Old power supplys

[The321]

Alot of people always say using old power supplys is a bad idea cuz it can blow up or damage components. But why would this be due to aging as far as i see the capacitors will get less capacitance and your output voltage would be less stable. But why would an old psu blow up if it isnt clogged with dust or anything?

 

 

[DailyProcrastinator]

6 minutes ago, The321 said:

Alot of people always say using old power supplys is a bad idea cuz it can blow up or damage components. But why would this be due to aging as far as i see the capacitors will get less capacitance and your output voltage would be less stable. But why would an old psu blow up if it isnt clogged with dust or anything?

 

 

Cheap/old components can fail, it is as simple as that. Even voltage ripple can kill components, regardless of whether or not the PSU itself does not fail. Also, voltage control is better on new PSU's.

[LukeSavenije]

and even if it's fine, hardware changes

 

and PSUs change with it, you shouldn't pair a old design with new components

[Guest]

12 minutes ago, The321 said:

Alot of people always say using old power supplys is a bad idea cuz it can blow up or damage components. But why would this be due to aging as far as i see the capacitors will get less capacitance and your output voltage would be less stable. But why would an old psu blow up if it isnt clogged with dust or anything?

 

 

I'm not sure why people assume that capacitors are the only thing in a PSU that fail.  But it's a common misconception.  A PSU is not a box full of caps.  Nor do capacitors in PSU tend to fail.

 

If the output caps fail and the ripple increases, that can kill components.  But failing rectification circuits, like from an overworked or overheated MOSFET, can cause a lot of damage if the PSU's protections don't kick in.  Or if the UVP is set to low or the OVP, OCP or OPP is set too high?  And what if the housekeeping IC isn't fully functioning?   You can hope for a complete failure, which would cause the PSU to not power on at all.  But that's not always the case. Some failures may only occur at higher temperatures.

 

This is a fun read:  https://anysilicon.com/best-practices-ic-troubleshooting-ic-failure-analysis/

 

Speaking of higher temperatures.... 

 

The part that typically fails first in a PSU is the fan.  This doesn't always cause a problem immediately, of course.  If you have a high efficiency, high capacity PSU, you may never experience a problem with the PSU running without active cooling.  Say you're using a 1000W Platinum PSU to power a system with a single graphics card that really only uses 550W at the most.  But if you're using a cheaper, lower efficiency PSU that only has just a little bit of overhead above the amount of power needed, lack of active cooling can result in catastrophic failure of other parts.  A "domino effect", so to speak.  Fan fails.... FETs fail....  ICs fail....  Voltages go haywire and kill your parts.

[Stefan Payne]

46 minutes ago, The321 said:

Alot of people always say using old power supplys is a bad idea cuz it can blow up or damage components. But why would this be due to aging as far as i see the capacitors will get less capacitance and your output voltage would be less stable. But why would an old psu blow up if it isnt clogged with dust or anything?

Its a bit more complicated, here we have a couple of different things, for example:

• newer, even really cheap PSU are better than the average 10 year old one. Back in the day, most PSU were crap by todays standards
• Changing in power consumption! Not just move to 12V from 5V (was in the early 200s) but also the way the components consume power. In the last couple of years its changing more towards more peaking current because of Power Saving Mechanisms and the so called "Race to Idle" philosophy. for example when you move the mouse the CPU clocks at higher frequency and changes it constantly and sometimes you hear that in the PSU
• Aging components, for example ripple going high, Protections failing, voltage regulation getting loose and other stuff.

 

The thing is that you do not know how good the PSU is and you don't have the gear how it looks.

 

An example of how older PSU might look is here (Sadly German):

TL;DR:
one of the PSU is around 500mV, the other PSU is around 1V or more

The Specification is around 120mV...

 

Modern PSU are under 60mV (cheaper ones) or the better ones are like half of that.

Voltage Regulation, the shitty ones are at 3% for 12V, the better ones at 1% or lower.

 

14 minutes ago, jonnyGURU said:

I'm not sure why people assume that capacitors are the only thing in a PSU that fail.  But it's a common misconception.  A PSU is not a box full of caps.  Nor do capacitors in PSU tend to fail.

How can you say that???????
Everyone knows that only Capacitors fail!!!1111

14 minutes ago, jonnyGURU said:

 Or if the UVP is set to low or the OVP, OCP or OPP is set too high? 

Or just not there...

As some Protection Chips like the HY-510N I like to mention don't come with UVP on 12V at all and some/many have very low UVP trip points that are almost useless. IIRC some are at like 8,5V or so for 12V. 

 

14 minutes ago, jonnyGURU said:

The part that typically fails first in a PSU is the fan. 

But but you can replace the fan!!11

That is easy!!1111

 

Here a "Guide": FROM 2014!

 

[Stefan Payne]

6 hours ago, campy said:

But if you can find an S12II or something like that for dirt cheap, grab it, its gonna be a decent psu with a 5 year warranty. Just that its not preferable to modern power supplies under normal circumstances.

Why should he?!
 

For the amount of money those things are sold, you can get DC-DC units from some Companys.

ANd I rather have a (new) Corsair VS than S12II because its better.

[Stefan Payne]

3 minutes ago, campy said:

VS series has only a 3 year warranty, lower efficiency,

Irrelevant measures.

3 Years or 5 years don't matter.

Efficiency doesn't matter

 

Voltage regulation does matter

Protection does matter

 

3 minutes ago, campy said:

Theyre really just average PSUs but the S12II's are higher efficiency with a better warranty and about the same price on average.

The S12II is loud as hell, ~2000rpm at 250W load or so.

No Undervoltage on 12V

No overcurrent on any rail

Group regulated

 

3 minutes ago, campy said:

Hence why i say "for dirt cheap" because something like the S12II 520 still goes for 50-60$ which is just too much for what it is, but ive seen em on sale often for 30-40, which is worth the 10 bucks over the VS 550 if it was off rebate.

No, it is not. 

Why the heck do people still recommend the S12II when you can litterally get everywhere a better unit for the same amount of money or a better unit?!

 

Oh wait, you got blinded by Wapanese caps, made in China, wanna be Japanese...

3 minutes ago, campy said:

The EVGA 500B being a similar older unit a little bit more on par with the S12II's

I'd say even the EVGA 500B is superior to the S12II...

 

3 minutes ago, campy said:

Its like, yeah, the S12's are so old they dont even support the haswell power saving features,

...wich is why you do nor recommend it because it gets beaten the shit out of it by many lower end PSU from various manufacturers.

You even can get some DC-DC units from some manufacturers. 

You can get somewhat decent protected PSU from manufacturers.

 

Here more information for you:

 

[Guest]

26 minutes ago, Stefan Payne said:

 

But but you can replace the fan!!11

That is easy!!1111

 

Assuming you realize the fan actually died. 

[Stefan Payne]

2 minutes ago, jonnyGURU said:

Assuming you realize the fan actually died. 

Sorry, forgot to mention that most of the post I quoted you was joking and not honest.

 

I'm not an advocate of replacing the fan for many reasons, including legal ones...

[hello_there_123]

41 minutes ago, campy said:

Id take a 30$ 520w S12II over an evga 500b/vs450/cx450m/any other 500w generic any day simply because of that 5 year warranty and the fact that theyre tried and true power supplies.

Ok, so what if it is "tried and true" aka more well known? What difference does that make? 

 

 

[Spotty]

2 minutes ago, campy said:

VS series has only a 3 year warranty, lower efficiency, and is the same kind of later years FSP guts as every other 80+ white label psu out there.

What do you mean by this? The VS series has the same FSP guts?

 

20 minutes ago, campy said:

Theyre really just average PSUs but the S12II's are higher efficiency with a better warranty and about the same price on average.

They're not the same price though.

Corsair VS450 is currently $39 (without rebate!). It's $24 with the currently available $15 rebate.
Seasonic S12ii is currently $55. That's more than twice as expensive as the VS450 is with the rebate available. Even without the rebates the VS450 is still $16 cheaper. If you're talking about buying cheap, low range PSUs then $16 is a huge difference in price.

https://pcpartpicker.com/product/fZyFf7/seasonic-power-supply-s12ii520bronze
https://pcpartpicker.com/product/6rc48d/corsair-vs-450w-80-certified-atx-power-supply-cp-9020170-na

 

Spoiler

 

 

6 minutes ago, campy said:

Id take a 30$ 520w S12II over an evga 500b/vs450/cx450m/any other 500w generic any day simply because of that 5 year warranty and the fact that theyre tried and true power supplies.

You're saying that the reason you would choose a S12ii over a Corsair CX450m is that the S12ii comes with a 5 year warranty? That doesn't make any sense since the CX450m has a 5 year warranty as well. Not that it really matters. Putting a X year warranty on a unit doesn't make it perform any more reliable than if it had a Y year warranty. Yes, better built PSUs will typically come with longer warranties, but having a longer warranty period doesn't make it a better unit. If Corsair came out tomorrow and said "Hey everyone, we've decided the VS450 has a 5 year warranty now. Anyone who already owns one will be automatically upgraded to the 5 year warranty period" does that make the PSU already sitting in peoples systems magically become better built or more reliable? Of course not.

 

11 minutes ago, campy said:

They also have a really good looking box, not many people care about that, but i like that the box looks nice.

I'll have to keep that in mind for the next time someone asks on the forums for help choosing a PSU that comes in a cardboard box with a nice looking picture on it and doesn't care about the unit inside the box.

[Stefan Payne]

21 hours ago, Spotty said:

Yes, better built PSUs will typically come with longer warranties,

Not necesarily.

 

You can also build a cheap unit that fails regularly after 4 years and calculate with a 10% Failure rate over its lifetime and also formulate the Warranty Terms in a way that they can exclude most PSU.

 

As for the Warranty terms:

Some Manufacturers have a couple of things that allow them to reject the Warranty for certain reasons.

The most common one is the proof of purchase because some people throw it away or loose it and thus no warranty for them.

Another example is Mining exclusions, wich they could also claim.

And Enviromental Damages are also excluded. So if a manufacturer is a bit malicious they remove the coating inside the case where you do not see it (but they know what to look for) and look for rust. Since it is steel, it will rust. But with rust, they can claim enviromental damage.

 

 

And some Manufacturers (like EVGA) Even have a Smoker Rule!
So if you smoke in your PC room, that voids the Warranty.