iMac 2010 21.5" - does not start up

[free.flyer]

I have an iMac 2010 A1311 EMC2389 which would not turn on, the fans did not run and there was no startup chime, it was completely dead.

I opened it up and checked the diagnostic LEDs and only LED1 was on.

I checked the lithium battery and it was at 2.8V, so I replaced it.

Now the iMac turns on, the fans run and the startup chime sounds, but only LED1 and LED2 turn on and the display screen is black.

I reset the SMC and tried to reset the PRAM but dont think that worked. Because I have a wired keyboard (PC) plugged into the USB port but there doesn't seem to be any power to the keyboard as the CAPS lock LED etc don't turn on (the keyboard works as I tested it on a PC). So if the keyboard has no power from the USB I assume it won't recognise the keys being pressed to reset the PRAM ?

There is no HDD fitted at the moment, I did try using a boot USB but it made no difference, which Iis not suprising if there is no power being supplied to the USB ports (as indicated by the wired keyboard)

I know LED 3 could mean its a video card fault, but I'm suprised that LED 4 is also off as this indicates and issue with the screen. Or is LED 4 off because there is an issue with the video card ?

I have the Apple Technician Guide for reference and aware it could be a faulty video card.

For the price of a video card I could get a complete working iMac (similar model) for the same price.

Therefore it seems pointless buying a replacement video card, especially if theres no guarantee thats what the issue is.

Is there anything else I can try other than replacing the video card or is there anyway I can confirm its definitely the video card ?

The fact there is no HDD fitted wouldn't cause any of these issues would they ?

 

[Bigwaff]

I have the Apple Technician Guide for reference and aware it could be a faulty video card.

First, get an Apple USB keyboard so you can activate boot key sequences. Second, if this were a generic PC circa 2010, how would you troubleshoot and diagnose the issue? I’m afraid you need to test the GPU card or swap in/out components.

 

[iCtheDUDEabides]

Its most likely the video card. You could do a bake on the one you have for free. Just, google how to bake a imac video card. Otherwise find a replacement on ebay or if you like, I can send you a AMD Radeon with 512mg that fits your iMac 2010 A1311 EMC2389.

 

[Nguyen Duc Hieu]

I have an iMac 2010 A1311 EMC2389 which would not turn on, the fans did not run and there was no startup chime, it was completely dead.

I opened it up and checked the diagnostic LEDs and only LED1 was on.

I checked the lithium battery and it was at 2.8V, so I replaced it.

Now the iMac turns on, the fans run and the startup chime sounds, but only LED1 and LED2 turn on and the display screen is black.

I reset the SMC and tried to reset the PRAM but dont think that worked. Because I have a wired keyboard (PC) plugged into the USB port but there doesn't seem to be any power to the keyboard as the CAPS lock LED etc don't turn on (the keyboard works as I tested it on a PC). So if the keyboard has no power from the USB I assume it won't recognise the keys being pressed to reset the PRAM ?

There is no HDD fitted at the moment, I did try using a boot USB but it made no difference, which Iis not suprising if there is no power being supplied to the USB ports (as indicated by the wired keyboard)

I know LED 3 could mean its a video card fault, but I'm suprised that LED 4 is also off as this indicates and issue with the screen. Or is LED 4 off because there is an issue with the video card ?

I have the Apple Technician Guide for reference and aware it could be a faulty video card.

For the price of a video card I could get a complete working iMac (similar model) for the same price.

Therefore it seems pointless buying a replacement video card, especially if theres no guarantee thats what the issue is.

Is there anything else I can try other than replacing the video card or is there anyway I can confirm its definitely the video card ?

The fact there is no HDD fitted wouldn't cause any of these issues would they ?

LED3 not turning on means failed GPU. You have read this part of the Apple Technician Guide, right?
To verify for the last time that the Video card is bad, you can remove it (and the LCD Panel) then boot it with a Linux USB.
If the iMac works fine (without the GPU and LCD), you can remote to the Linux operating iMac with SSH commands.
Another way (my way) to try is using a LED lit USB mouse. The LED light on the mouse will tell you something.

 

[free.flyer]

I have bought some artic silver MX6, is this suitablle for the GPU and the memory chips on the graphics card ?

I've seen people use two different types of thermal paste, one for the GPU and one for the memory chips, but I'm not sure why.

Some people mentioned that the paste was electrically conductive, but thermal paste is typically thermally conductive and electrically non-conductive (though some pastes might be slighly capacitve).

I've already removed the graphics card and baked in the oven at 200 degrees C for 10 min.

I just need to reassemble after putting the thermal paste on.

 

[free.flyer]

The baking worked ! The iMac is up and running again, just have to wait to see how long it lasts.

Thanks for all the help and advice