[HELP] 2 Imac 820-2641 TOTALLY DEAD: NO LED/1 LED

[phantomEVO]

hi to all! please help with 2 imac 21,5 dead...

i already changed u7700 in both without luck

u7700 pin 17, 18, 5, 4, 24, 12

have those voltages in both imac..

12v, 5v, 5v, 5v, 0,3v, 3,9v

i have 3V3_S5 (L7710) in one imac (one led) but no 5v on L7750

NO SHORT ON L7750

i have not 3V3_S5 (L7710) in the other (no led)

PLEASE HELP I'M GOING CRAZY!!