Computer Will Not Power Up

g-paw

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One of my computers will not power up. Tried a different PSU and still nothing. It was working fine last night but when I went to turn it on today, nothing. Checked all the wiring from the case and it's fine. Any idea's? One other question, will a power supply start up if it's not in a computer? Have tried just plugging 3 PSUs in and turning them on and none will turn on, one is brand new? Tried both the UPS, which has power, e.g., the monitor orange light is lit when it's plugged in as well as a power strip that has the red light lit. Do not have an extra mobo so can't try swapping. Thanks
 

maury73

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In order to start the PSU you must connect static loads to at least the +5V and +3.3V rails, and short tho ground the start pin.
Anyway I think it could be the mobo or the CPU.
 

waylander

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You can short pin14 (green wire) with any black wire to start a psu when not connected to the motherboard. Make sure you have a fan or something plugged in first.

If your psu's are fine then it does sound like the motherboard.

Please list all your specs, for someone with almost 400 posts you should know this.
 
One of my computers will not power up. Tried a different PSU and still nothing. It was working fine last night but when I went to turn it on today, nothing. Checked all the wiring from the case and it's fine. Any idea's? One other question, will a power supply start up if it's not in a computer? Have tried just plugging 3 PSUs in and turning them on and none will turn on, one is brand new? Tried both the UPS, which has power, e.g., the monitor orange light is lit when it's plugged in as well as a power strip that has the red light lit. Do not have an extra mobo so can't try swapping. Thanks

Maybe the power on switch on your case has come loose. Check behind the front panel, see if the switch is in place and working properly.
 

g-paw

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Thanks for everyone's help. Sounds like if I plug in the PSU and connect the 20 pin and 4 pin power connector and everything else is as it should be and the machine doesn't start, it's most likely the motherboard? Hopefully, it's still under warranty. Thank goodness for my Dell PIII backup. I'm definitely not a big Dell fan anymore but their old machines seem to run forever. Got 2 PIIIs still running
 

pengwin

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Thanks for everyone's help. Sounds like if I plug in the PSU and connect the 20 pin and 4 pin power connector and everything else is as it should be and the machine doesn't start, it's most likely the motherboard? Hopefully, it's still under warranty. Thank goodness for my Dell PIII backup. I'm definitely not a big Dell fan anymore but their old machines seem to run forever. Got 2 PIIIs still running

nah, HP vectra's. Had a Pentium 1 350Mhz one i think. still runs.
 

angry_ducky

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Thank goodness for my Dell PIII backup. I'm definitely not a big Dell fan anymore but their old machines seem to run forever.

Indeed, they do. My little brother has a Dell from 1998. It's got a P3 (450MHz of POW3R!), 128MB of SDRAM (you can run TWO programs at once!) and a Diamond Viper V550 graphics card (feel the [/b]SP33D of the NEW AGP GRAPIHCS BUS! Experience ALL the latest 3D games like SOLITAIRE!). The only thing that's gone wrong was when the hard drive died earlier this year.