STe motherboard axial- and reset-capacitor replacements

[Steve]

@Pacman As long as you buy good brands, they're gonna be fine. Panasonic, Nichicon, Rubycon etc. Just get that Vishay for the 4700uf because it's the only Axial of that size.

If you really want low ESR it really isn't so hard, I use Mouser, the website lets you bring up a list of caps / brands and then you can even sort by ESR. They even have a category in their filter list for low ESR caps .. so to be honest, it's not like it's difficult to find low ESR variants in the first place. Just do that.

[exxos]

Just a word of caution here about brands.. While known brands are generally good, you cant assume the caps are good. I've seen some top brands produce some right garbage caps. For a hypothetical example as I don't remember offhand, Like a 4,700uf cap might have a 3,000mA ESR rating from one top brand. But another top brand might only have 100mA. Shocking isn't it..

I've talked about all this before. Like with Panasonic , they are generally the best for typical 1,000uf caps. But their smaller ranges are not the best and rubycon might be much better. So if you want the best caps for a variety of ranges, your going to have to look at multiple brands.

Of course if the circuit is low current, then ESR probably isn't going to matter that much. Really this stuff should be tried and tested like I did with PSUs. But anyway, generally if a manufacturer doesn't even list ESR, at any test frequency, I avoid them as you just known they will be bad. I've seen new caps with worse ratings than 40 year old caps. Yes, things can be that bad. So it's always important to check the data sheets to see what your actually fitting.

I posted a lot about ESR here viewtopic.php?p=74199#p74199

EDIT:

Some exceptions to "not needing" low ESR caps, IE, low current circuits, can be audio coupling capacitors. Bad ESR caps cause hiss in audio circuits. Even though they generaly have 22k in series with them, you would assume it doesn't matter.But it does. I stopped using electrolytics totally in audio circuits some 20 years ago. Tech has improved of course, but of course caps degrade over time, so I just avoid them as a rule now. It's why you don't see any electrolytics on the H5 etc.

So my thoughts are, if anyone is going to the trouble of buying caps anyway, then why not look at a few brands of caps and get something good.

EDIT2
IIRC, the maximum run time hours for caps is at its maximum ratings. Higher hours is better, but I don't generally look at such things. Exceptions are like on PSUs where the caps might be subjected to heat from heatsinks which can contribute to lowering the life of caps.

In my old job, we just used the 105deg caps as a rule. We dealt with a LOT of equipment. A tiny bit of heat over enough time builds up leading to equipment failing in under 6months.

[Pacman]

I've talked about all this before. Like with Panasonic , they are generally the best for typical 1,000uf caps. But their smaller ranges are not the best and rubycon might be much better. So if you want the best caps for a variety of ranges, your going to have to look at multiple brands.

Good to know!
Maybe someone has created a "recommended caps" list, which would be very useful.

Of course if the circuit is low current, then ESR probably isn't going to matter that much.

The choice of capacitors seems complicated for us non-educated hobbyists, and even buying well known branded capacitors has its challenges
If I'm not mistaken for what you and others here are saying: "don't worry about ESR values" (electronic circuits in general) with the exception of power supply capacitor replacements where it gets even more complicated?

Some exceptions to "not needing" low ESR caps, IE, low current circuits, can be audio coupling capacitors. Bad ESR caps cause hiss in audio circuits. Even though they generaly have 22k in series with them, you would assume it doesn't matter.But it does. I stopped using electrolytics totally in audio circuits some 20 years ago. Tech has improved of course, but of course caps degrade over time, so I just avoid them as a rule now. It's why you don't see any electrolytics on the H5 etc.

That's good to know (I'm also working on some audio projects).
Some of my audio circuits are using tantalum capacitors, and from what I've heard they can explode badly and people recommend replacing them with electrolytics. Catch 22!
Are tantalums of today better/safer than those in the past, so a new tantalum is still better than an electrolytic replacement for audio?

So my thoughts are, if anyone is going to the trouble of buying caps anyway, then why not look at a few brands of caps and get something good.

Agreed!

[exxos]

The choice of capacitors seems complicated for us non-educated hobbyists, and even buying well known branded capacitors has its challenges
If I'm not mistaken for what you and others here are saying: "don't worry about ESR values" (electronic circuits in general) with the exception of power supply capacitor replacements where it gets even more complicated?

It is difficult to generalise such things because every circuit is different with different requirements. Of course if I was building a 555 timer circuit to flash some LEDs, I doubt anyone would really care what the quality of the capacitor is. Though if I put such a thing into production and I wanted it to last as long as possible, then I may spend a little time in choosing a better quality capacitor.

What I suggest is, if you're going to the trouble of looking for a capacitor, you might as well spend a little extra time in looking for one which has a genuine (or best) specification as they are generally much better quality. You generally have to look at datasheets to confirm physical sizes and voltages etc anyway. If they don't mention mA rating then I would just simply avoid that manufacture. If they quote such things, they are generally better than most. Choosing "the best" can take more time. We are not specifically worrying about the ESR as such, we are just being more selective in choosing a part which has proper information listed. If manufacturers don't list information then generally those capacitors are simply garbage should be avoided.

Power supplies and high current circuits generally work better with lower ESR values. A lot of people just go for the cheapest value "which fits" and this can be bad on poor quality caps. You have to imagine a resistor in series with the capacitor. The higher that resistor value, the hotter it gets, and of course heat degrades the life of components. That wasted heat could be better used for improving efficiency and regulation of power supplies and other circuits. If that resistance is too high in whatever circuit it is being used in, it can lead to overheating and they can even explode. I know for a fact some people have been recapping power supplies and selling them with bad quality caps and they have indeed exploded.

It would be like buying a car without enquiring what the MPG is, or the manufacturer simply not listing it. If you don't care about MPG, then everything is probably "fine". A lot of people love to live life in ignorance. But if you do enquire about MPG, and one manufacturer lists 5MPG and the others are all around 40MPG ( assuming the claims are legitimate) then you would naturally go for a 40MPG car.

Some of my audio circuits are using tantalum capacitors, and from what I've heard they can explode badly and people recommend replacing them with electrolytics. Catch 22!

That is probably older advice.

Are tantalums of today better/safer than those in the past, so a new tantalum is still better than an electrolytic replacement for audio?

I haven't tested tantalums for around 20 years. They seem to be "all the rage" back then. I tried one in a power supply circuit once and it exploded. I tried a second one and it also exploded. I wondered if I had it in backwards, so I tried a third one the opposite polarity and that one exploded. I just simply never use them again. I do know a lot of other people have said they have caught fire and exploded and I have personally seen this happen a lot of equipment I have worked on over the years. But I don't really see a need for them anymore anyway.

Audio circuits generally use low values like 22uF. There's a huge range of ceramics which can do that job these days. Of course you need the electrolytic's for the bulk power supply capacitance anyway. But there is certainly no reason to use electrolytics in the audio path anymore.

Of course a lot of my own personal preference is to use better quality parts. Having come from a large company repairing equipment, with manufactures using the cheapest parts, it resulted in a phenomenal amount of repair work over the years. So of course I'm going to be a little bit more biased than people are in general. It's just become a habit for me to chose something better than just "any old part" and calling it job done.