Chosen Solution

iMac Intel 27" EMC 2429 2.7GHz Hi, I have iMac27" with some problem on power supply unit. The noise is terrible and unacceptable. I open iMac and at the moment I have to try PSU stand alone to understand if is PSU problem or other boards connected to it. Imac run correctly, power is correct but the noise is very terrible. PSU is LITEON pn 614-0446 PA-2311-02A REV:B. I need:

  1. schematic pin out 16 pin connector
  2. similar experiences in the world: it’s very terrible to discover this terrible noise. Thanks

I would recommend just replacing the PSU not trying to fix your current unit. Often when I get these squealers I end up replacing quite a few parts and end up wasting a lot of time. The transformers and the filtering capacitors often need replacing. Unless you don’t have the fixtures and proper tools to work on the it can be dangerous!