SMT Capacitor broken off

[Xplora]

Hi,

A Gigabyte 430 GT minus one SMT Capacitor:

I have a Mini-ITX system "Lian-Li, Pc-Q7" and "Zotac H55 C-E" with one PCIe slot.
Needless to say it's a pain putting this mini together ;-)
(especially with a full-sized power supply).

After cleaning the system I struggled to lower the 430 into place and it got stuck on the edge of the CPU fan cage and one capacitor came loose :-(
The capacitor went missing unfortunately.

It's one of the very small (about 1mm) capacitors near the bottom which is
soldered between the GPU and the PCIe slot contacts.
They are placed together as pairs on the back of the card.

I don't have solder paste neither a replacement capacitor unfortunately. I do have a older AGP card with slightly larger capacitors, but I don't know if one of them will suffice since the card is obviously built using another process.

Would my local IT shop be able to repair the 430 for me,
and how much will it cost?

Thanks.

 

[bryanl]

Would my local IT shop be able to repair the 430 for me,

It's almost always the worst possible choice since IT shops rarely do component repairs or have any soldering skills. A TV or audio repair shop would be much better.

Assuming there are 31 capacitors identical to the one that broke off, it's a coupling capacitor in the range of 100 nf (0.1 uF). Use a 10-15W soldering iron and tweezers.

 

[Xplora]

fantastic, yes there are 31 identical capacitors to that one that broke off.
This is my soldering iron (about I'd say a 1mm tip, and the heat can be adjusted)
http://shop.rabtron.co.za/catalog/oryx-soldering-iron-p-5389.html

Here is a pic of the board:

thanks bryanl.

 

[SecurityTheatre]

Surface mounts like that are tricky. I don't have anything else to offer other than advice to make sure whoever does it has experience with that sort of thing.

Your local PC shop won't.

 

[paul878]

That solder iron look like way too big (size of the tip) for the job. You want something a lot smaller. You want something like this

http://www.amazon.com/Weller-WM120-1...d_sim_sbs_hi_2


The card might work fine without that little caps give it a try first.

 

[Colt45]

I use a fairly large tip usually... I put the tip along the length of the cap, so you can solder both ends at once / adjust things.

Make sure you take off the broken termination bits before you try and solder on a new one, or you'll have trouble getting it flat..

 

[Mark R]

The missing capacitor is a coupling capacitor for a PCI-E signal. The card will not run correctly without it, so leaving it off is not an option.

However, the value isn't particularly critical. It's just there to block DC voltage from the PCI-E transmitter. Just aim for around 100 nF. If you're really paranoid about the value being wrong, swap out its partner at the same time, so that the two capacitors on the same lane are matched.

 

[William Gaatjes]

fantastic, yes there are 31 identical capacitors to that one that broke off.
This is my soldering iron (about I'd say a 1mm tip, and the heat can be adjusted)
http://shop.rabtron.co.za/catalog/oryx-soldering-iron-p-5389.html

Here is a pic of the board:

thanks bryanl.

Those capacitors are very probable the same value.
If you want to know the value, just solder the capacitor next(other lane) to it from the board and measure that capacitor. Ceramic capacitors cannot withstand instantaneous temperature risings and might crack . Be sure to use the solder tin as the medium to transfer the heat and not the soldering iron itself.


You might want to read this for background information :
http://www.ami.ac.uk/courses/topics/0179_fmcc/index.html

http://forums.anandtech.com/showthread.php?t=2250963&highlight=ceramic+capacitors

 

[john3850]

What would happen if you jumped it out with a silver pen or even a heavy pencil to try it before soldering .

 

[PottedMeat]

What would happen if you jumped it out with a silver pen or even a heavy pencil to try it before soldering .

maybe physically nothing, maybe a damaged transmitter or receiver on the motherboard or board or both -> at the very least it won't run right

The missing capacitor is a coupling capacitor for a PCI-E signal. The card will not run correctly without it, so leaving it off is not an option.

However, the value isn't particularly critical. It's just there to block DC voltage from the PCI-E transmitter. Just aim for around 100 nF. If you're really paranoid about the value being wrong, swap out its partner at the same time, so that the two capacitors on the same lane are matched.

edit: looks like it just won't run right

4.3.5.3. Short Circuit Requirements
All Transmitters and Receivers must support surprise hot insertion/removal without damage to the
component. The Transmitter and Receiver must be capable of withstanding sustained short circuit
to ground of D+ and D-.

 

[john3850]

The missing capacitor is a coupling capacitor for a PCI-E signal. The card will not run correctly without it, so leaving it off is not an option.

However, the value isn't particularly critical. It's just there to block DC voltage from the PCI-E transmitter. Just aim for around 100 nF. If you're really paranoid about the value being wrong, swap out its partner at the same time, so that the two capacitors on the same lane are matched.

When I read the above missed {It's just there to block DC voltage}

 

[Xplora]

Phew, right guys ... it's working so far - albeit without a new capacitor, in fact I just closed the path with solder, so I'll see what happens ...

I put the (interchangeable) solder tip in my drill and sanded it to nice thin point! (nuts though, but I still have other sizes).

GPU temps are around 45 degrees celcius

I left out a pic of the soldered work, because it's, well... not perfect ;-)
Thanks very much for expert input.
I'll let you know if something scary happens ;-)

 

[Xplora]

That solder iron look like way too big (size of the tip) for the job. You want something a lot smaller. You want something like this

http://www.amazon.com/Weller-WM120-1...d_sim_sbs_hi_2


The card might work fine without that little caps give it a try first.

The card might work fine without that little caps give it a try first.

Yes indeed ... thanks

 

[Xplora]

Those capacitors are very probable the same value.
If you want to know the value, just solder the capacitor next(other lane) to it from the board and measure that capacitor. Ceramic capacitors cannot withstand instantaneous temperature risings and might crack . Be sure to use the solder tin as the medium to transfer the heat and not the soldering iron itself.


You might want to read this for background information :
http://www.ami.ac.uk/courses/topics/0179_fmcc/index.html

http://forums.anandtech.com/showthread.php?t=2250963&highlight=ceramic+capacitors

Fantastic ... Very detailed information ... thank you William.