Let's play "what part is failing?"

[jaguar]

So go buy a new one , if you have a 250watt get a 300-350watt , the price diff is SMALL !!!!!

There is a reason for that. It's the same thing. The only decent PSU out there are from brands like Antec and TopPower.

[Undertoad]

$23 Sparkle 300W from newegg. They have a good reputation if you want to go "cheap".

[tw]

Originally posted by Undertoad
$23 Sparkle 300W from newegg. They have a good reputation if you want to go "cheap".

A terrible reputation because even specs in that URL say so. Two most critical and essential functions in a power supply - even found 30 years ago - overvoltage and overpower protection. They provide almost no numerical specs and still the power supply is obviously crap.

How do you think they sell a power supply for so far less than $60 retail? They simply forget to include essential functions. Goes right back to a previous thread where I discussed the technical ignorance by so many computer people. The Sparkle supply is dumped into N America at higher profits because so many American technical experts don't even look at specs let alone understand them. It says right there -

Over Voltage Protection: Not specified
Overload Protection: Not specified

They could not have been more blunt. The supply is missing essential functions necesary even to keep power supply from destroying motherboard, disk drive, memory, etc.

[tw]

Originally posted by vsp
Possible, but I'm wondering how I test that. I will note that the power switch behaves perfectly when I do the hold-for-five-seconds-to-kill-the-power thing.

Look at the long list of speculated reasons given. I can probably number the number. And yet most every suggestion would be made redundant in minutes with the 3.5 digit multimeter. You have no numerical facts, some symptoms, and a load of speculation. Get the meter now and don't even waste time. It is that important, even to say if the power switch is sticky or intermittent. You can guess all we want, but without something to see electricity (with numbers), then we all will spend long hours playing witch doctors.

Get the meter. There are three subsystems just in the power supply - the PSU, motherboard control circuit, and power switch. Get the meter so that power supply can be eliminated as defective OR isolate the problem to one of three possible problems. All done in minutes.

BTW, you will also learn how the computer really works.

[tw]

Originally posted by vsp
Thank you, Tony. Now I will NEVER SLEEP AGAIN anywhere where there's a computer in the house. Yeeeeeegh!

Not mentioned is that if the CPU was an Intel, then overheating only slows processor down; no damage. This function has been in all Intel CPUs as far back as the 486DX2-66 ; and maybe even longer.

However if an Athlon runs with heatsink disconnected, then Athlon will be toast within less than 5 seconds and usually also damages motherboard:
Hot Spot - How Modern Processors Cope With Heat Emergencies

Onboard temperature sensor only protects Athlons if heatsink is attached enough that CPU does not overheat quickly.

But this is irrelevant to your problem. In fact, running a system in a 100 degree F room is how one debugs a defective computer. 100 degree F is normal temperature for any properly functioning PC.

[Undertoad]

FWIW I have tested a Sparkle with a multimeter and the voltages were sound, but if you want to pay more you may. Of course a replacement motherboard is $75 these days so an additional $50 for a top class PS is up to you.

I don't keep a 100 degree room personally but there are those who might.

[Undertoad]

my own personal PSU

The blue LEDs are helpful cos they tell you the power supply is on when it's dark and your system is under the desk. But it's $84.

[tw]

Originally posted by Undertoad
FWIW I have tested a Sparkle with a multimeter and the voltages were sound, ...

Only MBA trained management believes one can test for quality. Every defectively designed power supply will provide correct voltages during their lifetime. Those voltage measurements say nothing about supply quality. But then readers of W E Deming's book "Out of Crisis" (last time I looked, it was in its 26th printing) would recognize that voltage measurements are classic symptoms of an organization that had no quality. The point here being that every reader should have immediately recognized that voltage measurements report nothing useful. If it was not that obvious, then concepts of quality have not yet been learned. Concepts of quality are not always so obvious until after they have been learned.

The Sparkle power supply is dumped in America because so many so called computer experts recommend technology they don't even understand.

BTW, that voltage test is the exact same reasoning that sent 7 Challenger astronauts to death. "It worked just fine yesterday - therefore it will launch just fine today." IOW "engineers are only dumb idiots. Thank goodnes we managers are so much smarter."

The Sparkle tech numbers say it is crap. The O' rings on a similar and (one year) previous shuttle launch said quite loudly that Challenger should not be launched. Like the Sparkle recommendation, the shuttle manager 'expert' need not first read the numbers or understand technology principles. He just knows like so many clone computer assemblers who buy crap power supplies on one spec - price.

VSP - I am suggesting where your problem may have been created. However we first need those numbers from the multimeter.

Notice the price and specs provided by UT's "my own personal PSU". It claims to include essential functions - therefore costs maybe double.

[Undertoad]

My Asus mainboard came with a utility that records the fan speeds and temperatures and voltages as measured by the mainboard. I have never seen these voltages waver one bit even under the maximum load I could manage to put on the system.

[tw]

Originally posted by Undertoad
My Asus mainboard came with a utility that records the fan speeds and temperatures and voltages as measured by the mainboard. I have never seen these voltages waver one bit even under the maximum load I could manage to put on the system.

Only after calibrating that voltage monitor with a 3.5 digit mulitmeter will that motherboard monitor report anything useful. They are selling motherboards on the cheap. 5% resistors are far less expensive than 0.5% and 1 %. Did you notice that little descrepancy in the specs? Or did they just 'forget' to mention that critical information?

Now let's return to fundamentals of quality. There are good components, bad components, and unknown components. Three categories. Unknown components and good components both measure good voltages. Then a sudden failure with massive damage happens. Power supply failure also takes out disk drive, Ram, motherboard, CD Rom, etc. Where was a voltage measurement going to predict the crappy power supply from the unknown category?

Stable voltages only suggest a good supply. Bad voltages say, beyond a doubt, it was a crappy supply. No voltage measurement is going to detect a missing functions in that defective Sparkle supply.

3.5 digit multimeter can identify a failure. It cannot detect all design defects. Many conditions are necesary to define a minimally acceptable power supply. That Sparkle supply is the classic example of defective - even though it always measures good voltage.

Bad voltage measurements will explain why VSP's computer is failing. But a quality supply - the first of three possibilities - demands that the supply meet a long list of critieria. A stable voltage tells us nothing about a good supply. It only says the supply is not bad - today. That Sparkle quickly violates criteria for acceptable - even though its voltage measure OK today.

At this point I am appaulled I should even have to explain simple, fundamental technical concepts. PSU measures good voltage? Therefore it will never damage any computer? Where does this religion come from?

Once VSP has a meter, only then will we start a 'step by step' process to fix his machine. In the meantime, it would be nice to have specifications for his power supply - to avoid other future problems. Today, we need a few minutes of voltage measurements to only begin an analysis. Start by eliminating PSU as reason for failure - before even speculating on anything else.

[Undertoad]

All I know is that my motherboard costs more than my multimeter.

[xoxoxoBruce]

My 3 1/2 digit Fluke was $650.

[glatt]

Question from a computer user, not a computer builder:

Can you pull a power supply from a cheap older name brand computer and have it be more reliable? Seems to me a power supply is a pretty basic component, and if they made them better in the olden days, and you can get old, obsolete computers for less than $50, you can just pull a good power supply out of an old PC.

[BrianR]

Not a good idea because the ratings (wattage) will likely not be sufficient to cover the newer computers' power requirements.

I used to have old computers that would work if I reassembled them, and the PS would have something like a rating of 200w.

My computer now needs more like 300w and IT is an older model as well...800Mhz Celeron, one 10g HD a CDROM and a CDRW.

My next one will have all this and more and thus will have a higher power requirement.

Brian

[SteveDallas]

Besides what Brian said, my experience in fixing "store-bought" computers is that they often skimp on the power supply. I've seen relatively new systems with 70 watt ones!!