Dave Jones from EEVblog released a video of his investigation into x class safety film capacitor failures.

In this practical case he managed home-made teardown and invite Ron Demcko, KYOCERA-AVX capacitor expert for explanation of the failure type observed.

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You might think you know how film capacitors fail and degrade in capacitance over time – self-healing due to surges, right? WRONG! Capacitor expert and KYOCERA-AVX Fellow Ron Demcko confirms what’s really going on after a teardown of some failed and one good polypropylene X class safety capacitor.

00:00 – Teardown of a some failed film capacitors
00:52 – Self Healing and drop in capacitance
01:44 – Capacitance Measurements
02:15 – Teardown of a new Suntan brand polypropylene X2 film capacitor
03:03 – Different failure modes based on size and winding pressure
05:52 – Unwrapping the film
07:51 – The film inside a NEW film capacitor
09:19 – Teardown of the FAILED uTx brand heater capacitor with half capacitance
10:06 – How Schoopage and the end pin terminations work
12:23 – Teardown continues…
12:45 – WOW! What on earth is this?
14:54 – Elecami Wolf also did a teardown
16:05 – Teardown continues…
17:01 – Separating the film showing both slef-healing and extensive metal film corrosion
18:29 – Another uTx brand failed film capacitor from a Corsair PSU, with 90% loss in capacitance! Elecami Wolf Youtube Channel: https://www.youtube.com/c/ElecamiWolf
19:55 – Let’s call an expert! Ron Demcko from KYOCERA-AVX tells us the REAL REASON for the failure! It’s moisture ingress and corona demetallization!