Replacement motherboard capacitor

Seejay28

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Jan 13, 2014
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I was working on my friend's PC the other day, when I noticed there was a capacitor that had snapped off rattling around in the bottom of the case.

I'm going to have a crack at soldering in a new one, however I can't find an identical one to replace it with.

This is the one that had fallen off


Based on what is written on the top I've found this
http://uk.farnell.com/panasonic-electronic-components/16sepc270m/cap-alu-elec-270uf-16v-rad/dp/2354608

Would this capacitor be suitable? If it's any help, the motherboard is an Asus P8Z77.

Thanks!
 
You did a great job figuring out the part values: 270uF at 16V rating. The issue is what is the ripple current rating for the old part. In the Farnell datasheet, it shows that the ripple current for the new part you found is 5000mA (5A). That is pretty good, but there are some that have higher ratings.

I do power supply design and have come across problems like this before. A simple way to check if it is will work is how hot the cap gets when running. Depending upon where it is on the motherboard, it may feed the memory, a PCIe slot, chipset, etc. You need to find what it is running and load that subsystem (for memory, Memtest86+ works well). After about 10 minutes you can touch the cap top to see if it is too warm. But you should discharge any ESD from your hands into the case first before touching the cap! Touch the PC case to discharge any static electricity and then touch the cap, being careful because if the cap is too small, it will be very hot. If your room temp is about 23 deg C, it is ok if the cap is quite warm, but should typically not burn you with a short touch (2 sec). If there are other caps in parallel with that one, compare their touch temperature to the one you added. That is also a good sanity check.

You can also parallel smaller value caps with higher ripple ratings to get the ripple heating spread out. But that can be messy.

You sound like you might be voted most likely to become an engineer. :)

Good luck!