On 16.03.18 21:23, Joel Roth wrote:
> On Sat, Mar 17, 2018 at 05:05:30PM +1100, terryc wrote:
> > Gak, they are the reliable ones.
> > Everything later only lasts for a few years and you have to buy another
> > round of hardware.
>
> Often hardware is discarded due to failed electrolytic capacitors.

Those which fail quickest are those in switchmode DC-DC converters, i.e.
all computer power supplies today - especially if cheaper electrolytics
whose ESR is not really low enough for long life¹ have been used.

> People don't want to pay a couple hundred for a guy
> who can spot a bulging can and solder in a new one.
>
> I just got an assortment of electrolytics from amazon for
> around $15, 300 pieces!

If intending to use any of them in DC-DC converter, i.e. with high
frequency intermittent current flow with high peaks, it's worthwhile to
check the ESR first. The little transistor and capacitor ESR tester from
Banggood (and probably other ebay suppliers) is dead cheap, easy to assemble
(it's a kit), and easy to use.

That unit also tests capacitance, but if the capacitor is so old and
dried out that capacitance has dropped, then ESR is probably crook too.
(Doubly past its use-by date.)

¹ Each 10°C increase in operating temperature halves lifetime again. (Arrhenius)

Erik