I want to change a capacitor in a motherboard. It is a SMD tantalum capacitor. On its surface, it's written:
686
16K
935
Does anybody know how to read it?
josdanov wrote:
> I want to change a capacitor in a motherboard. It is a SMD tantalum
> capacitor. On its surface, it's written:
> 686
> 16K
> 935
> Does anybody know how to read it?
>
The best thing, would be to find a datasheet for that particular
capacitor type, to verify the marking scheme. While a lot of the
older, thru hole components were easy to read, I find I'm not very
"lucky" reading the surface mount stuff.
If I had to guess, the 686 would be 68 microfarads. The 16
could refer to a 16V voltage rating. The letter K could be
related to the tolerance, or the package size, purely a
guess. Note that in the example datasheet above, the
parameters are quite sloppy, at least with environmental
temperature and soldering cycles.
The third set of numbers could be a lot code. The first two numbers fit
into standard values, which is why I guessed at 68uf and 16V. The
third number doesn't ring any bells, so could be a lot code.
But it is better to track down some datasheets, if you can.
On Thu, 18 Oct 2007 11:25:51 -0400, Paul <nospam@needed.com>
wrote:
>josdanov wrote:
>> I want to change a capacitor in a motherboard. It is a SMD tantalum
>> capacitor. On its surface, it's written:
>> 686
>> 16K
>> 935
>> Does anybody know how to read it?
>>
>
>The best thing, would be to find a datasheet for that particular
>capacitor type, to verify the marking scheme. While a lot of the
>older, thru hole components were easy to read, I find I'm not very
>"lucky" reading the surface mount stuff.
>
>http://www.avxcorp.com/docs/Catalogs/tlj.pdf
>
>If I had to guess, the 686 would be 68 microfarads. The 16
>could refer to a 16V voltage rating. The letter K could be
>related to the tolerance, or the package size, purely a
>guess. Note that in the example datasheet above, the
>parameters are quite sloppy, at least with environmental
>temperature and soldering cycles.
>
>The third set of numbers could be a lot code. The first two numbers fit
>into standard values, which is why I guessed at 68uf and 16V. The
>third number doesn't ring any bells, so could be a lot code.
>
>But it is better to track down some datasheets, if you can.
I second that, looks like 68uF/16V.
These caps don't usually fail though, I wonder why it's
being replaced.
Somewhere on the interweb "kony" typed:
> On Thu, 18 Oct 2007 11:25:51 -0400, Paul <nospam@needed.com>
> wrote:
>
> > josdanov wrote:
> > > I want to change a capacitor in a motherboard. It is a SMD
> > > tantalum capacitor. On its surface, it's written:
> > > 686
> > > 16K
> > > 935
> > > Does anybody know how to read it?
> > >
> >
> > The best thing, would be to find a datasheet for that particular
> > capacitor type, to verify the marking scheme. While a lot of the
> > older, thru hole components were easy to read, I find I'm not very
> > "lucky" reading the surface mount stuff.
> >
> > http://www.avxcorp.com/docs/Catalogs/tlj.pdf
> >
> > If I had to guess, the 686 would be 68 microfarads. The 16
> > could refer to a 16V voltage rating. The letter K could be
> > related to the tolerance, or the package size, purely a
> > guess. Note that in the example datasheet above, the
> > parameters are quite sloppy, at least with environmental
> > temperature and soldering cycles.
> >
> > The third set of numbers could be a lot code. The first two numbers
> > fit into standard values, which is why I guessed at 68uf and 16V.
> > The third number doesn't ring any bells, so could be a lot code.
> >
> > But it is better to track down some datasheets, if you can.
>
>
> I second that, looks like 68uF/16V.
>
> These caps don't usually fail though, I wonder why it's
> being replaced.
~misfit~ wrote:
> Somewhere on the interweb "kony" typed:
> > On Thu, 18 Oct 2007 11:25:51 -0400, Paul <nospam@needed.com>
> > wrote:
> > > josdanov wrote:
> > > > I want to change a capacitor in a motherboard. It is a SMD
> > > > tantalum capacitor. On its surface, it's written:
> > > > 686
> > > > 16K
> > > > 935
> > > > Does anybody know how to read it?
> > > >
> > >
> > > The best thing, would be to find a datasheet for that particular
> > > capacitor type, to verify the marking scheme. While a lot of the
> > > older, thru hole components were easy to read, I find I'm not very
> > > "lucky" reading the surface mount stuff.
> > >
> > > http://www.avxcorp.com/docs/Catalogs/tlj.pdf
> > >
> > > If I had to guess, the 686 would be 68 microfarads. The 16
> > > could refer to a 16V voltage rating. The letter K could be
> > > related to the tolerance, or the package size, purely a
> > > guess. Note that in the example datasheet above, the
> > > parameters are quite sloppy, at least with environmental
> > > temperature and soldering cycles.
> > >
> > > The third set of numbers could be a lot code. The first two numbers
> > > fit into standard values, which is why I guessed at 68uf and 16V.
> > > The third number doesn't ring any bells, so could be a lot code.
> > >
> > > But it is better to track down some datasheets, if you can.
> >
> >
> > I second that, looks like 68uF/16V.
> >
> > These caps don't usually fail though, I wonder why it's
> > being replaced.
>
> I'd guess at mechanical damage.
Your replacement would also need the correct ripple current rating.
Tants go bang if used over ratings. Unless you really need to
replace it I wouldnt bother.
>Your replacement would also need the correct ripple current rating.
>Tants go bang if used over ratings. Unless you really need to
>replace it I wouldnt bother.
>
>...And ESR.
Since the circuit function seemed acceptible with a mere
68uF cap, it's doubtful there's enough ripple that it'd
matter much. On the other hand if this circuit is blowing
up caps already, might be something else wrong that needs
fixed before the cap is replaced.
> >Your replacement would also need the correct ripple current rating.
> >Tants go bang if used over ratings. Unless you really need to
> >replace it I wouldnt bother.
> >
> >...And ESR.
>
> Since the circuit function seemed acceptible with a mere
> 68uF cap, it's doubtful there's enough ripple that it'd
> matter much.
>kony wrote:
>> On 19 Oct 2007 09:15:42 -0700, meow2222@care2.com wrote:
>
>> >Your replacement would also need the correct ripple current rating.
>> >Tants go bang if used over ratings. Unless you really need to
>> >replace it I wouldnt bother.
>> >
>> >...And ESR.
>>
>> Since the circuit function seemed acceptible with a mere
>> 68uF cap, it's doubtful there's enough ripple that it'd
>> matter much.
>
>Industry experience with tants may say otherwise.
Given the millions of motherboards out there, show us some
that have failed tants?
kony wrote:
> On Sun, 21 Oct 2007 08:41:40 -0700, meow2222@care2.com
> wrote:
> >kony wrote:
> >> On 19 Oct 2007 09:15:42 -0700, meow2222@care2.com wrote:
> >> >Your replacement would also need the correct ripple current rating.
> >> >Tants go bang if used over ratings. Unless you really need to
> >> >replace it I wouldnt bother.
> >> >
> >> >...And ESR.
> >>
> >> Since the circuit function seemed acceptible with a mere
> >> 68uF cap, it's doubtful there's enough ripple that it'd
> >> matter much.
> >
> >Industry experience with tants may say otherwise.
>
>
> Given the millions of motherboards out there, show us some
> that have failed tants?
I'm not saying mobos come with failed tants, I'm saying tants have
ESR ratings and exceeding them does cause failures. These
failures occur in the design stage, not on end user goods. However
if end user replaces tants, failures are likely. Small decoupling
caps on high current lines are where tants are at their most
vulnerable.
Motherboard-SMD Capacitor replacement 
Linear Mode
