computer power supplies..

I used to own several ST-506s & ST-412s. Long gone now, of course.

I still have a few Seagate 9GB 5.25" FH SCSI drives in external boxes for my old AVID capture setups. I keep them around because they still work and are OEM to the systems.

The problem I see with most PS supplies are cheap parts that fail when the fans cooling them get clogged up with cig smoke or pet hair, dust, etc. That and buying one that is too small for the load you are applying.

How did DELL and eMachines get away with small 250W max rated supplies in P4 3Ghz+ and Athlon 64 3000+ systems? if you added a decent gaming video card and an extra HD you probably had voltage issues.

Hi!

Dell underrates their power supplies *greatly*. I've never had a problem with one, and they seem to be pretty well made, in line with other quality brands.

As an example, the 305-watt rated unit (made by Lite-On) in my Dimension 8300 is powering two hard drives, 2GB of installed RAM, an ATI Radeon X1350, two optical drives, floppy drive and a full host of PCI expansion cards. It has no problems, and has been doing that since it was new. The air coming out of it is moderately warm.

At first it powered a 3.4GHz P4 Prescott which ran distributed.net around the clock. Later, I switched to a 2.8GHz Northwood as the Prescott was good only for putting out heat sufficient to warm a small country.

The eMachines supplies have two things working against them--the first being that in some cases they don't have working overvoltage protection in place. This results in motherboards getting fried. I haven't seen too many that I could say failed as result of running out of capacity anyway.

And you could do worse, with a supply that lies about its capabilities:

William

Hard disks last a very long time if you're careful to give them enough airflow to stay cool.

Ayup.

But most people don't do that.

I have to add "Me Too" I have a genuine Apple ST405 from 1982. Four platter linear actuator. I don't remember how big it was, 10Mb maybe !

I agree. Pay cheap, Get cheap !

I'm sure that was quite deliberate ! Remember the "Warranty Void" if you opened the case. Often enforced by a sticker over the removable case panels. Huge numbers of people caused damage by fitting extra drives, video cards and CD/DVD burners without understanding what they were doing. Like everything else today... Pared down to the bone to cut costs !

Learn what engineers know and what many computer assemblers don't grasp. That 250 watt supply in a Dell is also called 360 watts when sold to computer assemblers. Neither lied. Only one is providing a more honest number. Latter is selling to A+ Certified Computer techs who need not even know how electricity works to be certified.

Lack of technical knowledge is why so many power supply myths are believed by a majority. Other popular myths involve thermal compound, hardware damage due to heat, protectors, and shotgunning. Myths traceable to untrained computer assemblers. So many as to suggest why so much electronic and computer design must go overseas AND why so many engineers (probably a majority) in the Silicon Valley are now immigrants.

A choice is offered. To know only because the majority promote that myth. Or to know by also learning why =96 which means numbers and the underlying reasons why.

Dell does not underrate their supplies. Overrated is technical knowledge of people who never first learned basic electrical principles and then post as if knowledgeable. That has even created a market ripe with power supplies that are missing essential functions. They are selling to the electrically naive. But then this should be obvious. If he does not provide the many technical reasons why - and numbers - then assume myths.

Unfortunately we had Micropolis 9 GB drives for Lightworks that had a fatal manufacturing error that consigned them all to scrap after a year or two.

I have one ancient PC ( my old DOS box ) I've replaced the fan in twice. Bearing failure, nothing else.

Probably because they are *real* watts. The Asian ones are somewhat optimistic.

Graham

- F/H 5 1/4".

Graham

On Sat, 25 Apr 2009 08:17:18 -0700 (PDT), "William R. Walsh" put finger to keyboard and composed:

I have a fake ATX PSU labelled as 400W, yet the Schottky rectifiers on the secondary side can only deliver 200W max. Although it's still working, I replaced it because the +5V and +12V rails were moving about too much during load changes, eg when my CPU cooler program kicked in.

- Franc Zabkar

Westom = troll. Please ignore the patronising ramblings of this idiot.

Thanks. Its a real dinosaur by todays standards. :-)

If the technicals were wrong, the poster would have challenged the facts. Those who cannot attack the messenger. IOW Adrian is declaring he does not have sufficient knowledge to disagree.

A 250 watt Dell supply may be sold to the technically naive as a 360 watts supply. Neither number is wrong. Others who also have this rumored 'underrated' supply aslo had no power problems. Only the naive would post without technical facts. And that is only when I start posting - the challenge the technically naive to demonstrate 'why' they know. Adrian could not probably for good (under educated) reason - an insult he earned by replying without facts and numbers.

to test them i use a PC/SPS TESTER just plug the 20/24 pin connecter in and plug in the power, leds idicate health of supply.

Tester can identify a defective supply. But it obviously cannot report a good supply. Ciritical to testing a supply are voltage numbers when supply is under maximum load. Tester can provide that load and provides no numbers.