Computer Won't Turn On

[Infested Cats]

My brother has had his computer for about 2-3 years now, and recently, he went to turn it on, and nothing happened. Literally, after pressing the "power button" on the case, there is nothing. No activity of any sort (fans, hds, nothing).

I checked all the connections, and everything seems to be in place. Other than that, I haven't attempted anything else. I figure it could either be the Motherboard or the Power Supply.

Any ideas?

[boyzeee]

sounds like power supply to me, i take it you have checked the fuse in the plug? ;)

[cwctv]

Or the power button is u/s won't be m/board cause the power would still kick it up just wouldn't go anywhere.
To check the switch follow the power on lead to the m/board take the cable off then slowly put a small screwdriver to the two pins and don't touch anything else.

[DL.]

You can test the power supply by shorting two pins but take a look at this diagnostic first.

http://www.fonerbooks.com/power.htm

Then maybe try this but double check your color codes first.

http://www.extensiontech.net/articles/howto/pstu/

[boyzeee]

1st try plugging a lamp you know works into the same socket to make sure you got power then check the fuse in the lead is ok, try a different lead to be sure and as cwctv said check the switch itself ;)

[Infested Cats]

1: Tried using a differnt power cord... nothing

2: Tried a differnt powersupply... nothing

3: Tried resetting the CMOS... nothing

3: Tried screaming and cursing at it... nothing

[boyzeee]

you definately got power at the socket?

[Infested Cats]

Originally posted by boyzeee@13 November 2003 - 21:11
you definately got power at the socket?
I don't see how I couldn't... It's plugged into a powerstrip.

[cwctv]

Then go try the switch as said

To check the switch follow the power on lead to the m/board take the cable off then slowly put a small screwdriver to the two pins and don't touch anything else.
these can and do go down seen a few in my time.

[clocker]

What did you do when you "tried another power supply"?

Have you tested the on/off switch?

[Infested Cats]

Originally posted by clocker@13 November 2003 - 21:19
What did you do when you "tried another power supply"?

Have you tested the on/off switch?
When i tested another power supply, I fetched my spare one, unplugged the previous power supply's connections, and reconnected with the other powersupply.

havent tried switch yet.

[boyzeee]

Originally posted by Infested Cats+14 November 2003 - 01:17--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Infested Cats @ 14 November 2003 - 01:17)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-boyzeee@13 November 2003 - 21:11
you definately got power at the socket?
I don&#39;t see how I couldn&#39;t... It&#39;s plugged into a powerstrip. [/b][/quote]
I wouldnt overlook not having any power, it happened to me a couple of years ago and i tried everthing else thinking i had power and it was a loose wire in the socket itself :rolleyes: i wasnt impressed to say the least :blink: its just a case of going step by step ruling things out, power is the first thing i check&#33;&#33; ;)

[lynx]

Assuming you&#39;ve checked everything else, take a close look at one of the fans as you press the power button. If it jerks a little, the problem is either in the power supply, or that the motherboard is not returning a powerok signal (pin 8 on the mobo power connector). If this is the case, the quickest way to check is to borrow a good power supply and try it in the faulty system (just connect the motherboard). If it doesn&#39;t work then the mobo is almost certainly faulty. If it works, the fault is probably in the old PS, but you can then do furhter checks to make sure some other component is not overloading the PS.

[Infested Cats]

The powercord is tight...

the spare power supply wouldnt work

i did the screwdriver trick

screamed and shouted some more...

nothing. cold dead.

[_John_Lennon_]

Originally posted by Infested Cats@13 November 2003 - 20:34
The powercord is tight...

the spare power supply wouldnt work

i did the screwdriver trick

screamed and shouted some more...

nothing. cold dead.
Have you determind yet though that power is actually going to the power strip?

[Infested Cats]

Originally posted by _John_Lennon_@13 November 2003 - 21:44
Have you determind yet though that power is actually going to the power strip?
The power strip is getting power becasue 1) the light on it is lit and 2) everything else that&#39;s plugged into it is functioning.

[_John_Lennon_]

So its not the power strip,
not the power supply.

Sounds like motherboard I guess.

Oh, btw, try disconnecting all non essiental devices too, I.E, everything but the powersupply, and video card from the motherboard, then try and boot it up.

[balamm]

You didn&#39;t happen to set it to "soft off/on" did you? Have you held the power switch in for 10 seconds?

[clocker]

Well, look who&#39;s back.

Welcome.

[random nut]

Originally posted by Infested Cats+14 November 2003 - 04:51--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Infested Cats &#064; 14 November 2003 - 04:51)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-_John_Lennon_@13 November 2003 - 21:44
Have you determind yet though that power is actually going to the power strip?
The power strip is getting power becasue 1) the light on it is lit and 2) everything else that&#39;s plugged into it is functioning. [/b][/quote]
You should let some computer expert have a look at it.

[Virtualbody1234]

On the back of the tower there is a switch on the power supply. Is that switch on when you press the button?

[Smurfette]

Originally posted by Infested Cats+14 November 2003 - 02:51--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Infested Cats &#064; 14 November 2003 - 02:51)</td></tr><tr><td id='QUOTE'><!--QuoteBegin-_John_Lennon_@13 November 2003 - 21:44
Have you determind yet though that power is actually going to the power strip?
The power strip is getting power becasue 1) the light on it is lit and 2) everything else that&#39;s plugged into it is functioning.[/b][/quote]
But have you...
3) swapped tried the computer plug in another socket on the strip? There could be a fault with just that socket.

Also, use a multimeter to check the pins on the mobo that the power switch connects to, to make sure that the small voltage is being supplied to the switch. If there is a voltage check that it&#39;s being returned from the power switch when you press it. If there isnt, check that the small voltage is actually coming from the power supply to the board. You will need the mobo&#39;s manual for this, to know which pins to test.
If you&#39;ve got power going in from the PSU but none going to the switch, it&#39;s the mobo at fault.
If there is power to the switch, check the pin that returns voltage to the PSU when the power button is pressed and if there&#39;s none when you press the switch or join the power switch pins, the mobo is at fault.
If there&#39;s no small voltage from the PSU check its fuse - not just the one in the plug, there is one inside as well. Many multimeters will check fuses with a &#39;continuity check&#39; function, or even by checking for resistance (infinity = faulty). If the fuse is OK and you&#39;ve made sure there is power to the PSU, the PSU is faulty.

I don&#39;t know if you followed that but here&#39;s a very simplified explanation to help clarify how ATX computers get &#39;turned on&#39;...
The PSU supplies a small voltage to the mobo and the mobo supplies it to the power button on the case.
When you press the power button, that small voltage returns down to the other pin on the mobo that the switch connects to.
When the mobo detects that return voltage, it sends another small voltage to the PSU.
When the PSU detects that small voltage, it turns on the +12 and +5 voltage lines, the it&#39;s fan comes on and, hopefully, the computer comes to life.

That should help anyone troubleshoot power problems but please note: If you are not sure what you are doing or not confident working inside an electrical appliance with mains voltage supplied to it - leave the damned thing alone and get a professional in.

[SciManAl]

If you are not sure what you are doing or not confident working inside an electrical appliance with mains voltage supplied to it - leave the damned thing alone and get a professional in.

you mean like my cousin earl??