you system and press the T key on you USB keyboard)? Do you see the FireWire icon on the screen?
by Dan
no. nothing.
by Albert
Do you get the POST tone when you press the power button?
by mayer
Aka the “bong” ^^
by [deleted]
No, the only I can hear is the fan.
by Albert