[sdiy] finding bad caps

[cheater cheater]

in-circuit, high ESR is the only thing that'll let you figure out if a
cap is bad or good. What meter are you using?

Cheers,
D.

On Fri, Jul 16, 2010 at 02:11, Barry Klein <Barry.L.Klein at wdc.com> wrote:
> Curious if any of you guys have suggestions on capacitor testing
> instruments.
> I have used the BK 875A LCR meter, an ESR meter, and a Huntron and am really
> not satisfied that I can use these to find bad electrolytic (or other) caps.
> Right now I am just going through some non-working things in my garage, like
> motherboards and LCD monitors.  I see obviously bad electrolytics pull them,
>
> replace them, and many of these things then worked.  But I take those same
> parts and put them on the various instruments and not much becomes apparent.
> Frustrated, I do some research.  There are a couple "cap analyzer" products
> out there - but I'm thinking they work like my ESR meter.  The ESR meter
> does show some variance, but isn't good enough to find everything.  I then
> read about Sencore cap analyzers...  there have been many different models
> over the years.  They test caps 4 different ways. Seem like maybe they would
> be the best bet as they test at rated voltage for dielectric absorbtion and
> leakage as well as capacitance and esr.  There are so many different models
> I ask if you may know if it makes much difference or even if these have
> proven worthwhile units to have for you.  I have ordered a demo of the cream
> of the crop LC03 for a work-related demo to see if it can determine anything
> worthwhile about MLCC caps - the guys at Sencore didn't really know how
> weird MLCC's can be with DC bias... and had not tested them with the LC03.
> After looking at that I'll look at those bad electrolytics...  but I will
> never spend that kind of money on a cap tester for home...  Maybe you know
> of some old jewel tester with the tuning eye tube that does what I want?
> There is a youtube video of a guy recommending one of these but ebay and
> craigslist come up empty finding one.
> I know many of you just guess the date of caps and replace the older ones
> but I'd really like to nail this if I can.
>
> Barry
>
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