Corsair CX400 with bad OST RLX capacitors

[rsuga]

A bit off-topic but I just wanted to share my experience with this power supply. I've owned it for almost 10 years now with moderate usage (daily, but no OC). Had to replace the fan and the OST RLX series caps (the blue ones), which failed on me twice (one cap was bloated, the other one was bad but didn't show visual signs).

I read somewhere in the forum that these blue OSTs were crap, and I can confirm I had two failures. Of course I've been using them for a long time, but still...

I replaced the first one with Nippon Chemicon KY series (the only good ones I could find, general purpose but still rather low-ESR), and the second one with a new RLS series I had around (I hope it won't fail at least in a couple of years). Probably not the best recap but it's been working well.

This PS also sports additional OSTs RLSes in the outputs which I preemptively replaced with Rubycon MCZs.

Moderator note: split this discussion off from the original thread here: https://www.badcaps.net/forum/showthread.php?t=49596
Also note this thread might also be relevant: https://www.badcaps.net/forum/showthread.php?t=68294

[PeteS in CA]

Re: Corsair CX400W 5vsb goes into safety loop

Actually, NCC KY series are low impedance, high ripple current parts, probably a good choice. As for the Rubycon MCZ, that might be "too good", and it might not be great in a P/S. If I recall correctly, it's an ultra-low impedance part, and that could affect the stability of the control loop. Also, the water-based electrolytes in ultra-low impedance parts don't do well in hot environments, which the output sides of P/Ss tend to be (hot rectifiers, hot output inductors, and an output harness that impedes airflow).

[Behemot]

Re: Corsair CX400W 5vsb goes into safety loop

I have a feeling that those ostors are ultra-low ESR, Seasonics puts few of them in their OEM units for some reason.

[rsuga]

Re: Corsair CX400W 5vsb goes into safety loop

Actually, NCC KY series are low impedance, high ripple current parts, probably a good choice. As for the Rubycon MCZ, that might be "too good", and it might not be great in a P/S. If I recall correctly, it's an ultra-low impedance part, and that could affect the stability of the control loop. Also, the water-based electrolytes in ultra-low impedance parts don't do well in hot environments, which the output sides of P/Ss tend to be (hot rectifiers, hot output inductors, and an output harness that impedes airflow).

Many thanks for the feedback, I was not aware of these potential issues w/ ultra-low ESR caps in SMPS, and it does make a lot of sense. These RLXs are indeed ultra-low ESRs.

I'll look into removing the MCZs in the upcoming months then. I'll see if I can find KZEs or KZHs around, would those be better replacements? Thanks again.

[sam_sam_sam]

Re: Corsair CX400W 5vsb goes into safety loop

KZE are available but not in all UF values I will use KZE or KY or the automotive type of LXZ and LXY and had no issues using any of these series in switching power supply

[Behemot]

Re: Corsair CX400W 5vsb goes into safety loop

yo ignoring me post for what reason?

[rsuga]

Re: Corsair CX400W 5vsb goes into safety loop

yo ignoring me post for what reason?

In my previous post I replied I confirmed the RLXs were ultra-low esrs, I just didn't quote you as I replying to a previous message.

Appreciate your and Sam's input on this. Thanks again.

[Behemot]

Re: Corsair CX400W 5vsb goes into safety loop

so why exactly yo want to replace anything when its working there in milions of units for over a decade now, FROM THE FAB? if those MCZs don't already have 12 years of use on them, I see no reason to replace anything

[rsuga]

Re: Corsair CX400W 5vsb goes into safety loop

so why exactly yo want to replace anything when its working there in milions of units for over a decade now, FROM THE FAB? if those MCZs don't already have 12 years of use on them, I see no reason to replace anything

If you check my original post above, you'll see the original ones are not MCZs but stock OST RLSes w/ 10+ years which I replaced preemtively (w/ the MCZs) together with the two failed OST RLX caps (the blue ones).

What PeteS in CA conveyed makes a lot of sense (ultra low ESRs where we had low ESRs, water-based electrolytes), so that's why I mentioned I was considering replacing the MCZs again sometime in the future.

Tx.