supamodz
Member
Working on a 820-2850, customer stated i was doing a party and mac dies in the middle of the session. When i opened the back cover and plugged in the charger the fans are pulsing, not spinning only pulsing. so i started to check the power rails, and ppbus_g3h voltage keeps dropping. It will not stay a solid 12v , it drops to like 4v and spikes back to 12v. I checked current sensing resistors all of them, replaced isl chip same problem replaced transistors, i removed the fuse and checked pin 1 for a short no short i checked caps around area no short I'm completely lost. With fuse off i plugged in the charger and checked pin 1 for voltage same 12v droops to 4v and back up again no water damage board looks fine.What the hell could be the problem here. Please i need help.