[Elecraft] Electrolytic Capacitor failure

[EricJ]

They are rarely operated 24/7, and they aren't usually supervised by 
career engineers. Most hams are relatively inexperienced hobbyists who 
may not recognize a problem until it is catastrophic. Someone in this 
thread already mentioned that nearly all ham shacks have a bad 
electrolytic lurking under the bench.

Eric KE6US

On 4/16/2020 7:38 AM, CUTTER DAVID via Elecraft wrote:
> Hello Gill
> Doing reliability calculations to MIL 217 was very instructive many years ago and it taught me that operating well under the limits extended MTBF a lot.  Some military customers instructed that specs were 60% or more degraded to achieve longer service life.  What was your experience of that? It amazes me that amateur psus last so long!  Then, again, they are rarely continuously operated 24/7.
> 73
> David G3UNA/G6CP
>
>> On 16 April 2020 at 15:19 Gill via Elecraft <elecraft at mailman.qth.net> wrote:
>>
>>
>> As Harlan pointed out - I was an engineer for the FAA until retirement -
>> We changed electrolytics as part of normal PM's on critical systems
>> usually every 5 years or so. CDE (Cornell Dubilier) indicates expected
>> life (MTBF) of devices operated within rated voltage & temp specs to be
>> about 80-100 thousand hours. Most failures occur quickly around the end
>> of that period. For 24/7 operated systems, that translates to around
>> 8-10 years before rapid EOL failures begin to occur. Electrolytics can
>> be thought of like incandescent lamps - they have a finite useful life
>> and the fail quickly around the end of that time. ESR (Equivalent Series
>> (AC) resistance) increases which reflects in higher ripple currents in
>> power supplies are a main culprit. Check out:
>> https://www.cde.com/resources/technical-papers/reliability.pdf
>> 73 Gill W4RYW
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to d.cutter at ntlworld.com
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to eric_csuf at hotmail.com
> .