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MacDann

macrumors 6502a
Original poster
I was working on a friend's cMP 4,1 single processor machine recently when I noticed something about the motherboard.

Along side the CPU socket are a number of small, square devices arranged in a straight line. There appears to be some sort of relationship with the heat sink for these, as there looked to be a piece of foam tape or other material along the heat sink that comes into contact with these devices when the heat sink is in place.

I noted these as there appeared to be what looked like evidence of liquid or something on the motherboard in this area as well. I didn't attempt to clean it off, but I had some concerns about what it was and how it might relate to these devices, thinking they might be capacitors and they were leaking.

I've attached a picture to identify what I'm talking about. What are these, and is their proximity/relationship to the heat sink critical?

MacDann
mp41mb.JPG
 
I think this is rather normal, I have seen it on most of CMP's I have opened up.
Not sure if it's solder flux or some type of thermal compound residue, not leaky caps though.
But just ignore it and everything should be fine. You will do more harm than good trying to scrub it off.
 
I was working on a friend's cMP 4,1 single processor machine recently when I noticed something about the motherboard.

Along side the CPU socket are a number of small, square devices arranged in a straight line. There appears to be some sort of relationship with the heat sink for these, as there looked to be a piece of foam tape or other material along the heat sink that comes into contact with these devices when the heat sink is in place.

I noted these as there appeared to be what looked like evidence of liquid or something on the motherboard in this area as well. I didn't attempt to clean it off, but I had some concerns about what it was and how it might relate to these devices, thinking they might be capacitors and they were leaking.

I've attached a picture to identify what I'm talking about. What are these, and is their proximity/relationship to the heat sink critical?

MacDannView attachment 800581
These are the power circuits for the 6 power lines of the processor. It's thermal pad oily decay. You can clean with IPA.
 
Thanks, everyone! Is it important to replace the thermal pad on the heat sink for these devices? I would think that it has aged somewhat and may not be making good contact as it was when new. If they don't have good contact can they overheat and fail?

MacDann
 
Thanks, everyone! Is it important to replace the thermal pad on the heat sink for these devices? I would think that it has aged somewhat and may not be making good contact as it was when new. If they don't have good contact can they overheat and fail?

MacDann
Yes you need to replace it, it's crucial to cool the power circuit. Someone posted a replacement here sometime ago.
 
If I remember correctly, was in the @handheldgames thread about replacing a 2009 backplane/tray combo for a 2010 one.
[doublepost=1541167312][/doublepost]Easy 4,1 dual CPU upgrade?

I found another thread that pointed at eBay as a source - there's all kinds of the stuff there. It seems that the material on the 4,1 heatsink is pretty thick as I recall, maybe a couple of millimeters. Next time I have one apart I'll look more closely and see so I can get some and have it on hand for future work.

Again, thank you!

MacDann
 
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