1st gen. iMac G5 logic board: resistor question

Discussion in 'PowerPC Macs' started by Throbin, Aug 17, 2009.

  1. Throbin macrumors newbie

    Aug 17, 2009
    Hi all, new to the forums (and Mac, as well!)

    I just got a first generation G5 iMac dirt cheap, and it has the infamous popping capacitors problem. No big problem, I've got friends who can handle this. I get them a kit of caps and they solder them in for me (and get a case of beer - but I digress).

    However, while scanning the logic board for other problems, they came across two apparently missing resistors; namely R3316 and R3313. I have arrowed the resistors in the attached .jpg. Also missing is C3470 (obviously missing at the top right hand corner of R3317). Does anyone know which resistors I should get for R3316 and R3313, and which capacitor for C3470?

    Any advice welcome!


    Attached Files:

  2. MTI macrumors 65816

    Feb 17, 2009
    Scottsdale, AZ
    Don't sweat it. All Apple logic boards have unused component locations screened on them. I'll be you'll even find some unused cap locations.

    Unless there's signs of removal (scratches, heat marks, uneven solder pads) of a component, it's just an used spot.
  3. belvdr macrumors 603

    Aug 15, 2005
    No longer logging into MR
    MTI, take a look at that photo. It isn't just unused components.

    OP, have you google for schematics for that model?
  4. zmttoxics macrumors 65816


    May 20, 2008
    They aren't missing, per say. Often in computers, there are junctions left open for use between models to set different settings (speed, locks, who knows). Yours just happens to not need those set. :)
  5. rtrt macrumors 6502a

    Jan 19, 2008
    agree with belvdr - click on the larger version - someone has modified that board post purchase.

    I wouldn't be surprised if that machine was toast - but then if you have access to friends who can work on logic boards - maybe you'll be fine
  6. MTI macrumors 65816

    Feb 17, 2009
    Scottsdale, AZ
    Okay, I took a look at the larger image and 1) the soldering is extremely sloppy on those surface mount resistors and one is missing, given the burn marks.
  7. Throbin thread starter macrumors newbie

    Aug 17, 2009
    Thanks for all the replies, people!

    The sloppy soldering is what roused our suspicion in the first place. We think some hack tried to replace the caps (some are replaced) but he just gave up. Not a very bad decision, considering his soldering skills :D

    I've Googled until my face was as blue and white as my G3, but I don't seem able to find a schematic anywhere. Any pointers to a schematic online somewhere?

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