Misbehaving PD9280 - A Bit Long
So, here's a good one. DW and I decide we're going camping Feb 8-11. I have the weekend off (amazing!), DW can clear her calendar that weekend, and the kids have Monday off due to the Family Day holid...
Forum Discussion
Mex
It's typically not the voltage rating of the cap which causes the issue. Most front end switching power supply caps (at least the several dozen converters / HDTV's etc I have had open in the past few years) many are rated at 450Vdc, some 250Vdc. Way higher than the 170 Vdc needed here with our 120Vac mains. My guess the manufacturer sometimes uses the same part for the rest of the world operating at 240Vac mains power. The issue is typically an increase in ESR (Equivalent Series Resistance). As the internal resistance increases so does the internal heat a nasty cycle which always ends up with some sort of failure of the capacitor in question. They tend to exploded into pieces, pop out of the PCB or simply bulge a bit before taking some other part in the circuit along with them to the grave yard.
It's typically not the voltage rating of the cap which causes the issue. Most front end switching power supply caps (at least the several dozen converters / HDTV's etc I have had open in the past few years) many are rated at 450Vdc, some 250Vdc. Way higher than the 170 Vdc needed here with our 120Vac mains. My guess the manufacturer sometimes uses the same part for the rest of the world operating at 240Vac mains power. The issue is typically an increase in ESR (Equivalent Series Resistance). As the internal resistance increases so does the internal heat a nasty cycle which always ends up with some sort of failure of the capacitor in question. They tend to exploded into pieces, pop out of the PCB or simply bulge a bit before taking some other part in the circuit along with them to the grave yard.
