Tower will not turn on

[Leetonsmommy]

Having issues with my tower. Everything worked fine yesterday & nothing today. Try to turn it on no noise nothing but a green light on board. We just replaced power supply 3 days ago, HELP i need my puter for work & school

[Crafty]

Why did you replace the PSU and what PSU is it? I would check that the new PSU is not faulty, take it back to the store and have them check it, or try it in another computer. Also, a word of warning, never ever take a PSU apart because it holds an electrical current even when it is switched off.

[Leetonsmommy]

replaced it b/c it wasn't working i would be on doing m thing & all of a sudden computer would turn off without warning it has been working great since i replaced it until now

[Crafty]

replaced it b/c it wasn't working i would be on doing m thing & all of a sudden computer would turn off without warning it has been working great since i replaced it until now

If it was working fine when you replaced the other one, it leads me to believe that this one may have gone bad - Was it a new one? You could try checking all your connections again just to make sure thats not the problem, like checking the mains the Psu is plugged into and the power lead is fully plugged into the motherboard etc.

[whiper-snaper]

Why did you replace the PSU and what PSU is it? I would check that the new PSU is not faulty, take it back to the store and have them check it, or try it in another computer. Also, a word of warning, never ever take a PSU apart because it holds an electrical current even when it is switched off.

but pulling things apart is the best way to learn first hand how they work.
i do it all the time and have no issues

[reddevilggg]

but pulling things apart is the best way to learn first hand how they work.
i do it all the time and have no issues

If you can afford the hospital bills, go straight ahead. You were advised this for a reason.

[whiper-snaper]

If you can afford the hospital bills, go straight ahead. You were advised this for a reason.

and your point?
i know what im doing!
some people just wont accept people doing things that they have no license to do!
this is y the world is becoming to pc!
1 day u will need to be supervised wipeing ya rear end!

[patio]

and your point?
i know what im doing!
some people just wont accept people doing things that they have no license to do!
this is y the world is becoming to pc!
1 day u will need to be supervised wipeing ya rear end!

Careful with your comments...
This isn't Chat.

[reddevilggg]

and your point?
i know what im doing!

If you know what you are doing, then you must understand the reason for being warned about it.

[Salmon Trout]

Pay little attention to someone who can't spell "whipper-snapper".

[whiper-snaper]

oh well i wont bother posting in the forums cause obviously you r all idiots who think they know everything

[Salmon Trout]

Also, a word of warning, never ever take a PSU apart because it holds an electrical current even when it is switched off.

I don't think is actually true of PSUs in PCs. Were you thinking of microwave ovens?

[Frankie]

Never thought when someone was considering someones safety would it cause such a stir lol. I can send you many more links to say that it is not safe, but if you think otherwise go figure it for yourselves, or at least Google it.

@Salon Trout, It would be interesting to know why you think it's not true? I myself believe it to be true because I have been taught that many electrical devices can hold an electrical charge for weeks after they are switched off, including power supply units.

http://www.computer-how-to-guide.com/power-supply-troubleshooting/failed-power-supply-psu-diagnostic/

http://wiki.answers.com/Q/Why_should_you_never_open_a_computer's_power_supply

[Salmon Trout]

@Salon Trout, It would be interesting to know why you think it's not true? I myself believe it to be true because I have been taught that many electrical devices can hold an electrical charge for weeks after they are switched off, including power supply units.

Those are a couple of quotes from "some guy" type web pages.

So is this really, but it presents the opposing point of view:

http://www.overclock.net/a/capacitor-safety-in-power-supplies

We've all heard it at least once. "Dude, don't open up that power supply, the capacitors will shock you and you'll die! You have to unplug it, flip its switch twenty times, leave it out overnight, then you can open it up; but don't forget to wear rubber gloves and to say the special shock-warding chant!"

It's a tiresome myth, perpetuated by CRT repair technicians and overzealous nervous ninnies. While capacitor safety is very important, when it comes to consumer power supplies life is a lot simpler than what this myth would lead you to believe.

[...]

a capacitor can store a charge for a period of time after the circuit itself is no longer charged. While diodes, transistors, and resistors become inert instantaneously or within nanoseconds of voltage difference being lost, the capacitors in consumer electronics can hold onto charge for up to whole seconds.

Whole seconds. Consider a moment, The primary capacitors of even the most powerful ATX power supply, 1200W and up, would drain to safe levels (voltage too low to overcome your body's natural resistance) in less than two or three seconds when fully charged, even if left entirely alone, due to residual draw in the circuit. With lower wattage PSUs the discharge is much quicker; under 500W, a tenth of a second is not unlikely. The charge held by electrolytic and polymer capacitors in PSUs is not that extreme, and the natural resistance in these circuits is low. The capacitors discharge quickly and present little danger of shocking unless you're mucking around with the PSU while it's on (in which case you have more problems than just lax capacitor safety).

I have been building and fixing electronic equipment (including vacuum tube stuff using high voltages) since the 1960s and worked for a number of years as an electronic technician and also repairing TVs.

And another...

http://www.jonnyguru.com/forums/archive/index.php/t-7486.html

I've tried it with a Delta Basiq. Primary cap held a meaningful charge for all of 10 seconds, after that it was down to a couple volts. Gotta love bleeder resistors.

Even with no bleeder resistor the caps discharge themselves quickly.

On that Jonnyguru page there is mention of items called "X-Caps" which are used to filter electrical noise in the AC input voltage; these were alleged to be dangerous; this is wrong too; these self discharge within 1/50 of a second of the power being disconnected. (1/60 in the USA). Even if a fault such as an open-circuit bleed resistor (or it's a Chinese $15 special with none fitted) prevented this, they would be safe to touch within 15-20 minutes.

[Crafty]

People will have a different take on this, but I would just replace a PSU rather then risk messing about with it's innards. I wouldn't recommend it to anyone reading in a forum just in case the worst happened and i stick by what I said. Sorry for trying to help, I wasn't expecting there to be an inquest  .  Maybe this thread should be locked now because it's going nowhere.