wrote in message
oups.com...
I measured a new one, Panasonic FK serires 16V 10uf(Low esr), the ESR
reading is 1.4, and the old one are about 10-17(the cap's brand is
unknown)

The good value on the chart is 1.6.

Should i replace them if they are at least 6 times larger than the
value on the chart?

To consider a cap is bad ,How many times the ESR value has to be
larger than the good one ?


Although I've said on many occasions that the Dick Smith meter gives
unambiguous readings, that statement has to be tempered with a degree of
experience. Interpreting ESR readings is a mixture of art and science, and
if you deal with the subject a lot, you will rapidly get a " feel " for bad
caps. As others have said, a lot depends on capacitor type, and where it is
located in the circuit, as to whether its going to cause trouble. Surface
mount electros tend to have a higher ' natural ' reading than their
corresponding-value conventional types, so it's often a good plan to do a
comparison with a known-good similar type.

I use a Dick Smith virtually every day, and the chart on the front is, in
general, a very good guide, but it should be used as just that, not a
definitive good / not good indicator for all cap types. In normal
circumstances, I would consider anything giving a reading of twice or more
the *expected* value, to be at least on its way, if not truly u/s. Other
indicators help with the suspicion of a bad cap. These are -

Its proximity to anything that gets hot

The ripple ( or other 'AC' ) circumstances under which it normally works,
and how hot this causes it to normally run

To some extent, the normal voltage that's across it, compared to its rated
voltage

Arfa