[sdiy] Old Component Breakdown

[Takuya KATAYAMA]

Hello Harry and the List;

Harry, thank you for giving your comment follows.
And I want to tag my comments.

"85C deg." is about JIS standard's maximum specification of normal grade
capacitor.
As Harry said, life span of capacitor is halfs every 10 degree warmer.
So this grade capacitor has been working in room temperature (15C), life
span is
500 x 2^7 = 500 x 128 = 64000 hour = 2666.7 days = 7 year and 4 month.
Not 10 - 20 years.
But we can buy much better specifications such as 1000 hours at 105C (so
called "computer grade" ), it may works same conditions for over 20years.

And at lower ambient temperature, chemical (electrolytic) capacitors'
life span is limited by its leakage of chemical solutions.
In indutrial linear power supply use, it is recomended that replace once
in 3 years.

========================================================================
Takuya "PATA" Katayama at Muse Music Synthesizer Lab., Japan



paia2720 at hotmail.com wrote:

> Hi Takyua:
>
> <snip>
>
>
>
>> (3) is known such as chemical condenser's life span specification.
>> JIS standard grade of chemical condenser's life span is 500 hours at 85C
>> degree at its rated voltage.
>> The life-end of chemical condenser is its "chemical" solution dry-up.
>
>
> You're going to scare the kids to death...
> 85C is VERY hot... usually found in high ripple current / high ambient
> temperatures that a synth will never see (well... MAYBE if you play
> daytime outdoor concerts in Death Valley often).
>
> Capacitor life increases exponentially (close enough) with decreasing
> temperature... and most synth apps are very low ripple current (except
> switching power supplies, which we loathe...) so life should be
> probably 10-20 years minimum.
>
> I don't 'shotgun' replace electrolytics... I only replace as they
> fail. MOST will never (well...hardly ever...) fail. If it is mission
> critical (like an aging power supply) then change it.
>
> H^) harry
>
>
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