Broke a piece off logic board on Mac Pro. What is it?

Discussion in 'Mac Pro' started by garyleague, Feb 21, 2016.

Tags:
  1. garyleague macrumors newbie

    Joined:
    Feb 21, 2016
    #1
    Could someone please help me identify the piece (circled in the picture below)? And should I worry about replacing it? Very much appreciate it.

    maxresdefault.jpg
     
  2. JoeG4 macrumors 68030

    JoeG4

    Joined:
    Jan 11, 2002
    Location:
    Bay Area, Ca.
    #2
    The good news is that's a video card. Bad news is looking at the picture I can't even see what the component is. Can't tell if that's a power regulator or not.
     
  3. T5BRICK macrumors 604

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #3
    Looks like a diode but I can't really tell. It's also possible that the SMT pads were damaged when the part was knocked off. Can you get a closer picture of the logic board(or graphics card) and the part itself?
     
  4. garyleague, Feb 21, 2016
    Last edited: Feb 21, 2016

    garyleague thread starter macrumors newbie

    Joined:
    Feb 21, 2016
    #4
    Here it is up close. The circled thing came off on one of the boards. Thanks so much for your help! pic2.jpg
    --- Post Merged, Feb 21, 2016 ---
    I took another picture. Hope this one is clearer. The circled thing came off on one of the boards. Thanks again!
    pic2.jpg
    --- Post Merged, Feb 21, 2016 ---
    Also here is board where it came off.
    pic3.jpg
     
  5. RetroDan, Feb 22, 2016
    Last edited: Feb 22, 2016

    RetroDan macrumors newbie

    RetroDan

    Joined:
    Dec 17, 2015
    Location:
    Michigan
    #5
    Whatever it is, it's connected to ground. Based on the package style, I'm going to guess that it's a non-polarized polymer cap of some kind.

    You might be able to re-attach it if you add some fresh solder blobs to the contact points on the board and then, using a pair of tweezers to hold the component in place, using a very hot soldering iron to repair the connection. Be sure to unplug the nMP's power cable and discharge all residual power in the caps by pressing the power button when unplugged before you attempt this.
     
  6. garyleague thread starter macrumors newbie

    Joined:
    Feb 21, 2016
    #6
    Thank you for your response. So far there's no notable difference - do you know the consequences of me leaving it as it is?
     
  7. RetroDan macrumors newbie

    RetroDan

    Joined:
    Dec 17, 2015
    Location:
    Michigan
    #7
    It looks like the only thing it's in-line with is a choke and a pull-down resistor, so I'm going to say that my initial guess of it being a poly cap is correct. It appears that component is the last stage of a discharge circuit.

    Good to hear that its absence doesn't noticeably impact things, but I would still recommend its repair, if not by you, then by an authorized tech. Because that missing component looks to be the last thing in a chain between voltage and the majority of the ground plane, yeah, I'd replace it. It might be there solely for energy dissipation, so its absence could cause the components on its rail to overheat. In something as expensive as a Mac Pro, I think it would be worth the time, effort, and paranoia to have it repaired ASAP.
     
  8. box185 macrumors member

    box185

    Joined:
    Sep 12, 2013
    #8
    Looking at the TI data sheet ( Fig. 46 ) for the the TPS54622, the missing part appears to be the Output Filter Capacitor.

    http://www.ti.com/lit/ds/symlink/tps54622.pdf

    Based on paragraph 8.2.2.3 Output Capacitor Selection in the data sheet, this part is important.
     
  9. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #9
    As long as the part doesn't have the silver metal part ripped off either end, it can be easily soldered back on by anyone competent with a small soldering pencil.
     
  10. pat500000 macrumors 603

    pat500000

    Joined:
    Jun 3, 2015
    #10
    English please? Lol. I have no idea what that means...or why it's important.
    --- Post Merged, Feb 22, 2016 ---
    Couldn't you go to apple store and have them replace it?
     
  11. box185 macrumors member

    box185

    Joined:
    Sep 12, 2013
    #11
    There does not appear to be any thermal relief on the ground side, so a small soldering pencil is not sufficient.
     
  12. RetroDan macrumors newbie

    RetroDan

    Joined:
    Dec 17, 2015
    Location:
    Michigan
    #12
    The paragraph in question basically means that power may spike under certain situations, and the cap is supposed to be there to catch and briefly store the excess power. When that cap isn't there, that power spike has nowhere to go, kinda like plugging the drain in your bathtub, and so it backs up into the path of least resistance...which in this case refers to the components it can reach. The potentially sensitive-to-power-spikes-of-this-nature-that-the-capacitor-in-question-is designed-to-protect components.

    So, to sum up, BAD JUJU.
     
  13. DanielCoffey macrumors 65816

    DanielCoffey

    Joined:
    Nov 15, 2010
    Location:
    Edinburgh, UK
    #13
    Do you have AppleCare+ with the Accidental Damage cover?
     
  14. pat500000 macrumors 603

    pat500000

    Joined:
    Jun 3, 2015
    #14
    Oh ok that makes sense.would that damage other components of the computer?
     
  15. RetroDan macrumors newbie

    RetroDan

    Joined:
    Dec 17, 2015
    Location:
    Michigan
    #15
    It's pretty likely that it could, yeah. It's also entirely possible that the signal chain is smoothed out to nothingness by this point, rendering voltage spikes a near impossibility. I don't know - Apple does tend to be picky with redundancies on stuff like that, but it's not a certainty. I don't have a nMP to trace the path, so I can't speak with absolute authority. Stuff on PCBs does tend to be there for a reason.
     
  16. AidenShaw macrumors P6

    AidenShaw

    Joined:
    Feb 8, 2003
    Location:
    The Peninsula
    #16
    In English.

    Unplug the system, and do not plug it back in until the GPU is replaced.

    You broke off a piece that protects the system from voltage spikes. It shouldn't be necessary to explain why running without that protection is a very, very risky thing.
     
  17. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #17
    If you are in LA and bring it by I'll put the piece back on for free, just to shut this thread down. I have 2 Hot Air stations and a dozen or so soldering irons.

    Has to still have silver at both ends though.
     

Share This Page