PSU fan stopped...

[Th3_uN1Qu3]

Re: PSU fan stopped...

Don't think you'll find any specs on Jun Fu caps. Or... wait. Thank God for Google Translate. The datasheet shows that worst case ESR is 0.06 ohms, so both of your Jun Fu caps are within spec. Like all cheap brands, they're only rated for 2000 hrs tho.

[retiredcaps]

Re: PSU fan stopped...

In fact I just tested some of the ones I removed:

Used an Atlas ESR70.

I don't have an ESR meter, but I have 2 multimeters that can measure capacitance and with ALL my bulged caps, I get significantly lower uF than what is on the sleeve. I never get a measurement more than what is on the sleeve.

For example, the latest bloated 1000uF 16V KZGs I pulled from a motherboard, they all read between 100uF and 330uF.

If you have a multimeter that can measure capacitance, try these caps on it.

[tom66]

Re: PSU fan stopped...

Thanks for the datasheet, but the vent doesn't match the datasheet specifications. The datasheet shows a vent much like a Mercedes badge, but this one is just a cross. Wonder if they are fake crap caps? That would be strange... Or maybe Jun Fu just rebadge caps...

[Th3_uN1Qu3]

Re: PSU fan stopped...

It depends on the meter, but around here it's common knowledge that if a cap registers significantly higher than it should then it is probably bad (high leakage). As for the vent... i think they just use whatever comes in handy. I have a bunch of (still good) Jun Fu caps pulled from various PSUs, i'll check their vents tomorrow, but IIRC mine have a mercedes type logo indeed. Anyway, we can at least agree that the color in the datasheet matches the caps, so that's probably good enough.

Judging by their site i'd say they manufacture the caps themselves. http://www.junfu.com.tw/

[tom66]

Re: PSU fan stopped...

Tested with a multimeter. Nearly the same results. A few measured about 100uF lower than the ESR70 says which put them barely in spec.

[retiredcaps]

Re: PSU fan stopped...

Tested with a multimeter.

Thanks for testing that. Funny, I just haven't run into that situation and I have a quite a few bloated caps.

[tom66]

Re: PSU fan stopped...

Thanks for testing that. Funny, I just haven't run into that situation and I have a quite a few bloated caps.

Probably both the multimeter and the ESR70 test the same way; perhaps they are susceptible to high leakage?

I just tested a sample; they measured around 8kohm (fixed range), which is awful leakage, and probably means they are completely shot.

[PCBONEZ]

Re: PSU fan stopped...

I highly doubt the LZ's meet the spec as described in the datasheet. I'll take the shotgun approach: replace with very low ESR replacements (Panasonic FC, FM and FR are good, as are Rubycon ZL*.) I don't usually bother to match ESR, but maybe I should?

FC, ZL and ZLH aren't even in the ball park to replace the LZ.
.
Regardless of what you think about LZ meeting their specs...
... When they chose LZ they looked at the LZ data sheet.
... and not the cap itself.

Thus, if you have any common sense, you would use what the LZ data sheet says as to what should be there in that PSU.

It's really not that tough a concept........
.

[PCBONEZ]

Re: PSU fan stopped...

Thanks for the datasheet, but the vent doesn't match the datasheet specifications. The datasheet shows a vent much like a Mercedes badge, but this one is just a cross. Wonder if they are fake crap caps? That would be strange... Or maybe Jun Fu just rebadge caps...

Off beat small companies like Jun Fu don't make their parts, they buy them.
That means their cans will have whatever vent the cans they bought have.
.

[tom66]

Re: PSU fan stopped...

FC, ZL and ZLH aren't even in the ball park to replace the LZ.
.
Regardless of what you think about LZ meeting their specs...
... When they chose LZ they looked at the LZ data sheet.
... and not the cap itself.

Thus, if you have any common sense, you would use what the LZ data sheet says as to what should be there in that PSU.

It's really not that tough a concept........
.

I chose whatever I could get. I'm not going to spend £16 to get some caps, when I can buy another POS power supply for £15 from fleabay. It's stable and the PC still boots (was working as before.) I'm not complaining.

[tom66]

Re: PSU fan stopped...

Off beat small companies like Jun Fu don't make their parts, they buy them.
That means their cans will have whatever vent the cans they bought have.
.

Does this mean their specifications are just an average of their suppliers? I have one Jun Fu 680uF/16V that measures 0.03 ohms, and another that measures 0.06 ohms.

[PCBONEZ]

Re: PSU fan stopped...

No, maybe, depends on what you mean.
I don't mean like they buy caps and rebrand them.
They actually make the caps but they buy at least some of the foil, cans, leads, bungs, and electrolyte from someone else.
The larger companies usually make most of these parts in house. - More consistent product.
The small ones usually outsource at least some of them, if not all.
.
You're measuring -used- caps.
They aren't likely to be the same anymore.
With one at 2x the ESR of the other it looks like one is definitely shot, the other maybe.
.

[tom66]

Re: PSU fan stopped...

I suppose if there's a market for them, companies will fill the void...

You're measuring -used- caps.
They aren't likely to be the same anymore.
One is definitely shot, the other maybe.
.

Can ESR decrease at the end of life of a capacitor?

[PCBONEZ]

Re: PSU fan stopped...

If it fails by shorting it will look like it did.
.
If you suspect a shorted cap check ohms also with a regular DC ohm meter.
If it's low on both -> Shorted or partially shorted cap.
.

[tom66]

Re: PSU fan stopped...

If it fails by shorting it will look like it did.
.
If you suspect a shorted cap check ohms also with a regular DC ohm meter.
If it's low on both -> Shorted or partially shorted cap.
.

The cap meter measured it at 732uF (rated 680uF +/-20%). I didn't check for DC resistance.

The power supply still worked with these bad caps, even when playing a game on a power hungry 9800GT occasionally, but I don't think it would have lasted.