ATX Power Supply: I think they forgot something? - Page 1
Forum section: electronics / general

author: jamesp15
author_rank: Regular Contributor
timestamp: December 23, 2012, 05:57:41 pm
content: Came "free" with a Computer case, I can see why.Weighs in at a "hefty" 572 grams. 400watt my ass.How long do you think this would actually work under any kind of real load?(for those interested, its an "Apower" branded "AGS Series 400watt".26a on 3.3v rail, 35a on 5v rail, 12a and 20a on the "2" 12v rails.The wires have 20AWG stamped on them, but they arent even that large.

author: SeanB
author_rank: Super Contributor
timestamp: December 23, 2012, 06:12:05 pm
content: At least they left the inrush PTC in, along with the voltage switch.

author: HardBoot
author_rank: Regular Contributor
timestamp: December 23, 2012, 06:22:16 pm
content: Those standing up semis are gonna get nice and toasty under load.

author: mariush
author_rank: Super Contributor
timestamp: December 23, 2012, 06:23:27 pm
content: It will do 250w for short periods of time, but with horrible efficiency and output quality.

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 23, 2012, 06:33:33 pm
content: Looks like there is some thermal grease on some of the components. Makes you wonder, was the heatsink stolen in transit?

author: SeanB
author_rank: Super Contributor
timestamp: December 23, 2012, 06:42:41 pm
content: more likely recycled semiconductors from a scapper, as they are cheaper and worth more as semiconductors over copper value.

author: jamesp15
author_rank: Regular Contributor
timestamp: December 23, 2012, 07:02:53 pm
content: No thermal grease on them, some of the TO220 parts are discolored/dirty/tarnished. It is/was brand new out of a cheap computer case I ordered.I did some quick load tests: (used the electronic load voltage measurements)12v no load: 11.93v12v 1a load: 10.64v12v 5a load: 8.93v12v 10a load: 7.1v and a low pitched whine from the PSU5v no load: 5.10v5v 1a load: 4.66v5v 5a load: 2.81v5v 10a load: 1.29v!didnt bother with the 3.3v.I didnt want to push it any more as the wires were getting pretty warm.About to take the fan out and trash/recycle the rest of it, unless anyone wants to see any particular measurements/etc out of curiousity.

author: SeanB
author_rank: Super Contributor
timestamp: December 23, 2012, 07:13:02 pm
content: I normally keep those toroids as Rf chokes along with the inrush limiter. I check the caps as well as non critical spares. Many a time i take resistors out of scrap boards instead of buying new, especially for experimenting. the wires will be useful as well, especially the drive leads as extensions in cases.

author: McMonster
author_rank: Frequent Contributor
timestamp: December 23, 2012, 07:58:35 pm
content: Quote from: SeanB on December 23, 2012, 07:13:02 pmI do the same. I also take heatsinks (obviously not the case here) if they look nice and I recently got the idea to reuse the case for my next project. Decent board area, lot of space for stacking the boards and mounting a heatsink in front of the fan. Power switch and IEC connector mounted and ready. And people give them away for free.

author: c4757p
author_rank: Super Contributor
timestamp: December 23, 2012, 08:19:59 pm
content: Damn, it can't even push out 1A at 5V? That's just sad.

author: retiredcaps
author_rank: Super Contributor
timestamp: December 23, 2012, 08:35:57 pm
content: Quote from: jamesp15 on December 23, 2012, 05:57:41 pmIf you like these type of threads, over at badcaps.net there is a "the gutless, bloated, and fried power supply hall of shame" with nearly 500 postshttp://www.badcaps.net/forum/showthread.php?t=8490

author: PedroDaGr8
author_rank: Super Contributor
timestamp: December 24, 2012, 12:08:56 am
content: Hahaha, looks like one of the old LC/Deer blow 'em up specials that were common in cheap computer cases in the late-90s early-00s. Even those though had the decency to include heatsinks.According to your testing, this PSU is doubly troublesome for two reasons. One, its clear that it can't make its rated wattage (heck it might not even make enough wattage to run some case fans) Two, it has NO undervoltage shutdown. It just keeps right on trucking.I would love to see OklahomaWolf over at JonnyGuru.com run this through their stress test.. Get some scope shots of the output and efficiency and all that. Maybe you should volunteer it for testing...I would love to see the pure abysmal fail that this PSU offers up.For those that don't know JonnyGuru is highly respected in the computer industry for his power supply tests. Before him, most sites did the whole plug the PSU into a computer.....does it run? great...this PSU is AMAZING! He purchased a huge Sunmoon psu testing station and began testing the real deal wattages and voltage stabilizatio. Additionally, he was the first hardware site to use an o-scope to follow ripple.

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 24, 2012, 09:50:31 am
content: I have taken apart / repaired easily 500 ATX power supplies... probably more.Never, have I seen one without any heat sink at all... WOW... *applauds* new record!400 watts? That thing? How long would it last??? *takes out his lexan sheets* umm... few seconds? LOL

author: amyk
author_rank: Super Contributor
timestamp: December 24, 2012, 11:09:03 am
content: Those primary caps are surprisingly stout... they don't even reach half the case height!With the heatsink in, it'd probably be around 150W.I like how the sticker on the fan still says "QC passed"

author: SeanB
author_rank: Super Contributor
timestamp: December 24, 2012, 11:31:06 am
content: Well, the fan did pass QC, otherwise known as Quing Chen..........

author: ptricks
author_rank: Frequent Contributor
timestamp: December 24, 2012, 01:12:24 pm
content: Heat sink ? We don't need no stinking heat sink !On supplies like this I salvage the torroids , those can get expensive if you have to buy them new.

author: jamesp15
author_rank: Regular Contributor
timestamp: December 24, 2012, 06:10:33 pm
content: I saved the toroids, 2x STPS1545CT, the power switch, fan and IEC plug.The wires I usually keep for hookup wire use, but these were VERY thin conductors (marked as 20 gauge, stripped them in the 24 gauge notch)The rest is in the recycle bin.

author: Hypernova
author_rank: Unknown
timestamp: December 26, 2012, 01:32:48 am
content: Look on the bright side, they didn't stick any lead slabs in there to weigh it down.

author: T4P
author_rank: Super Contributor
timestamp: December 26, 2012, 06:33:02 am
content: Quote from: Hypernova on December 26, 2012, 01:32:48 amOr plaster ...I had one come with a case and its rated 500W but i'm pretty sure it will blow up long before that, haven't checked the innards though

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 26, 2012, 03:06:15 pm
content: Quote from: Hypernova on December 26, 2012, 01:32:48 ameven the better companies do it.

author: SeanB
author_rank: Super Contributor
timestamp: December 26, 2012, 03:53:04 pm
content: Lead costs money........ They would have used recycled building material.

author: tom66
author_rank: Super Contributor
timestamp: December 27, 2012, 12:29:41 am
content: I do not consider Belkin a good company... they mostly rebadge tat from China. Sure it's going to be safe and EMI compliant, but it's overpriced and poorly made.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 27, 2012, 02:46:54 am
content: Speaking of salvaging parts from old switchmode PSUs, does anyone know of a way to dissolve the epoxy/lacquer used on the transformers? I've often wished I could re-use the ferrite cores and coil formers, but it's not possible to recover them with the potting gluing everything together.It doesn't matter if the enamel on the wires goes too, since I talking about discarding the old windings anyway.

author: Chipset
author_rank: Contributor
timestamp: December 27, 2012, 03:40:58 am
content: Quote from: TerraHertz on December 27, 2012, 02:46:54 amWhile I can't say I've ever dissolved the lacquer on a transformer, as far as solvents are concerned; When in doubt, use acetone.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2012, 04:46:05 am
content: MEK works well, it dissolves almost anything aside from PET, PTFE and one or two other plastics. Does a nasty job on PCB's.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 27, 2012, 08:07:03 am
content: Oh good, Methyl Ethyl Ketone, the most scary of all common solvents. Definitely something to try outside.

author: ptricks
author_rank: Frequent Contributor
timestamp: December 27, 2012, 11:24:18 am
content: Unless it is a really expensive transformer core you are better to just buy cores than try to re-wind old ones. A lot of the transformers now use laminated cores and they really suck to have to put back together.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 27, 2012, 12:33:19 pm
content: pticks, are you talking about ferrite cores for switchmode supplies? I don't know what you mean by 'laminated' in that context. While iron core transformers havealwaysbeen laminated, as without the laminations power loss due to eddy currents in the core is untenable.I'd like to be able to salvage ferrite cores and formers, since I have mounds of old switchmode supply PCBs, and now and them a need to do a custom supply. Buying a suitable ferrite core in unit quantities ranges from difficult to impossible. At least with switchmode supplies you can be sure the ferrite used is roughly suitable to the application.

author: ales22
author_rank: Contributor
timestamp: December 27, 2012, 02:46:54 pm
content: You can heat up the whole transformer with hot air gun or better in well regulated owen to around 150C (maybe 200 or more) until the epoxy becomes slightly soft. Raise the transformer's temp slowly and evenly or the ferrite will crack. Then use some pliers to carefully detach ferrite cores and coil. It takes time, require some skill and is not successful everytime.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2012, 04:05:46 pm
content: The toast until well done method doeas always work, though the former will be unusable afterwards, and you will have to clean off the char.

author: ptricks
author_rank: Frequent Contributor
timestamp: December 27, 2012, 10:28:19 pm
content: Quote from: TerraHertz on December 27, 2012, 12:33:19 pmNever say always, There are transformers that consist of blocks of solid iron where the 'I' end piece can be removed with a hammer and a few hits, the bobbins slide off easily, mainly in really old gear . Then there are the cores that replace solid iron with plates of iron or steel bolted together. Next they went to laminated cores same as the solid cores but now glue or varnish replaces the bolts because the bolts had to be kept out of contact with the core. And finally there is the alternating EI core. The alternating EI core are the ones I hate to work with. They alternate E and I plates and can take quite a long time to put together. Having to completely disassemble a transformer to try out a new winding is a major pain, when with the older cores you could easily change out a bobbin in minutes.