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Recently began having random abrupt computer shutdowns.
Remembering other questions about this on VideoHelp and the probable solution(s), I replaced the power supply.
Problem solved, as recommendations here suggested it would.
I'm curious about what likely failed in the PS:
o When the computer would shut down, the "NUMLOCK" light would stay illuminated. (I suspect there's a hi/low voltage factor).
o Not that it might make good economic sense, is this a repairable condition? Not sure I would even try, but I *am* curious.
Thanks for any insights!
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As always with failed electronics, bad capacitors are a likely cause.
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I presume the likeliest suspects are those that will "get your attention" if mishandled?As always with failed electronics, bad capacitors are a likely cause.
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Basic law of entropy, nothing stays good forever.Originally Posted by CobraPilot
How old was the power supply? -
About 5 years old.How old was the power supply?
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Do you live in a place with frequent brown outs? I do. I live in a suburb in a major metropolitan area of the USA and I feel like I've got a damn third world power company providing me with electricity. On the average my house has a brown out every month. I really should have known better, but sometimes cheap trumps smart. For years I ran my PCs without any UPS devices at all. I used to lose a power supply every year on average to a brown out. I've seen many strange PC problems that have been fixed by replacing the power supply. I used to also have to completely reinstall Windows about once a year because the constant brown outs would eventually put my boot drive in a crazy state where it would no longer boot but I could recover everything I could find on it and running every Windows repair tool I could find could never get the drive to boot again. All those problems went away once I started using a UPS. I even have a small one that my HDTV is hooked up to just to protect it from the brown outs. I can lose my power when it rains - good grief! Seriously - if we have a very strong rain, I am in serious danger of my power cutting out at some point. I mention this because most people I know do not have UPS devices at home. So yeah, power supplies can just die and 5 years is pretty good for one to last but if you're suffering from brown outs like I do, that could also be a big factor if you aren't protected by a UPS device.
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That's old.Originally Posted by CobraPilot
It's like a car after a few years things start to break down, it is really not any different with computers. -
I wouldn't go as far as "as always with failed electronics" ... it's actually more the case that if a cap went something upstream failed and took it out.Originally Posted by usually_quiet
But there was a rash of bad caps from Asia ... see:
https://en.wikipedia.org/wiki/Capacitor_plague
However, you're dealing with some serious voltages in there, potentially lethal. Not recommended if you have no idea about electronics.
And I don't think a PS that old is worth the bother anyway. -
Yes, as already stated, the amount of stored voltage in a PSU is potentially dangerous.Originally Posted by CobraPilot
I presume the likeliest suspects are those that will "get your attention" if mishandled?As always with failed electronics, bad capacitors are a likely cause.
Electrolytic capacitors in particular dry out over time, but other factors can speed up the process. http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx -
@jman98 if you are subject to brownouts, pay especial attention to electric motors on refrigerators, dryers, AC units, washing machines or similar. They die very quickly and expensively when the voltage drops. Just listen to a fridge trying to start at ~80VAC. Lots of humming.
And most electric companies can be held responsible if they damage your appliances. But they will rarely tell you that. You have to demand a claim form and then don't take their first offer. This applied when I lived even if a lightning strike on the power line was the cause of a spike. Brownouts may be different , but I would still ask for a claim form.
I lose a computer power supply usually once a year. I used cheapie ones years ago and I then I lost the whole PC. Though strangely enough the floppy drive survived. And when it blew there were sparks and smoke. Now I stick with name brands and I still have an occasional failure, but it rarely damages the PC. I have about twelve PCs that regularly run at present, not counting laptops. The last PS that died was a Corsair 600W on one of my servers about a month ago. I have Antec, Corsair, Thermaltake, SeaSonic, OCZ and a few other brand PSs. All of them are good brands, mostly 500W to 700W versions, some modular. None were overworked or ran hot. Their failures were random. The most common failure was not booting the PC or just booting for a few seconds then shutting down. On that Corsair one the 3V bus died and the MB or the PS shut it down for protection. 
If I have a PC that won't start or won't boot and nothing is obvious, I change out the PS first and most of the time that fixes it. Occasionally it's a motherboard failure, but that's mostly with the economy motherboards. I haven't lost a drive, CPU, RAM in quite a few years to a PS failure, mostly due to good PSs that handled the fault.
If you have voltage spikes, what often blows in a PS is the MOV (Metal Oxide Varistor) That's like a fuse that responds to voltage, not amperage. The MOV destructs when overloaded, opening the circuit. They are easy to spot when blown. PSs rarely have fuses these days, they rely on sophisticated voltage, current and short detecting circuitry. Much more dependable. MOVs are also common in outlet power strips. Most PSs can handle voltage variations from 80VAC to 250VAC without problems. Even spikes and brownouts are less of a problem to a PC PS than to AC motors or TVs.
Capacitors in PSs do fail, but that can mostly be spotted if you pull the PS apart. I wouldn't try to replace a capacitor there as it may have been destroyed by a different part of the PS failing. You aren't as likely to see huge capacitors in a newer PS. They use smaller capacitors and inductors and the PSs can reach efficiencies of over 80% quite easily. Capacitors can hold a charge for a while, so do be careful probing around them. Best to unplug a PS and wait an hour before opening one.
Modern PSs are switching types and convert the 50/60Hz AC line to high frequency pulses that are more efficient to transform to lower voltages. There is a lot a amperage available in a PS, especially on the 3V CPU lead. Modern PSs can put out 50 amperes or more, enough to weld with. Don't be shoving a metal screwdriver in there when they are on.
But I do recommend using a good brand PS. One simple way to check on PS quality is the weight. A good quality PS will weigh quite a bit more than a cheap one. -
Just like a car, computers need regular oil changes. Tyres wear out and need replacing. Brakes need to be checked regularly, discs machined.... a PC is just like a car except for not being much like a car at all. Maybe more like a car radio or sound system that's likely to still be working when the car itself is scrapped.Originally Posted by newpball
That's old.Originally Posted by CobraPilot
It's like a car after a few years things start to break down, it is really not any different with computers.
Appliances such as TVs or refrigerators etc can keep working for well over ten years. In fact they're expected to. Why aren't they like cars?
There's a small form-factor Compaq Pentium 3 PC in this house. That'd make it around 15 years old. It's still used roughly 3 hours per day on average (my mother likes playing card games). It's the original PSU. -
Thanks for all the comments, alerts (warnings!), and reality checks.
Time to (carefully) open the case, salvage the cooling fan (since it still works), and toss the rest! -
One of the outputs of a PC power supply is the +5V standby line that is mainly used for the mainboard power on/off circuit, and the keyboard (PS/2).Originally Posted by CobraPilot
For the nth time, with the possible exception of certain Intel processors, I don't have/ever owned anything whose name starts with "i".
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Ha, so you hate throwing away usable parts too. Into the parts bin it goes!Originally Posted by CobraPilot
Pull! Bang! Darn! -
Absolutely! I was recyclin' before recyclin' was COOL!Originally Posted by fritzi93
Ha, so you hate throwing away usable parts too. Into the parts bin it goes!Originally Posted by CobraPilot
Although not from that part of the country, I ran across this Northeast USA Yankee-ism and have determined I've done this for years:
"Use it up,
wear it out.
Make it last, or
do without."
What this classic rhyme doesn't warn against is a Lovely Wife who isn't wild about the "numerous" parts bins about her domicile!
Thanks again to everyone who provided insights -- and warnings!
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