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garyleague

macrumors newbie
Original poster
Feb 21, 2016
3
0
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
 

JoeG4

macrumors 68030
Jan 11, 2002
2,872
539
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.
 
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T5BRICK

macrumors G3
Aug 3, 2006
8,314
2,387
Oregon
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?
 
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garyleague

macrumors newbie
Original poster
Feb 21, 2016
3
0
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?

Here it is up close. The circled thing came off on one of the boards. Thanks so much for your help!
pic2.jpg

[doublepost=1456116705][/doublepost]
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.

I took another picture. Hope this one is clearer. The circled thing came off on one of the boards. Thanks again!
pic2.jpg

[doublepost=1456117240][/doublepost]Also here is board where it came off.
pic3.jpg
 
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RetroDan

macrumors regular
Dec 17, 2015
112
150
Michigan
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.
 
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garyleague

macrumors newbie
Original poster
Feb 21, 2016
3
0
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.

Thank you for your response. So far there's no notable difference - do you know the consequences of me leaving it as it is?
 

RetroDan

macrumors regular
Dec 17, 2015
112
150
Michigan
Thank you for your response. So far there's no notable difference - do you know the consequences of me leaving it as it is?

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.
 
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MacVidCards

Suspended
Nov 17, 2008
6,096
1,056
Hollywood, CA
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.
 

pat500000

Suspended
Jun 3, 2015
8,523
7,515
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.
English please? Lol. I have no idea what that means...or why it's important.
[doublepost=1456209088][/doublepost]
Here it is up close. The circled thing came off on one of the boards. Thanks so much for your help! View attachment 617728
[doublepost=1456116705][/doublepost]

I took another picture. Hope this one is clearer. The circled thing came off on one of the boards. Thanks again!
View attachment 617729
[doublepost=1456117240][/doublepost]Also here is board where it came off.
View attachment 617731
Couldn't you go to apple store and have them replace it?
 

box185

macrumors member
Sep 12, 2013
65
3
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.

There does not appear to be any thermal relief on the ground side, so a small soldering pencil is not sufficient.
 

RetroDan

macrumors regular
Dec 17, 2015
112
150
Michigan
English please? Lol. I have no idea what that means...or why it's important.

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.
 
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pat500000

Suspended
Jun 3, 2015
8,523
7,515
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.
Oh ok that makes sense.would that damage other components of the computer?
 

RetroDan

macrumors regular
Dec 17, 2015
112
150
Michigan
Oh ok that makes sense.would that damage other components of the computer?

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.
 

AidenShaw

macrumors P6
Feb 8, 2003
18,667
4,677
The Peninsula
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.
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.
 
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