Ktec plugpack with bad CapXon GF

[japlytic]

Today, I opened a Ktec 12V 1A (model KSAFC1200100W1AU) plugpack used for a few years on a set-top box (which draws 0.6A). It was making a buzzing sound under load (I suspected there was a faulty 400V cap) and inside was a bulging 22uF 400V unit (in close proximity to the heatsink) and a bulging 470uF 16V unit straight after the rectifier (the 100uF 25V unit further away from the rectifier before the output inductor, as well as the one after the output inductor was not bulging).
The 400V unit was a CapXon KM Series, while the rest were CapXon GF Series.

As I said elsewhere, a significant amount of buzzing under load could reveal that the input filter capacitor after the mains rectifier has gone bad.

I didn't bother reassembling this unit, because it was very difficult to get apart.

(officially, this is my 500th post! - a milestone)

[japlytic]

Re: Ktec plugpack with bad CapXon GF

I now have a Ktec model KSAFD1200150W1AU, with bulging CapXon KM 400V 33uF.
There are two 330uF 25V CapXon GF Series before the output inductor. The 330uF unit closest to the output rectifier was bulging while the other 330uF unit was not (Both were before the output inductor).
I don't know why the 330uF unit closest to the output rectifier was bulging while the other 330uF was not (there was a zener diode placed between each 330uF unit.

Finally, I appear to be losing faith in Ktec plugpacks...

[stj]

Re: Ktec plugpack with bad CapXon GF

i wouldnt blame any cap for failing in small psu's with bad ventilation - they get cooked!