Chosen Solution

Hi all. We have a suspected power surge on a late model iMac. Logic board ID 820-3588 , power supply tested OK and swapped in known working power supply. Symptoms;

  1. No Trickle diag LED at all
  2. No power on , chime etc Blown Q7610 dual N channel mosfet which is a FDMS3602s FET http://www.mouser.com/ds/2/149/FDMS3602S… No other liquid or burn marks on board itself. Mosfet appears to have shorted or had voltage applied beyond its limits. Fet failed dramatically after a few power on attempts and was not blown initially on inspection. Have replaced part with exact match , no power on yet fet is intact thus far. Anyone else seen anything like this?

I had to extrapolate from your part number which machine you had. Please let me know if the icon is your machine. The first thing to do on this one is to replace the power supply: iMac Intel 21.5" EMC 2638 Power Supply Replacement