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#164990 - 06/16/07 01:32 AM Dangerous PC PSUs  
hardwareguy  Offline
Joined: Jun 2007
Posts: 50
I've been looking through the forums for a while lately and I like what I see. Anyway, I am a EE student at UT Arlington and I like to take stuff apart to figure out how it works or in this case, why it went down in flames!

There have been a LOT of PC switching PSUs that have been just failing to hold rated load, overheating or even shooting out little bits of flaming shrapnel (bits of rectifier) out the back.

Too bad I don't have pics of the unit but here's what I found in a customer PC:

The PSU was labeled as a 450W PSU but only weighed about 2.5 pounds, I've seen 200W units with more substantial construction. The 12V rail said 30A continuous on the label.... the 12V rectifier had an absolute max rating of 15A! Needless to say, it was toasty, well very toasty, it had a nice chunk missing!

The 3V and 3.3V rectifiers were also similarly undersized but not toasty. The installed rectifiers were in TO220 packages... the correct one would have been in a much larger TO247 package.

No EMI/RFI filter was present at all, not even a cap. This explains why my radio reception went out the window when I turned the ailing PC on.

To add insult to injury, the line fuse was missing!!! On the PCB was a notice: RISK OF FIRE: Replace with same type and rating of fuse. The fuse holder was not present, what was present was jumper wire. This was not a DIY thing, all the soldering was factory! Yikes....

Other sins: 20AWG wire where 18 or even 16 would be called for, counterfeit capacitors, and a sleeve bearing fan.

So how did I find out all of this? Well, this PC came into the shop for a spontaneous reboot complaint (this is 90% PSU or capacitor plague related). I opened the case and saw the Powmax PSU and knew what was wrong but just to make sure, I decided to do a test with a multimeter. Well, when I fired it up, it decided to die right there. The rectifier shorted, the PSU overload protection circuit (switching transistor drive kill) was out to lunch and the smoke poured out. A trace on the PCB burned and cut the power.

The customer is extremely lucky the entire PC was not fried, the thing had a crowbar circuit that worked! The computer itself was put together by a now defunct PC shop in town that was infamous for using shoddy goods. I have fixed many of their POS rigs, I had been stealing their customers for a few years and so did every other honest shop until they folded.

I'll see if I can find the pics I took of a similar, but not quite as bad unit that failed in a friends computer. Somewhere I have pics of a Raidmax "420W" in contrast to the 400W Fortron unit in my PC. The difference is astounding.

Here is a PARTIAL list of known trash PSU makers:
Deer Computer (A.K.A Allied, Austin, Premier, L&C, etc)
Young Year (Aspire/Apevia, older Ultra units)

Most trashy PSUs have at least a fuse, but many leave off the EMI/RFI filter and all of the ones on the list are grossly over rated pieces of Chinese junk. They are the Zinsco of the computer world.

What is sad is I know some class mates that STILL buy them for their own PCs. Oh well, school can't teach you everything. An ounce of experience and common sense is worth quite a bit more than a pound of theory. The EE professor almost had a stroke when he saw a similar board, the Physics prof had no clue why it was all wrong except for the missing fuse! :P

The FTC and CPSC need to step in on this, the BS has gone on too long. These units could cause a fire, at the very least they could (and have!) destroy a computer and the data within.

Arc Flash PPE Clothing, LOTO & Insulated Tools

#165002 - 06/16/07 12:21 PM Re: Dangerous PC PSUs [Re: hardwareguy]  
renosteinke  Offline
Cat Servant
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
This is exactly the reason UL exists. The specific purpose of their standards -testing for public safety- is served by their testing products for these hazards.

If the products you describe are UL listed, the folks at UL would be very interested in any documentation / examples you might have.

If the products are not UL listed.. well, you save a buck or two. Your choice, your risk.

If the UL label is a fraud, again, UL would love to see it.

Finally, never underestimate the power of the marketplace. I can think of a few automobiles that met every standard, yet are history - because they were flawed. Some were even made by huge firms that "owned" the market. Sure they did.

Finally, have you written the companies involved? Some of them actually do seem to be in the business of selling quality products.

A call for governmental involvement should be the last recourse ... not the first. It has been said that, ultimately, government is expected to do three things: deliver the mail, pave the roads, and secure the borders .... once they do those jobs, THEN maybe we can trust them with another.

#165018 - 06/16/07 03:35 PM Re: Dangerous PC PSUs [Re: renosteinke]  
hardwareguy  Offline
Joined: Jun 2007
Posts: 50
You will never find one of these units in a name brand PC, ever. This is a PC shop and DIY thing. Most PC shops have become aware of the problem (the one I got for FREE with a case never left my house, I take some pride in what I sell!) I still see them in PCs made by a shop in town that went under a few years ago, and almost always they come back to the customer with a new UL listed, heavy as heck PSU.

I don't think the sample I had from my friend's PC was UL listed I tossed the unit a while ago so I can't check. Of course, that's the first clue that they are junk. The second clue, and one that should give it away immediately is how flimsy the product feels. They weigh about half what a good one would of the same rated output.

As for UL or CSA listings, the product description on says they are listed, however on a few units when you look at the label on the unit itself, no such mark can be found. Rumor has it that the importers of these POS units will send one unit to test and import another.

I have complained to, but they don't care, the Powmax (the worst of the brands by far) units sell like hotcakes to idiots that measure quality based on how flashy something looks or how good of a "bargain" it is. Newegg is owned by and something tells me they aren't going to consider an email from one person in deciding to suddenly stop carrying a product. Maybe they should look at the reviews, others are not pleased. The ones that are pleased have systems that don't even put a 50% load on these. A PC with one HDD, a DVD drive and a basic Celeron CPU doesn't draw even 200W.

The new ones that are UL listed and DO have a fuse and most of the time, a basic EMI filter (one cap, one choke in hot and neutral), however, they still cannot hold rated load or even close. So they may not burn the house but they are still perfectly capable of taking out a motherboard or CPU. Worst of all, the hard disk usually gets damaged when the things go boom and customers don't usually back up regularly.

As for market forces, they exist on price alone. One of these POS special "550W" units costs about $25, a good 550W unit is around $85-$100. If it's too good to be true, it IS!

Some of the PC shops that used these have gone under due to huge warranty costs and a bad reputation. Now that DIY PC assembly has taken off, these crap PSUs have an even larger market. The average PC DIY with a how to book doesn't know jack about electricity. They don't understand how a PSU with an input rating of 115V @ 2.5A couldn't possibly even come close to putting out 500W. The DIY or uneducated customer is thinking this when I try to explain: conservation of energy? huh? what? Just because they can put a card in a slot doesn't mean they know what they are doing.... kinda like a DIY with a wiring book from Lowes doesn't know how to safely wire his house!

#165026 - 06/16/07 05:20 PM Re: Dangerous PC PSUs [Re: hardwareguy]  
JoeTestingEngr  Offline
Joined: Nov 2005
Posts: 782
Chicago, Il.
This is all very interesting HWG. Perhaps you should post a reference to these findings, and introduce yourself, on the "Computers and the Internet" forum. By the way... WELCOME TO ECN!!!

#165027 - 06/16/07 05:52 PM Re: Dangerous PC PSUs [Re: JoeTestingEngr]  
hardwareguy  Offline
Joined: Jun 2007
Posts: 50
Thanks for the welcome! I will post in the computer section shortly.

Well, I have dug up some more info on the the latest Powmax/Leadman Technologies PSUs.

They claim UL and TUV certification but on the unit I cannot find the UL Registered Component mark (heck I cant even find the normal mark!) nor can I find the TUV mark. I did find the D Mark which is provided by UL-Demko but I have reason to believe that this is bogus.... Europe is even more anal about stuff than the US.

It also claims CE but the the logo is WRONG.

This thing is a fraud, pure and simple and every PSU Powmax has is BS.

With the evidence I have and the customer reviews from, I may fire off another eMail to them. This PSU needs to disappear.

I have a friend that works as a tech at Frys Electronics in Dallas, so maybe he can get me some more data as they are sold there as well. (they NEVER use them in custom builds despite the cost difference...that should tell volumes!)

#165041 - 06/17/07 02:43 AM Re: Dangerous PC PSUs [Re: hardwareguy]  
hardwareguy  Offline
Joined: Jun 2007
Posts: 50
I found something interesting in a friend's junk pile tonight: a CompUSA branded Powmax LP6100D 400W PSU! What is radically different about this older model is the fact that the internals are actually OK! There is a fuse, a good line filter and heavier components throughout. The heat sinks are MUCH larger as is the transformer. It is based on a board that is 99% identical to the newer POS PSUs.

It appears that they got the certification for the old unit, then pulled a fast one and put the POS guts in sometime later.

There is another virtually identical unit with a different model that comes in cases and it has no UL mark. The only difference between the LP6100D and the one that comes with the case is the case version has a single 80mm fan instead of a dual fan and the wattage rating is higher.... 450W supposedly! Yeah right!

Last edited by hardwareguy; 06/17/07 02:50 AM.

#165043 - 06/17/07 02:55 AM Re: Dangerous PC PSUs [Re: hardwareguy]  
hardwareguy  Offline
Joined: Jun 2007
Posts: 50
Oh I found the pics that tell the difference between a quality PSU (Fortron Source 400W) and a shoddy unit, a Raidmax 420W. The difference is STUNNING. I understand the mod wants the images on a server, so just tell me where to eMail them.

I will take pics of the old version of the Leadman/Powmax LP6100D and the new one that came with a friend's case. That friend was educated about the PSU before it saw the wall socket...I probably saved the computer!

See the POS for sale:
Note the way the 4 pin 12V CPU connector is wired.... not cool!

Last edited by hardwareguy; 06/17/07 03:04 AM.

#165044 - 06/17/07 03:08 AM Re: Dangerous PC PSUs [Re: hardwareguy]  
hardwareguy  Offline
Joined: Jun 2007
Posts: 50
This is their support page and they supposedly have testing certificates here. I'm not too familiar with the appearance of a legit certificate, so if anyone knows what a legit one looks like, It would be great. I suspect the UL is bogus, a search for the company yields no results on UL's site.

#165067 - 06/17/07 03:56 PM Re: Dangerous PC PSUs [Re: hardwareguy]  
renosteinke  Offline
Cat Servant
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
One or two little details about UL labels....

First, there is no requirement that a manufacturer have all of his product carry the UL label. Since UL charges 'per label,' it is not unknown for a manufacturer to offer the same product, either with or without the label. Still, if there is no UL tag ON the product, there is no reason to infer that it's the same as the listed version.

Another fact of commerce is that the actual manufacturer may not want his identity known. For example, it may be preferred that the product carry the name of the vendor, or the distributor. For example, Sears make no products - but try to find the manufacturer's name on any.
In those circumstances, the UL label will have a "File Number" on it, that will allow UL to identify the maker.

#165135 - 06/19/07 04:29 PM Re: Dangerous PC PSUs [Re: renosteinke]  
herrmann  Offline
New Member
Joined: May 2007
Posts: 6
hmmm... just a thought.... would it be possible, that some PSU's are plagiated by chinese facturies?
Here in germany, there are a lot of electronical Products with counterfeited Security signs like CEE etc. and trademarks issued.

I can imagine, that the use of less materials in transformers and heatsinks and leaving out fuses and protection circuits would boost the profit margin decently high... at the cost of the end user for sure frown



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