On Fri, 20 May 2011 11:34:42 -0700 (PDT), KenO
wrote:
Am looking for a reliable cost effective ATX Power Supply.
Reliable, powerful, cheap. Pick any two.
While researching found "Who's Who In Power Supplies, 2011: Brands Vs.
Manufacturers"
http://www.tomshardware.com/reviews/...urer,2913.html
Interesting article, but insufficient information to even offer a
recommended power supply.
"Lack of protection circuits, low efficiency, and bad build quality
were major points of criticism." Like most PC hardware seems
important to do your homework.
If you look at the various ATX schematics found by Google Images, you
won't find one that lacks input protection. That's because in order
to obtain the multitude of certifications and logos plastered all over
the serial number sticker, input protection is required.
What I look for is power factor correction. That will drop the
efficiency somewhat, but is well worth it (and will soon be
mandatory).
Hope the protection circuits work. Do not want an explosive or fire
problem so am especially interested in power supplies that have
survived catastrophic events.
The manufacturers warranty only extends to the value of the power
supply. The metal case does quite well at containing any explosions.
However, the clear plastic fans, with plastic grill, will not survive
and probably fragment if the guts explode.
A few years ago, I decided it would be interesting to see what happens
if I load an ATX power supply with it's maximum ratings. The power
specs are a bit complexicated, so I settled on a somewhat less than
maximum load. For example, the 5V and 3.3V loads are combined for a
maximum of 115W. I forgot exactly what I used:
www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf
250 watts of heat is a lot of heat.
I dug out my collection of junk ATX supplies, and fired them up. I
think two of them simply shut down and gave up. One blew up, but it
may have been blown before the test. Most survived for about 5
minutes, and then shut down from overheating. The 5V line dropped to
as low as 4.2V on about half the supplies. The 12V line was even
worse, dropping to below 11VDC. None of the junk power supplies came
even close to meeting their own specifications.
So, who makes high quality ATX power supplies? Well, it's none of the
commodity or OEM vendors. It's possible that the industrial and
server vendors have better power supplies, but I didn't test any of
those. I also can't afford them.
So, how do you pick the lesser evil power supply? Well, one way is to
check the density of the components. If the PCB is sparse, with large
empty gaps between components, they've cut some corners. Better power
components tend to be big and heft. If the power supply is crammed
full of parts, you have a good chance of having found something
usable.
Also, I rather like Dell power supplies. I've had my share of Dell
failures, but reliability is not the attraction. In their larger
boxes, Dell uses a single 120mm cooling fan, with the speed controlled
by the temperature. That makes for a very quiet machine.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#
http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS