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underwaterpilot

macrumors newbie
Original poster
Dec 16, 2022
1
0
I am attempting to repair my wife's Macbook Pro (A2251). I know that the RAM is bad and I was initially just getting ready to remove and reball the BGA chips.

Upon initial inspection I realized that it looked like there were two resistors missing on the logic board (highlighted below).
logic_board_main.jpg


logic_board_resistors.jpg


I got the board schematics (attached) and it looks like there should be a resistor there. I am new to looking at these drawings and don't know whether these resistors are configuration dependent or if they are actually missing. In the drawing they are the R2391_3 and R_2391_4 resistors.

I am looking to see:
  • Should these resistors actually be there?
  • What kind of resistors are they? (Not clear to me based on the drawings.... I have dealt with electical drwaings but this format is new to me)
Any help is appreciated! Also attached applicable drawing pages. Zip file contains applicable drawings and .brd file
 

Attachments

  • 820-01949 (dragged).pdf
    161.2 KB · Views: 153
  • Screenshot 2022-12-16 at 10.04.43 PM.png
    Screenshot 2022-12-16 at 10.04.43 PM.png
    226.2 KB · Views: 87
  • 820-01949.brd.zip
    193.6 KB · Views: 68

f54da

macrumors 6502a
Dec 22, 2021
504
185
If you don't get a response here, you might also consider posting on louis rossman's forum (requires a small fee to sign up though, presumably to cut down on useless posts). The readers there are likely to be more familiar with the board-level schematics.
 
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