iMac 24'' 2011 doesnt chime

[eoegbero]

I got a 24 inch imac 2011 that when powered on, the fan runs but the system does not chime and the screen stay black. I look at the diagnostic LED and only the first one comes on, while the other three is off.
Please, I need help. Thanks

 

[Fishrrman]

Bad GPU?

What happens if you try a "safe boot"?
To do that, press the power-on button and IMMEDIATELY hold down the shift key and keep holding it down a while...

 

[eoegbero]

I tried the "safe boot" but the screen remains black. Even if the GPU is bad, the screen should brighten up showing a circular symbol and chime when powered up. Picture of motherboard shows the diagnostic LED atached.

 

[Nguyen Duc Hieu]

I tried the "safe boot" but the screen remains black. Even if the GPU is bad, the screen should brighten up showing a circular symbol and chime when powered up. Picture of motherboard shows the diagnostic LED atached.

Try one more test
- Remove the MXM card from its slot.
- Power-up the iMac again (with no GPU)
If you can see 2 LEDs lighting, then only the GPU is bad. The iMac might chim, the OS might still boot and you can see your iMac IP address on your router homepage.

If you still see only 1 LED lighting, then the logicboard is bad, too.

 

[eoegbero]

Try one more test
- Remove the MXM card from its slot.
- Power-up the iMac again (with no GPU)
If you can see 2 LEDs lighting, then only the GPU is bad. The iMac might chim, the OS might still boot and you can see your iMac IP address on your router homepage.

If you still see only 1 LED lighting, then the logicboard is bad, too.

Hi, I removed the MXM card and two LED came on. Connect the screen and power on, the iMac chime but the screen remain blank.
The disk is formated, could that be the reason why the screen is black?.

 

[Nguyen Duc Hieu]

Hi, I removed the MXM card and two LED came on. Connect the screen and power on, the iMac chime but the screen remain blank.
The disk is formated, could that be the reason why the screen is black?.

The screen is black because the MXM card (GPU) was removed. Other parts of the iMac are still working fine.
When the GPU was in place, it caused a short to your logicboard => only 1 LED (PSU is working)

Now you have a choice to either install another working GPU or throw/give/sell away your iMac.