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Apple's line of laptops for professional and power users. To date, the MacBook Pro line includes 13, 14, 15, 16, and 17-inch variants, with major revisions defined by Pre-unibody(Original), unibody, Retina display, Touch Bar, and SOC (system-on-a-chip) designs.

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820-2936 quarter fan spin

so to start out i dont specialize in mac repair, i mostly work on phones. but a friend of mine had an issue with their macbook so i figured id take a look at it.

so everything is disconnected but the board and dc in board. it shows a green light on the charger and fan starts to spin up then stops. i checked all the main power rails and i found one that isnt right. pp5v_s3 is missing and its weird, when the fan starts to spin it shows 5volts for a split second the 0 again, and if i hook power to the board then disconnect power and test the line is shows as .006 voltage drop in diode mode but if u keep the multimeter probes on it starts to rise until its at like .400 i went over the entire board under a microscope many times and also looked at it with ir camera. i dont see anything that looks terrible. but im stumped and am hoping one of the experts on here can point me in the right direction.

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You’ll need to spend sometime reviewing Louis Rossmann’s YouTube channel as he has documented a few different causes for your problem with a bad pp5v_s3. Get the schematics & board views so you can follow what he does and what trace or component needs to be repaired/replaced.

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2 Comments:

that was step 1...lol

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@mobilemedic - Step 2 is not down voting a fair answer!

Your expectation is we can tell you what competent has failed, thats just not humanly possible from afar. If I had your system in front of me I would take the exact steps I outlined to you.

Debugging a board is a process using the documentation and test gear to isolate out the failing component.

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lukerockhill will be eternally grateful.
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