Power Supply Board replacement - iMac is good as new!
The power supply of my mid 2011 iMac 27 failed
Watched the video guide and read this guide thoroughly, including all the comments, before starting the repair. It took me almost an hour, going slowly but surely. In the end the iMac powered up again and worked beautifully. Thank you guys for the guide and all the comments/feedback!
For this repair, as some had suggested here, I skipped steps 6 through 9 and only disconnected the vertical sync cable. Afterwards, I used two chopsticks (they are longer then pen) to prop up the LCD, using the holes of those T10 screws. Worked great, gave me two free hands and plenty of space to remove the power supply board (T10 screws, disconnect the two connectors), and put the new one in. To re-assemble, remove the two chopsticks propping up the LCD first, then carefully lower the LCD onto a big roll of packaging tape sitting on its side, placed near the camera, to hold the LCD panel open by about 2 inches, enough to reconnect the V-Sync cable with two free hands, lastly remove the roll and lower the LCD back to its place. That's it. The rest is easy. I figured the fewer connector touched, the better and it was a lot less stress. Those connectors are just so fragile.
Be very careful removing the glass panel using the suction cups. Once the panel lifted off of the frame, I immediately moved my hands to the side to grab the edge of the panel. Don't worry, there's about 1/2 inch of metal on the inside so no finger print will show up on screen if you grab the side. It is much safer that way to move the glass panel out of the way. Remove suction cups immediately or you may risk cracking the glass if you let it attached for a while. To put it back, just use hands to hold the glass on the side and slide it back in to the frame.
The magnet for the glass panel is very powerful. A couple of T10 screws I tried to remove got sucked over, but a small tweezer helped to remove them and put them back in.
Be sure to clean any dust off the LCD and glass panel no matter how small it may seem. I used a Swiffer dusting cloth, just brush it over the LCD and glass panel lightly, and all dust particles are gone quickly. The screen after boot up looked beautiful.