Help to identify a blown cap

[woaimi]

Hi there,
I'm totally new to this forum and not sure if this is the right place to ask my question, if it's not please kindly move the thread to the right forum. Thank you

I have a Gateway 9550 series laptop. I had a problem with powering up the laptop and later found out it was 1 device mounted right behind the AC adapter jack had blown. It's one of those Surface Mount device and I suspected that is a capacitor. I don't have my camera at this time so I cannot take any picture but I will do that as soon as I can to give you more info. There is a printed code on the board that said C433 I'm not sure if that the real code for it or just the number put on by manufacture. Gateway quoted me $250 for the new board but I thought that I should try this first cause it doesn't cost much and that I had nothing else to lose on this board so there is no worst case.

All suggestion are appreciated. Thanks for helping

[willawake]

Re: Help to identify a blown cap

it is probably a cap. here is a pic where you can see caps and resistors. The resistors are black with a number on them and marked with R01 etc. The caps are marked with CB01 etc or on other parts of the board C01. One of the guys here will help better cos i am not so knowledgeable in smt components.

not so easy to replace although it is possible. what is your soldering experience?

it will be best to show some pics of the board though to see if there is other damage.

[PeteS in CA]

Re: Help to identify a blown cap

Those SMT MLCCs can be very brittle, especially larger form-factor types, when under mechanical stress (board flexing). "We hates them, Precious, we hates them!" But they are small, and have fairly high capacitance with low impedance. Unless you have one that is marked with a value (e.g. "103" = .01uF, "224" = .22uF, "105" = 1uF) - not likely - if it's a decoupling cap, I'd figure what the applied DC voltage is, what its size is, and get the largest capacitance in that case with a voltage rating at least double the applied voltage. If it's in a timing circuit, you need to find out what the value should be.

[kc8adu]

Re: Help to identify a blown cap

iirc its a 22uf@25v smt tantalum.
they usually fail with a bang and flash when the polarity is reversed.
oh and they stink too.
i strip them from scrap boards as they sub well for smt lytics.

[PeteS in CA]

Re: Help to identify a blown cap

Tantalum Unless they've changed in the last few years, Sun Microsystems will not use tantalum caps in their products, and require the same of their vendors.

Kemet has a series that is supposed to be less susceptible to sudden failure, http://kemet.com/kemet/web/homepage/kechome.nsf/vapubfilesname/F3102T495.pdf/$file/F3102T495.pdf .

[woaimi]

Re: Help to identify a blown cap

here it is guys, please advice. Thanks

[PeteS in CA]

Re: Help to identify a blown cap

Were there any fragments of the device inside the case? SMT tantalum caps are usually in epoxy cases; fragments of SMT MLCCs will look like pieces of ceramic. Whichever it is, it looks like the PCB isn't seriously damaged, maybe not at all. I've seen PCBs ruined by both fried tantalums and MLCCs, so you are fortunate. Also, I don't see a "+" symbol in the silkscreen, which would be normal for a tantalum cap.

[woaimi]

Re: Help to identify a blown cap

Yes, when I first saw it, it was pretty much like ceramic crushed. Is there any way to find out the value for replacement? I have no problem soldering anything, except when it gets too tiny. Thanks again.

[PeteS in CA]

Re: Help to identify a blown cap

Is there any way to find out the value for replacement? I have no problem soldering anything, except when it gets too tiny.

I posted this yesterday:

Unless you have one that is marked with a value (e.g. "103" = .01uF, "224" = .22uF, "105" = 1uF) - not likely - if it's a decoupling cap, I'd figure what the applied DC voltage is, what its size is, and get the largest capacitance in that case with a voltage rating at least double the applied voltage. If it's in a timing circuit (or loop compensation for a VRM), you need to find out what the value should be.

The key questions for you are:

1. Decoupling or timing?

2. Case size (L x W)?

3. Applied voltage?

When you shop for a replacement, stay away from Z5U and Y5V. Those are higher in value for a given case size, but the temperature coefficient is awful - something like +20%/-50%. Use X7R or better.

[kc8adu]

Re: Help to identify a blown cap

assume 25v
iirc the note runs on 19v dc
my best guess in that size might be 1-3 uf.
that wont stop the note from working though.what led up to the failure of the note?

[kc8adu]

Re: Help to identify a blown cap

Tantalum Unless they've changed in the last few years, Sun Microsystems will not use tantalum caps in their products, and require the same of their vendors.

Kemet has a series that is supposed to be less susceptible to sudden failure, http://kemet.com/kemet/web/homepage/kechome.nsf/vapubfilesname/F3102T495.pdf/$file/F3102T495.pdf .

most all tantalum cap failures were the result of some sort of trauma.
reversed supply voltage and overvoltage/spikes are the primary offenders.
problem is they do lots of damage when they go.had a swi prototrak motor from a mill that had a tant flameout in the tach circut.destroyed the wheel and sensor and scorched the wiring badly.took a bit of time and parts to repair that one.customer said lightning struck several blocks away and then a foul odor was detected.

[Rainbow]

Re: Help to identify a blown cap

Once I've bought a really old ISA serial port card (1986). Plugged it in and turned power on. BANG! One of the tantalum caps exploded and caught fire. Turned off the power immediately, flame disappeared. Removed the burnt remains of the cap from the card and it worked fine

[PeteS in CA]

Re: Help to identify a blown cap

Tantalums don't handle surges of ripple current well either. At a previous employer, I had two customer-returns where 50V SMT tantalums fried the PCBs, even though the applied voltage was regulated 28V.

One more suggestion wrt larger form factor SMT MLCCs. If it's practical, install the cap after the MB is in the case, mountings screws tightened. I've seen dozens of MLCC failures that were due to PCB flexure after installation in cases or base-plates. Installing the MB first takes the stress off the new MLCC. Remember that I'm not in your biz, so this suggestion may be laughably impractical.

[woaimi]

Re: Help to identify a blown cap

Thanks everyone for your support. It've been very educationable.
I think power reverse or spike was the cause of this failure. The AC adapter jack on my motherboard broke so I fixed it and immediately after that I experience weird syntom where the power would lit up the light and everything as a working laptop, however when I press the power button to turn it on, the green light immediately turns to amber. I did that few time to investigate the problem, then I found the cap was total destroyed. I getting several value caps according to your suggestion. I'll update with the after match later. I'm also getting a hold of a similar laptop. I'll open it up and see if that help anything. I'm afraid even do ing so wouldn't give me any exact reading of the device.