Help Identifying chips on Gigabyte GA-Z68XP-UD3 and possible PCI express problem

Aug 27, 2018
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I have a Gigabyte GA-Z68XP-UD3 yesterday while testing a new power supply I smelled burning. After removing everything but the CPU & RAM the PC will power up and POST just fine. However if I plug up the HDMI to the motherboard port I get video, if I put my GTX 980 in the PCI Express nothing. The card will power on and fans are spinning but I will never get video.

Under the top PCI Express slot there are 4 black chips. The third chip looks different and after turning on the PC it becomes instantly hot enough to burn you. I believe that this would be the problem and guessing that I need a new motherboard. However I would like to know if anyone knows what these chips are for?

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engineer5261

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Apr 26, 2016
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Post a picture and perhaps the component can be identified but the truth is if its anything more complicated than an SMT cap or resistor we may only be able to guess at what it is as IC's do not always have markings and sometimes motherboard manufacturers (or any other electronics manufacturer) request the semiconductor company to provide chips without identification markings (if any are present in the first place) to keep others from reverse engineering their product.
 
Aug 27, 2018
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Sorry tried to post the first time but it didn't take.
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Aug 27, 2018
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Text on the chip is - asmedia - ASM1480 - B4M21434A0 1153
I am trying to get a good picture of it if you still need that.
 
Aug 27, 2018
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Thanks I didn't see the chip had text, I think I found the answer.

ASM1480 is a 16 to 8 channel multiplexer / demultiplexer Switch with Hi-Z outputs. This device is a bi-directional multiplexes differential signal to one of two corresponding outputs. This design is suitable for current high-speed application up to PCI-Express Rev.3.0

So I am guessing that is the reason that my video card isn't working.
 

engineer5261

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Apr 26, 2016
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Yeah, that's a multiplexer IC to figure out which PCI port to communicate with as there can be many devices sharing the PCIe bus.

I've looked this up and people have had issues with these IC's. See this thread http://

You can forget about ordering extra IC's and replacing them as these are 44-pin TQFN IC's, that's thin quad flat no leads - which means near impossible to hand solder it as the pads are on the bottom. These are normally soldered on the board using infrared ovens and industrial soldering machines.

Other than the high temperature, do you see any burn marks on the board around the IC?

Do you have integrated graphics on your CPU? You could use that to confirm the theory that one or more of these multiplexer IC's are faulty.
 
Aug 27, 2018
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Yes the chips that is getting really hot looks damaged, and I was able to verify I believe. My motherboard does have integrated graphics and when I use them it will work fine. But when I place a video card in that PCI Express slot I get no video at all.

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engineer5261

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Aug 27, 2018
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OK thanks for the help. It was basically the info about the chips that I was wanting. And trying to make sure that my video issue may be related to these chips. Thanks again for the info and help. They board is older so it looks like it time to upgrade.