2010 21.5 iMac failing to boot

[Hibyehello]

I just installed a new i7-870 and nvidia quadro K2100m into my imac, but after trying to start for the first time it fails to start, no chime or anything. I heard what I assume is the hard drive, but nothing else happens. Does anyone have any insight into what might be happening?

I will gladly provide more info if needed.

 

[Nguyen Duc Hieu]

I just installed a new i7-870 and nvidia quadro K2100m into my imac, but after trying to start for the first time it fails to start, no chime or anything. I heard what I assume is the hard drive, but nothing else happens. Does anyone have any insight into what might be happening?

I will gladly provide more info if needed.

There must be some errors in the assembling process that cause short circuit and prevent the iMac from booting.
To detect the issues, I would
detach the LCD panel, the HDD and the K2100, then power the iMac up to see whether it chimes and rotates its fans.

 

[Hibyehello]

when I took off the LCD I saw that the fans were rotating, no chime, but I do believe I muted the chime. I saw two LEDs turned on when looking at the motherboard, one seems to be just for power and the other turned on when I turned on the mac.

EDIT: I found what those LEDs mean and now I believe that something is up with the gpu

 

[Hibyehello]

I replaced the cpu with the original cpu and now my computer boots up. 2010 imac's are supposed to work with the i7-870 aren't they, because if so then my cpu must've been faulty

 

[Nguyen Duc Hieu]

I replaced the cpu with the original cpu and now my computer boots up. 2010 imac's are supposed to work with the i7-870 aren't they, because if so then my cpu must've been faulty

Perhaps not the core i7-870, but core i7-870s because of the PSU limitation.
Core i7-870 works well on my iMac 2010 27".

 

[RV-ABZ]

I concur, the 21.5" iMac11,x 2010 will only support the 82W "s" variant of the i7-8x0, i.e.:

• i7-860s
• i7-870s

The 95W i7-860 and i7-870 draw too much power for the PSU of the 21.5" models and can only be used in the 27" models.

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[applesaft]

Hello,
i have a iMac 11,2 (2010, 21.5). Earlier i have swapped my CPU to a 860s and was happy running High Sierra. But since Software support is getting bad, i thought about upgrading the GPU to a k2100m. I shoot one for about 50$ from china with the Elpida memory.
Now i have planted it into my system and i get only the first 3 LED shining up. I have flashed the GPU with the vBios of @nickey22 with the @xanderon usb stick method. The LCD screen stays dark after i boot up the system. On an external monitor i get an image. I have actually updated the OS to Big Sur already with OpenCore hoping this might change anything. I have done PRAM reset and holding the alt/option key.
To find the issue i have put in back the original AMD card. The LCD worked again. Now i wonder where i issue could be.
I would like to put the K2100m back in.