820-00292 No Power

brunomotter

Member
Hello! Got a 5K Late 2015 iMac here with no power. Tested with a known good PSU and nothing. No LEDs light up and no signs of life. I cannot find the schematics for that board anywhere not even for sale... Anyone here has the schematics for a board that has similar layout? The board had corrosion on an IC(or MOSFET, I can't know for sure because have no schematics) near the second bottom screw hole on top of the board, not the classic area near the USB ports where these Macs generally corrode(I live at a beach city, so there's a lot of sea air here).
 

brunomotter

Member
Well, I identified the chip and it's a little PWM controller... The problem is that 2 pads are fucked on the board. One of them corroded so much that it hit the underneath layer and shorted to GND, so I need a way to insulate it. I thought about using UV resin. Anyone here tried this already? If it's not possible than I will need to think another way to do this job. Initially I thought of glueing the component upside down with contacts facing up and wire each one of them to the other components on the board, but that would be a PITA to do and could cause the component to overheat as its central pad would not touch the PCB to spread heat...
 
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