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no power to pc

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green250

IS-IT--Management
Sep 22, 2003
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CA
this happened all of a sudden when I press the power button i get nothing I tried another power supply but got same thing, is it possible it is the mobo? but shouldn't I get something even if it is the mobo?
 
If it's the motherboard it's quite likely nothing works.

My advice is to go down to the absolute bare bones. You don't need a hard drive, cdrom, soundcard, modem, network card etc etc for the computer to work. Take it all out. All you need for the computer to start up is the power supply, motherboard, processor, ram. take everything else out and see if it powers up. also, change your power supply lead (I had one go on me the other day - took me ages to realise what it was!!).

If it does boot up as a barebones system, add things one at a time - trying individually to turn on the pc. this way you will narrow down the problem to one particular component.

If it doesn't even start up as a barebones system, come back to us.
 
Thanks for the advice, also what exactly do you mean by a power supply lead?
 
Motherboard may have a LED showing keepalive power available.
This is assuming an ATX.

If you have keepalive then power up switch should feed through the M/B circuits to hit the powerup lead on the PS. Power up is pin 14 (usually green) (1-10 L to R top row) (11 to 20 bottom row with latch) should be around +5 w/ respect to 0 (pin 20 I think) dropping to 0 when the switch is pressed.

Ed Fair
Give the wrong symptoms, get the wrong solutions.
 
Ed Fair
Give the wrong symptoms, get the wrong solutions.


Give really technical answers, get confused looks.
 
If you are using a surge protector then try the reset button on it (if it has one). This can/does get overlooked.
Also verify power from the wall outlet.
 
check the power lead to your power supply (the one from the wall)... try replacing it or plugging it into your monitor to see if you monitor works with it in.

could be a fuse or dodgy connection.
 
sorry franklin.

To troubleshoot power up problems with an ATX M/B /PS you really need a voltmeter.
The M/B connector is a 20 nylon shelled one, and the power on is on pin 14 (usually green wire). If that wire changes from +5 volts (measured against a black wire) to 0 volts when the power on button is pushed and the power doesn't come on, you have a P/S problem.

Ed Fair
Give the wrong symptoms, get the wrong solutions.
 
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