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]( "maxresdefault.jpg")
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Broke a piece off logic board on Mac Pro. What is it?
- Thread starter garyleague
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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.
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!
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I took another picture. Hope this one is clearer. The circled thing came off on one of the boards. Thanks again!
[doublepost=1456117240][/doublepost]Also here is board where it came off.
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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.
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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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.
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.
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.
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.
English please? Lol. I have no idea what that means...or why it's important.
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Couldn't you go to apple store and have them replace it?
There does not appear to be any thermal relief on the ground side, so a small soldering pencil is not sufficient.
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.
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.
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.
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.
Has to still have silver at both ends though.