Chosen Solution

Hello There… I was wondering if someone can give some clue what is happening in this situation..: problem: iMac won’t turn on… tests:

  1. Removed lcd/glass panel successfully, I notice that NONE diagnostic led was on… so… I went..:
  2. I checked de AC cable, and it gave me the 120V AC from the outlet so we are good…
  3. checked inside AC input in the Mac, and also gave me the 120V AC… (good)
  4. I plugged in the PSU, and tested some pins with the ground pin… and 3 pins gave me 12V DC. (so I think the PSU is fine) What else can I try????

The PSU may receive power but is not sending further to the board, before going after a logic board damage i would try with a new power supply. Most of the cases when no diagnostic led is on the board doesn’t receive power due to a faulty power supply.