Hitachi Mains Cap?

[jayjr1105]

I just bought a new power supply and I've never seen this brand before.

I know the Primary filter cap quality isn't super important in a switching PSU but was just curious.

[mariushm]

Re: Hitachi Mains Cap?

Seasonic uses them a lot, and I don't see any complaints.

[PeteS in CA]

Re: Hitachi Mains Cap?

I've seen Hitachi 450V caps quite a bit, including in server PSUs. They seem fine.

[jayjr1105]

Re: Hitachi Mains Cap?

Thanks guys. Wasn't overly concerned but I've opened up a few PSU units and never saw a blue mains cap.

[budm]

Re: Hitachi Mains Cap?

http://www.hitachi-chem.co.jp/englis...itors/003.html

[jayjr1105]

Re: Hitachi Mains Cap?

4000 Hours seems low for a "japanese" cap doesn't it?

[PeteS in CA]

Re: Hitachi Mains Cap?

Different series have different life ratings. Keep in mind that the rating is for operation at max temperature, ripple current and applied voltage. If the real temperature and ripple current are lower, the expected life will be much greater.

[momaka]

Re: Hitachi Mains Cap?

I know the Primary filter cap quality isn't super important in a switching PSU but was just curious.

Not anymore. All these "new" Active PFC PSUs tend to stress the primary caps a lot more. So having Japanese caps in there matters.

Even more important is how the APFC circuit of the PSU is designed. I'm not sure if this is a coincidence or actual link, but in the last several APFC PSU repairs I did with blown APFC stages, it seems that the primary caps went bad because they weren't rated for a high enough voltage (typically only 400V), probably for the manufacturer to save money. What's concerning is that both Japanese and non-Japanese caps were affected.

So I would say that just about any APFC PSU with 400V-rated and/or non-Japanese primary caps is asking for trouble down the road.

As for Hitachi primary caps - they are okay. I don't recall seeing any failure with them.

[kevin!]

Re: Hitachi Mains Cap?

They are very good capacitors, do not worry about their reliability.
Sony also uses hitachi for its PS3.

[bestsystem]

Re: Hitachi Mains Cap?

i never seen a failed primary capacitor, even in taiwanese brands

usually the output caps on DC 12V 5V rail fail first

[R_J]

Re: Hitachi Mains Cap?

i never seen a failed primary capacitor, even in taiwanese brands

usually the output caps on DC 12V 5V rail fail first

Then you haven't repaired many units. I have seen hundreds, The latest was in a HP Brick power supply for an aio computer, the cap was a Rubicon 150µf/400v And it looked ok but the top was not quite flat and measured 115µf and would cause the P.S. to blow the fuse.

[momaka]

Re: Hitachi Mains Cap?

i never seen a failed primary capacitor, even in taiwanese brands

On old PSUs *without* APFC - YES, the primary caps rarely go bad.
But on PSUs with APFC, I've seen plenty of failed primary caps.