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Mid 2012 model, A1278 / 2.5 GHz i5 or 2.9 GHz i7 processor.

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820-3115 board- Can I remove Q3880 and U3890 on the logic board?

Hey everyone-

I’m kind of new to board-level repair. I have an 820-3115 macbook pro board here, it had no power due to water damage. After replacing a few capacitors, I found that removing Q3880 allowed the machine to function properly again. The schematic shows that Q3880 is on the T29 boost circut, and when I replaced Q3880 it caused U9410 to blow. I am fine with not having thunderbolt on this machine, and it looks like Q3880 is a transistor for thunderbolt. My question is: Can I remove Q3880 and U3890 which is the thunderbolt controller once I replace U9410 and still have everything but thunderbolt work properly? U3890 is very corroded around the edges.

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@smencimer there is a lot going on with your board. You could try and narrow down where the short is on your board etc. and use your schematic to see what the Apple engineers originally concocted. Of course since you already know that it works (sans Thunderbolt) and you want to see if it works with your mod, I’d go ahead and do it. The result will be interesting to find out, so let us know.

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Thanks! I went ahead and removed U9410, U3890, and Q3880. Board seems to work fine minus the IC0R sensor which I dropped on the floor and can't find (coming in the mail tomorrow). The IC0R sensor was heating up after I replaced it, so was going to see if there was some solder touching 2 pins together. Do you happen to know if that's a common issue? The only error AHT gave me was the IC0R sensor (presumably because it's not there) so I think the rest of the board is OK.

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Have not heard or found anything that would make the heating of IC0R sensor common. Makes sense that you would get an error with AHT on a missing sensor. Really interesting and hope it will all work out for you. Keep us updated.

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Sam Mencimer will be eternally grateful.
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