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I have a MacBook Pro 820-3115-B. There is no water damage and the customer brought it in for a thermal paste cleaning. I changed the paste and put it all back together to find out they no longer have backlight… The LDVS Cable has no damage nor the connector as I checked all the pins for damage…. I shined a light from the back and you see a image just no backlight… Anyways, I am very little experienced in board level repairs and reading schematics but I did check the fuse… I thought it was that an I removed and ran a micro wire for testing and still no backlight.. However though the fuse reads when turned on and booting 11.7volts which I thought should be 12.5 volts I also tested: Capacitor C9710 1 Pin, the voltage is 5V R9731 and R9715 to split voltage, the voltage measured is 2.9volts Measure the resistor R9704 2 Pin, it has 3volts I am not sure if U7901 IC Is blown for some odd reason. I take these MacBooks apart all the time and never had this issue…. Can someone guide me fixing this and what else to check….. I don’t know what else to do
I have changed you to the correct icon according to your logic board. 820-3115-B 820-3115 2012 2.5 i5 Apple Motherboard 661-6588 MacBook Pro 13"
i did solder the top resistor back to where it belonged as I noticed it touching the bottom one that most likely caused the short and killed the u9701 chip. I’m assuming overtime the resistor got loose and touched the other one and that did it… so now u9701 cannot boost to 25 volts..
