Corsair VS650 - I was expecting more damage

[Francesc V.]

I've bought a broken Corsair PSU for having some fixing time........(10€ investment)(in bellow image the capacitor is already changed)




Once connected to the serial bulb, nothing happens. So initial assumption is that at least the fuse is gone.

Once opened for visual inspection........I see the main capacitor blown and I start imagine the worst with the Mosfets and other components.



Taken the PCB out and start analysing I confirm that the 12A Fuse is gone, but nothing more till the diode rectifier (Corsair has put there a double rectifier).

No Termistors blown, no Mosfets or Shotky blown away......



The PSU is up&running just by changing the capacitor and the Fuse....How is that possible?

Don't get me wrong.........superhappy to have repair it with just spare parts, but I was expecting a lot of damage when I saw the main capacitor blown.......

Regards,
Francesc.

[stj]

Re: Corsair VS650 - I was expecting more damage

meter the old cap - maybe it shorted internally

[momaka]

Re: Corsair VS650 - I was expecting more damage

I had the same exact thing happen to a ThermalTake Smart M Series M850W (model SP-850AH3CCB) power supply - main input cap shorted and it blew the fuse. Replaced the fuse and cap and works like nothing ever happened. Here's the thread about it:
https://www.badcaps.net/forum/showthread.php?t=62832

And yes stj, in my case, the main input cap was shorted. It was only a 400V-rated cap, so I suspect when the APFC section starts, it sometimes perhaps over-boosts the voltage and makes the cap "eat" the excess.

For this reason, I don't recommend anything less than caps rated for 420V in PSUs with APFC. If possible to fit, use 450V-rated caps of the same capacitance.

And one thing I've been experimenting with (and have confirmed Delta does it on their server PSUs) is adding a PP (PolyPropylene) film capacitor in parallel with the main input electrolytic. The idea being here that the PP cap will handle all of the high-voltage transients of the APFC circuit and possibly also off-load some of the filtering of the high-frequency ripple current from the input electrolytic cap. Also, in the case where the input electrolytic cap goes open, the PP cap may possibly provide at least enough energy storage to safely off-load the APFC inductor and then make the APFC controller shut down. Otherwise, when the input electrolytic goes open, I've seen the energy dumped from the APFC inductor take out MOSFETs and other silicon. Depending on your luck, that can be very few or very many parts.

[Francesc V.]

Re: Corsair VS650 - I was expecting more damage

meter the old cap - maybe it shorted internally

Not when I've measured it.........40K resistance right now..............I guess it blow away due to voltage............... Whatever, PSU fixed

[RJARRRPCGP]

Re: Corsair VS650 - I was expecting more damage

I wish it usually is that easy!