Chosen Solution
I just won an iMac 21.5” Mid-2011 desktop computer from eBay. Upon receiving it, I hooked it up, heard the chime sound at booting, but got a black screen. Have tried many different tips found on internet, including press and hold power button for 30 secs, reset PRAM, remove all RAMs then put them back, hold down Option/Shift/Command-R, and so on, to no help. Screen is completely black still. Any suggestions to resolve this issue of my iMac are greatly appreciated.
Sadly the GPU board has failed! So now you’ll need to decide to return it to get your money back (what I would do) Or replace it if you can find the needed part (getting hard to find) iMac Intel 21.5" EMC 2428 GPU Card Replacement
