Power supply build quality pictorial DISCUSSION

[gonzo0815]

Re: Power supply build quality pictorial DISCUSSION

This is the question, an engineer has to solve. ;-)
But as seen on the Enermax psu`s, if keept cool may be many badcaps will last, but certainly there are brands which will go bad regardless if cool or not.
I think if you want to go cheap take Jamikon or Capxon, i think both are decent for normal operation and in quantity may be chep. In Germany there are e.g Frolyt and Roedstein, in USA may be ELNA which are all in all shure not the best on the market (regarding ESR and like that) but i think at least they are safe on the long run and have a responsible manufakturing philosophi (unlike some Chinese or Taiwanees producer which are laking in knowledge and responsibility too).

Not forget EPCOS and Vishay / Phillips, but i don`t think they are on a budget.

[Engineer]

Re: Power supply build quality pictorial DISCUSSION

Hi,

hehe - now that's the point I'm wondering:
"But as seen on the Enermax psu`s, if keept cool may be many badcaps will last, but certainly there are brands which will go bad regardless if cool or not."
Which are this "bad" brands ... I'm always sceptical ...

As said - I had to buy some caps urgently - those Samwha were what was on hand in the shop - when getting home - I've realized their specs are much better than I expected (but - never heard of the company) ... so here starts the dilema ...

[gonzo0815]

Re: Power supply build quality pictorial DISCUSSION

The realy bad ones are those at least G-Luxon, Taicon, lelon, some like that crapy names.
Then there are such things like teapo, and ost, which may be safe for short term SHo apps and then some -in my opinion good for long therm like Jamikon, or better Samxon.
Those samwa i don`t know, but IMHO there are some guessing here inh some threads about those caps.
In generalll i think if the unit is cool, not mutch ripple current (e.g. smp) then you can choose some normal caps which for shure haven`t have some water in theri elektrolyt. Those caps, as far as i know din`t depend on high quality materiall at all to be reliable. But make shure they aren`t low esr or something. If you have to do some serious applikation, i think you should order from farnell some good (panasonic rubycon) caps or use some ELNA. If the availiable voltages ifits your need you can order from waifong some MCZ, but hose are rated for 2000h@105°C (double the lifetime for each drop of 10°C below 105°c)
All in all, i wouldn`t gave me to mutch grive at all on that topic, if you know what reliability you need it isn`t that dificult to come to a decision. You can`t get assured quality for chap at low quantity orders..

[Shroomie]

Re: Power supply build quality pictorial DISCUSSION

Re: The Hyena kc8adu posted...Man, those are classics! I have a few Austins that are virtually identical, I posted a rather blurry picture before...They're the ultimate supply to make "What PSU?" jokes about. At least yours doesn't contradict its model number...

[Rainbow]

Re: Power supply build quality pictorial DISCUSSION

Looks like most AT PSUs - they're often very simple and "empty" comparing to higher-wattage ATX ones.

[PeteS in CA]

Re: Power supply build quality pictorial DISCUSSION

It's rated for 200W, but it looks like if you ran it at 200W it would quickly glow and then emit a loud noise and an unpleasant smell.

[kc8adu]

Re: Power supply build quality pictorial DISCUSSION

yes it would.
these are in computers in a truss plant.i change them out on sight.
due to lack of maintainence they fill up with sawdust.the caps onthat ones mobo had gotten so hot they burned the sawdust.considering just the servo card for the saw is 10k you would think they would spend a few $ to do the proper maineainence!

[PeteS in CA]

Re: Power supply build quality pictorial DISCUSSION

Re the "Computer Zone 200W", did you remove the heatsinks or something? I would hesitate to use that for 100W. The DEC tape drive P/S OTOH looks suitably substantial for 50W. The 12V O/P inductor, if it's in the bottom left of the pic, is probably just to filter spikes, and the real "O/P inductor" is probably the transformer primary (i.e. a flyback or "ring choke" topology).

[Rainbow]

Re: Power supply build quality pictorial DISCUSSION

I've had Codegen 200W AT PSU that was empty like that.

[hkivan]

Re: Power supply build quality pictorial DISCUSSION

Starfury1 : It seems that one of the rubycon on I/P bulged.
Can u confirm this ?
I am surprised for a non brand PSU to use rubycon on I/P.
Anyways, for a 250W PSU, 2x 330uF is not quite sufficient.
Futher, no EMI filters ? The heatsinks are thin & small.
22a@ +5V, it looks like the PSU should output around 220W rather than 250w.

[gonzo0815]

Re: Power supply build quality pictorial DISCUSSION

The emi filter is there, but no x or y class components are used. Those small ceramic caps are used instead. If one of them blows, the whole case is on live. this unit fails to meet VDE and probably UL insulation requirements.

[starfury1]

Re: Power supply build quality pictorial DISCUSSION

Yep your right its bulged all right.
I was a bit surprised to see them myself, if they are real rubycons but that said as you have said the design is not up to scratch really so bad use of good components will result in an early demise I guess

I pulled this from a PIII system so guess it was a case /psu deal computer shop knock up no brand computer. I did reccommend putting a better SMPSU but they decided on another cheapie
To repairing it don't think I'll bother. junk for spares

[starfury1]

Re: Power supply build quality pictorial DISCUSSION

Hi Gonzo0815

You do bring up a very valid point about "safety concerns and standards "
How something like this gets passed inspection and allowed to be sold?

This is part of the reason why I orginally junked it a year or two ago

I am no expert on the pro's and con's but suspected there should have been a bit more to the input stage, like those two caps.

It now begs the question
was it a one off or are all of this type out there in this state?

Thanks Gonzo0815 for rasing this issue

[gonzo0815]

Re: Power supply build quality pictorial DISCUSSION

Well, i pulled some new powmax 400w psu`s right after i saw it from the case the came with, for exact the same reason. This case was intended for my brother, and there are no GFI.
In any way if those caps are one of the better, may be they will last, but if they getting older they fore shure breake.
x and y types are made from plastic or paper they never fail.

[gonzo0815]

Re: Power supply build quality pictorial DISCUSSION

Those X and y class caps are realy expensive, those ceramic`s are not to mention. I have seen many psu`s without even those caps. And for shure, there aren`t any authorithy which is able and willing to chek any goods for safety. This is only cheked by the paper if ever.
Normaly, the manufakturer or the importer will hold responsible if a device will lead to an accident. But mutch stuff from China is getting in without proper marking like that. And even if the importer is stated, they won`t be in bussiness long before any problems occure. Those unsafe devices are a mather of fast cash, it is not intended as a sustainable business. So i think, most brand named devices will follow the safety guidlines. but of course, have Levicom PSu which has those ceramics too.

[PeteS in CA]

Re: Power supply build quality pictorial DISCUSSION

There is some chance that those ceramics in the Y positions might actually be agency-approved. I've seen ceramic agency-appoved Y-caps from several Asian and European vendors, and from Ceramite, which I think might be owned now by Vishay. The pic isn't very clear, though. Metallized polyester and polypropylene X- and Y-caps can fail: when they arc, the metallization clears from the site, but there is also residual carbon at the site, which is conductive, and with multiple arcs, those conductive areas eventually cause the cap to fry. I don't know what the failure mechanism was, but I've also seen very bad-smelling, very fried Evox-Rifa PME271 impregnated paper X-caps.

That said, agency-approved X- and Y-caps are certainly better than 1 KVDC-rated generic ceramic caps.

[gonzo0815]

Re: Power supply build quality pictorial DISCUSSION

Well, may be it is possible that an ceramic cap will be x or y class profed, but i doubth that this is safe and i never seen a datasheet on that. As far as i know, x caps are allowed to fail, but y caps never. If y caps fail, they should only go open or reduce the capacitance, but they never have to short.
The description of standard is: x class: if a short occures, substantial dammage could occure, but a fuse can prevent it.
Y class: if y a short occure, no fuse will prevent a possibly lethal, hazardous, elektrick shock.

So if you want to place an cap betwen hot and neutral, you can use x1 or x2 caps. If they short, the fuse will blow.

If you want to place an cap across the hot and the safe ground (i mean the yelow -green wire) then you have to use y class isolation. In any way, metallpaper caps are well known and proved over a long time. Ceramic caps in generall are getting realyweak after some time. well may be, no pc stuff will be in operation after that time.

[starfury1]

Re: Power supply build quality pictorial DISCUSSION

Well I'll leave the debate up to you 2 as you both appear to be more knowledgeable then I in this field, with the pros and cons...

Anyway my camera dosn't have macro so can't get a decent close up.

The caps are marked 102 (think thats 1000 pf) with a 2KW possibly V underneath it
(I hate trying to decipher cap values but its part of the job )

If you look at the smpsu I posted now, thats more like what I would have expected to see

BTW I did reduce the photos but if anyone wants the full size resolution let me know

cheers all

[PeteS in CA]

Re: Power supply build quality pictorial DISCUSSION

Well, may be it is possible that an ceramic cap will be x or y class profed, but i doubth that this is safe and i never seen a datasheet on that.

muRata -
Cera-Mite & Roederstein (both owned by Vishay) - http://www.vishay.com/capacitors/ceramic/rfi/
TDK -

Rifa's PME271 series has indeed been around for decades, and Wima's MP3 series has been around for a long time as well - both impregnated paper dielectric.

Those are GP caps, starfury1. Agency-approved caps are virtually covered with the logos of the approving agencies and, more to the point, the rated voltage is shown as an AC voltage.

[PeteS in CA]

Re: Power supply build quality pictorial DISCUSSION

Panasonic -