I also retired from FAA. Maybe the Air Defense Long Range ARSR 4 RADARs ,
BI-6, MODE-S and dozens of other 24/7 sytems, are not "critical systems".
Power supply issues were rare. Some of the most robust supplies I have ever
experienced.
Every ham shack I have ever seen has at least one bad one under the bench.
What destroyed the FAA is fanatical political correctness.
73 Leroy AB7CE
-----Original Message-----
From: Gill via Elecraft
Sent: Thursday, April 16, 2020 8:19 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] Electrolytic Capacitor failure
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
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