What the heck is it

[wcs-ic]

I goggled this and come up with nothing, oh and by the way I'm new here sorta been a lerker for a while and finally decided to go legit. 

[ignator]

I'm guessing a 2.5 farad capacitor, for ram holdup.  Maybe a few minutes if it's dynamic ram.
What is this used in?

[c4757p]

390µF/2.5V capacitor. From the color of the markings, maybe one of the newer solid electrolyte types, though I can't find anything on the specific series. (My first guess was Panasonic FP series - of course, from the "FP" - but the markings are nothing like what the datasheet shows)

I'm guessing a 2.5 farad capacitor, for ram holdup.  Maybe a few minutes if it's dynamic ram.
What is this used in?

Pretty sure that is not a 2.5F cap. 391/2.5 almost always means 390µF/2.5V.


I wish manufacturers would put their name or logo on SMD caps like they do with the leaded ones...

[wcs-ic]

It is on a Toshiba laptop that wont turn on, I tested it with my esr meter and it comes back leaky but I wasnt sure what it was.

[pspgeek]

I'm almost sure is a cap but the markings could mean many things so not sure about the values.

[c4757p]

It is on a Toshiba laptop that wont turn on, I tested it with my esr meter and it comes back leaky but I wasnt sure what it was.

Leaky? Does your ESR meter actually test leakage? Keep in mind that it is a fairly high capacitance, so it will appear leaky if it hasn't had time to charge up.

Or do you just mean it had high ESR?

[wcs-ic]

tested with a  Atlas ESR70

[wcs-ic]

tested with a  Atlas ESR70

This is what it said

[David_AVD]

Err.... was it actually in-circuit?

[wcs-ic]

Err.... was it actually in-circuit?

Measures the same both in and out

[David_AVD]

Maybe check the capacitor with a multimeter (on Ohms) and see what it reads.

[wcs-ic]

Maybe check the capacitor with a multimeter (on Ohms) and see what it reads.

.715

[Rerouter]

if thats ohms, then very likely its faile dshorted, but leave it a while to charge up and stabalise,

[mariush]

The color and the FP marking would make you think it's a Nichicon / Fujitsu  Functional Polymer capacitor, 390uF 2.5v ... example of datasheet: ftp://helpedia.com/pub/temp/datasheets/capacitors/Nichicon/Polymer/2009fpcap_catalog_s8.pdf

The ESR of these capacitors is super low, 0.01 ohm or less.

The problem I have is that those capacitors have FP on them only if they're through hole, if they're surface mounted they actually have the series code on them ... cs, ck, cg etc

It's not unheard of to have some custom batch of capacitors made, especially if it's a Toshiba, but it could also very well be some polymer / functional polymer made by another company. Though who use that intense red color... i don't know.

But basically, the ESR70 and these cheap esr meters are not accurate enough to determine the ESR of polymer capacitors, these have esr under 10mOhm and the esr meter has 0.01 ohm as the lowest value it reports.

[wcs-ic]

So whats the consensus replace it and if so with what?  Man this is why I hate working on Toshiba stuff.

[wcs-ic]

if thats ohms, then very likely its faile dshorted, but leave it a while to charge up and stabalise,

yep ohms, There are 2 of these one on the board and one off they test the same.

[Neganur]

I'm pretty sure this is a low ESR polymer electrolytic cap (Nichicon?)

http://www.nichicon.co.jp/english/products/pdf/2012fpcap_catalog_all.pdf

Probably no point measuring them in circuit unless you know what the circuit they're in is like. Grab a second soldering iron and pull one off to be sure (use extra solder), they're quite reliable and don't usually die. (or so those motherboard manufacturers claim)

[David_AVD]

You are measuring the capacitor correctly (between the pads) aren't you?

The reason I ask is that I find it hard to believe you have two capacitors that are such a dead short.

[wcs-ic]

yep , I even  removed one flipped it over stuck it is some putty to hold it still and measured it with some needle tips same result. Kinda weird.

[mAJORD]

You are measuring the capacitor correctly (between the pads) aren't you?

The reason I ask is that I find it hard to believe you have two capacitors that are such a dead short.

Not odd if theyre both sitting on a supply rail with a blown ( in_out short) reg.  Probably other stuff dead too if that happened

[wcs-ic]

You are measuring the capacitor correctly (between the pads) aren't you?

The reason I ask is that I find it hard to believe you have two capacitors that are such a dead short.

Not odd if theyre both sitting on a supply rail with a blown ( in_out short) reg.  Probably other stuff dead too if that happened

Kinda what I thought, it's a friends laptop so I was just doing him a favor. All the other caps test good but these 2 are kinda odd and appear more work to find replacements than it's worth not knowing the condition of the other components. If nothing else it got me to join the forums, thanks to all who have put in there 2 cents.

[amyk]

What's the model number of the laptop? It might be possible to find a schematic for troubleshooting.

(I assume the OEM model is not a Quanta MX3, which also has a 390u/2.5V cap at position PC78...)

[wcs-ic]

It is a Satellite L745-S4210 and the 2 caps in question appear to be 390u/2.5V  at positions PC60 and PC78

[David_AVD]

If the caps are shorted, replace them and move on to the next step.

[wcs-ic]

I wasn't sure of there values at first or a good suppler, I have not bought and of this type,  Believe it or not I usually use Amazon