Aishi capacitor quality

[Pentium4]

I'm curious to know if these caps are quality or not...Can't find much about them. They seem to be fairly uncommon. I have some in a Huntkey unit here and if I ever decide to recap it, I'm wondering if I should leave the Aishi caps or not. All of the ones in this PSU seem to be non critical (4.7uF 50V, 10uF 50V) but then again I've seen a lot of non Japanese little caps that dry out and die.

Anyone here had much experience with them?

[LLLlllou]

Re: Aishi capacitor quality

I've only run into them in the primary of really cheap compact florescent ballasts. Caps have always been fine, but the florecent tubes keep blowing with very few hours on them. Never ran into them in anything else.

[c_hegge]

Re: Aishi capacitor quality

I've seen a few of them used as the secondary caps in Delta PSUs, but anything lasts forever there.

[Wester547]

Re: Aishi capacitor quality

I've seen a few of them used as the secondary caps in Delta PSUs, but anything lasts forever there.

Not always. CapXon are bad enough to fail eventually even in Delta power supplies (I believe CapXon has gone down in quality over the past few years - the amount of failures from them is flabbergasting... they are clearly built to fail), and I think a few Delta power supplies with Ltec failures (the LTG series at least, for which there is no datasheet) have been reported here. I believe even a Taicon startup capacitor was reported to have failed in another Delta unit as well. Of course, the capacitors that did fail weren't in the most ideal quandaries - sometimes a forest of wires were covering them in PSUs with 120mm fans mounted on the bottom, or sometimes their tops were literally touching finless heatsinks in printer power supplies without fans. Or, as you've observed, sometimes the +5VSB diode is touching that particular output filtering capacitor and it leads to discoloration on the PCB. Delta (and Newton) power supplies are well designed, though (well, the lowest end ones do seem kind of cheap even for a Delta, but then they are made for the lowest bidder and how good a power supply is often depends on who the OEM is contracted to build for), for whatever reason - very good airflow, well designed transformers, a hugely overspec'd secondary, etc, but that doesn't mean bad capacitors are immune to failure in them, it just means that they take longer to fail.

That being said, Taiwanese capacitors are too inconsistent quality wise to form a definitive opinion about them. Okay, maybe that's being generous on my part, they do have serious problems and are junk in comparison to Japanese capacitors, but how "good" they (Taiwanese brands) are really depends on their application. Sometimes they last at least a while, sometimes they don't. They are at least a step up from the noname Chinese brands that lie about the capacitor specifications and bloat on their own (maybe with the exception of Arcon, Lelon, GSC, Fuhjyyu, CapXon, etc - the REALLY bad Taiwan brands). What can be said about Taiwanese capacitors though is that they will not last on a motherboard. There's simply too much ripple current and heat passing through them in the CPU Vcore (VRM output/low, which is why that area needs very low ESR capacitors or polymers) or even VRM High (VRM input) section, and they will also fail in other heat prone areas (around the RAM, around add-in cards, around MOSFETs and coils, as well as linear regulators, around the north and south bridge, etc). It's also harder to direct good airflow to them, whereas they are in closer proximity to the fan in a power supply and might even get better ventilation that way.

On topic, I think Aishi make good capacitors. Haven't seen one failed as an APFC primary capacitor or two, or anywhere else for that matter. That said, I think Aishi is a Chinese company (probably the best brand of Chinese capacitors) so that's no guarantee as to their quality either. As for the little capacitors that dry up - in forward converter designs at least, I believe that most of the very small capacitors are used for coupling and decoupling, which doesn't put much stress on them at all. The startup capacitors (often a single 47uF or 100uF, 25V-50V capacitor by the primary side, at least in non-APFC PSUs) are stressed, however, so those should always be recapped.

[Pentium4]

Re: Aishi capacitor quality

Thank you for the replies! I think I will leave them then....It's a two transistor forward design, it's actually fairly efficient.

Yes, I will never pass up an opportunity to rag on CapXon. They truly are garbage and even seen them die in a ton of Delta. Even in a Delta, honestly WHY would you put CapXon on the 5VSB rail?! It's amazing that they last anywhere in any application...Although I will admit to using them on the primary of PSU's with no PFC. I've even seen 10uF CapXon go bad, in multiple situations.

I agree that Taiwanese caps have no business on the VRM of a motherboard, those caps are indeed stressed pretty hard.

[ben7]

Re: Aishi capacitor quality

I think they are good.

Seen one fail in a CFL ballast, but that was because of too much ripple from being powered by a dimmer xD

[kc8adu]

Re: Aishi capacitor quality

had several cheap cfl's go dim/strobing after only a month.aishi caps very high esr.
replaced them for the hell of it and the cfl's are still running.

[Pentium4]

Re: Aishi capacitor quality

They seem to do horrible in those CFL's
What are the specs of them? low capacitance, high voltage?

[RJARRRPCGP]

Re: Aishi capacitor quality

Was GSC even Taiwanese?

[Wester547]

Re: Aishi capacitor quality

To my knowledge, GSC = Sacon = Evercon.

By this link, there may be factories in both Taiwan and China:

http://web.archive.org/web/200905130...about%20me.htm

[kc8adu]

Re: Aishi capacitor quality

4.7@400

they seem to do horrible in those cfl's
what are the specs of them? Low capacitance, high voltage?