My cap fell off!

funkydmunky

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My arcade cabinet powered by my AM2+ setup was being wonky and just all around trouble so I decided a full dissemble with a good cleaning and re-paste with a check for any obvious problems was in order. When cleaning the MB Gigabyte GA-MA790GP-DS4H of dust with a soft bristle tooth brush, a tiny capacitor just fell off.
The only thing written on the cap is 829 10 10. Each set of numbers on their own row.
The cap was in a set of three located just below and to the left of where it is writen PCB MADE IN TAIWAN. Next to the missing cap is written CEC39. The next one is labeled CEC38 and the third CEC19.
Question. Anyone know where I can buy a replacement? And or should I see if it will boot without or is that a stupid idea?

As always any help or advice is appreciated.
thumbnail_IMG_20210409_214720332.jpg
 

toast0

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If you've got a multimeter with a capacitor test, you could try that with the capacitor that fell off. If I'm doing it right, 829 should mean it's 8.2 pico farrad. If you get a similar reading, I'd just stick it back on (well I wouldn't, I can't solder that small). I'd guess one of the 10s means the cap is rated for 10V, not sure about the other one.

I'm guessing the capacitor is related to the sound card, because it's between the sound chip and the lan chip, and stuff nearer to the lan chip is labeled Lxx, and stuff closer to the audio chip (maybe codec chip) is Cxx. CEC is probably Codec Electrolytic capacitor; i see CDx which look like diodes and CQx which are transistors (the Q is silent), CU1 is the codec microchip. I can't find electrolytic capacitors with only 8.2 pF though, so maybe I screwed something up. Also, some of your traces up top there look pretty beat up.

What kind of weirdness were you having? My guess is worst case if you boot it without the capacitor, the codec chip catches fire and ruins your board; but most likely, something in the audio path just doesn't work right, possibly subtly (or something in an audio path that you're not even using).
 

StormNobleheart

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Appears that some thing caused physical damage to the PCB and may have knocked the capacitor off. I would attempt to find the schematics of the board to discover what the capacitor does before risking the CPU. You can probably enter the type in a search engine to find where to buy a replacement. How much experience with solder rework do you have?
 

funkydmunky

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If you get a similar reading, I'd just stick it back on (well I wouldn't, I can't solder that small).
The cap legs were bent flat on the underside, by design, and sat in the solder trenches. A plastic holder was glued to the board keeping the legs pressed tight to the board. From close examination it appears this glue wore off and the cap fell off with my light brush stroke around it. Cap looked perfect and while I was planning my re-glue one of the legs just fell off. Very brittle.
 

funkydmunky

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Appears that some thing caused physical damage to the PCB and may have knocked the capacitor off. I would attempt to find the schematics of the board to discover what the capacitor does before risking the CPU. You can probably enter the type in a search engine to find where to buy a replacement. How much experience with solder rework do you have?
The damage to the board is very superficial and just from years of the GPU being removed dozens of times and you almost can't see it with a non magnified look. The clearance should not have allowed contact with that cap but it could have got bumped over the years for sure. From my examination it looks as if the black plastic cover holder only had glue on one side. It appears that it wasn't even soldered, just pressed into contact and held by that cover. My brush was enough contact for it to just fall off. Just waiting for the slightest touch.
I had always thought that the cap legs had to penetrate the board.
 

StormNobleheart

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I never liked surface mounting through-hole components. If you have the equipment and experience, I would solder the legs to the pads instead of just glue.
 

Nobu

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There appears to be a lot of yellow stuff on that pcb. You haven't put any flux on there, have you? Could be a cap leaking out somewhere?
 

p05ta1

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Maybe time for a upgrade. Seeing all the scratches on the pcb is alarming.
If you have a system laying around maybe it has a better cpu and chipset than am2+
 

RazorWind

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This type of capacitor is notorious for leaking, and because the electrolyte inside is acidic, it tends to damage the board. There is something on the board that may be leaked electrolyte (could also just be old conformal coating). If it's electrolyte, you should clean that off before attempting any further repairs. The pads it goes on look OK, so if you have access to the right equipment, it should be easy peasy to replace it. The hard part will be determining for sure what spec it is.

Can you get a better photo that shows the markings on the cap that fell off? Also, can you measure the dimensions of the cap that fell off, preferably with a vernier caliper?

If you happen to be local to me in Austin, Texas, I'd be happy to solder a new one on there for you, if you're not equipped to do this yourself.
 

Burticus

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The cap is right next to the ALC audio chip... so I say fire it up and turn off the onboard sound and see what happens. Surely you are doing sound via an hdmi output video card? if not... usb sound card for $10? or just buy a new mobo + cpu for $100

AM2+... what are you running, a Phenom 2? $100 upgrade here would be a huge upgrade, but then again how much does one need to run pacman and dig dug
 

GiGaBiTe

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If you've got a multimeter with a capacitor test, you could try that with the capacitor that fell off. If I'm doing it right, 829 should mean it's 8.2 pico farrad. If you get a similar reading, I'd just stick it back on (well I wouldn't, I can't solder that small). I'd guess one of the 10s means the cap is rated for 10V, not sure about the other one.

"829" is either a date code or a manufacturer code. Those are 10uF capacitors rated at 10 volts, as shown by the "10" "10" markings under the 829. The other capacitors confirm it, there are two 100uF 16v rated caps right below it next to the audio connector.

I'd be more worried about those damaged traces, that motherboard took some serious abuse to gouge down to the copper traces. The masking is really tough to scratch that deep. If the traces are still unbroken, I'd use some clear nail polish to seal the gouges so the copper doesn't oxidize and cause problems.

But I agree with Razorwind, SMD electrolytics are junk, especially 90s era ones, they've all leaked by now. Them falling off the board is a sign of leaking, the corrosive electrolyte eats the legs to the point where the whole capacitor just falls off.
 

toast0

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"829" is either a date code or a manufacturer code. Those are 10uF capacitors rated at 10 volts, as shown by the "10" "10" markings under the 829. The other capacitors confirm it, there are two 100uF 16v rated caps right below it next to the audio connector.
And that's why I'm in software ;) I only know enough EE to get myself in trouble.
 

funkydmunky

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There appears to be a lot of yellow stuff on that pcb. You haven't put any flux on there, have you? Could be a cap leaking out somewhere?
No I have not done any work on the board so no flux. No evidence of a leaking cap.
 

funkydmunky

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This type of capacitor is notorious for leaking, and because the electrolyte inside is acidic, it tends to damage the board. There is something on the board that may be leaked electrolyte (could also just be old conformal coating). If it's electrolyte, you should clean that off before attempting any further repairs. The pads it goes on look OK, so if you have access to the right equipment, it should be easy peasy to replace it. The hard part will be determining for sure what spec it is.

Can you get a better photo that shows the markings on the cap that fell off? Also, can you measure the dimensions of the cap that fell off, preferably with a vernier caliper?

If you happen to be local to me in Austin, Texas, I'd be happy to solder a new one on there for you, if you're not equipped to do this yourself.
There is a square black plastic cap holder bellow each cap. It holds the cap in place allowing the legs through then was glued to the board. What you see on one side of the empty cap is the reminents of this glue. There is none one the other side and think that is why it fell off after all these years with minimal touch.
 

Nobu

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There is a square black plastic cap holder bellow each cap. It holds the cap in place allowing the legs through then was glued to the board. What you see on one side of the empty cap is the reminents of this glue. There is none one the other side and think that is why it fell off after all these years with minimal touch.
I'm afraid that "glue" may in fact be electrolyte from the capacitor. I'm not aware of any assembly of motherboard components which involves gluing them in place. From what I remember, those black things are stabilizers, and are simply there to prevent the cap from being pushed around, to protect the delicate legs from being bent and damaged. The legs should have been soldered in place.
 

funkydmunky

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I'm afraid that "glue" may in fact be electrolyte from the capacitor. I'm not aware of any assembly of motherboard components which involves gluing them in place. From what I remember, those black things are stabilizers, and are simply there to prevent the cap from being pushed around, to protect the delicate legs from being bent and damaged. The legs should have been soldered in place.
That very well could be the case. When it fell off the legs were perfectly fine on the cap. Only a bit of what I assume was glue on the one side of the "stabilizer". It seemed to me that it wasn't even soldered in by mistake and was only held into contact by the glued stabilizer. Of course I know nothing of these matters and was all an observational assumption.
I will try disabling onboard audio as i do not user it and give it a go.
 

GiGaBiTe

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There is a square black plastic cap holder bellow each cap. It holds the cap in place allowing the legs through then was glued to the board. What you see on one side of the empty cap is the reminents of this glue. There is none one the other side and think that is why it fell off after all these years with minimal touch.

Incorrect. The yellow substance that has leaked down the board is electrolyte from the capacitor, it is not glue. SMD glue is red, and only a tiny dot of it is used, when used at all.

HTB1ThjQm2iSBuNkSnhJq6zDcpXaQ.jpg

Glue is usually not used on SMD electrolytic capacitors, unless the board they're on is double sided. There is definitely no SMD glue on this board.

The cap that fell off, in addition to the other two that did not have leaked significant amounts of electrolyte, you can see it all the way to the mounting hole on the board. And that's only what we can see in the picture, I have a feeling it has gone much farther than that.
 
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