Power Supply Voltage beyond tolerance?

[kyle.theguy.smith]

I'm trying to determine if my power supply is keeping my computer from booting. The computer was knocked on it's side and now I'm not getting any image on the monitor.

When I voltage tested the 24 pin connector, the 14th pin is supposed to have a -12 volt reading with a 5% tolerance. The reading is -11.23, .17 more than it should have for the tolerance, would that stop the computer from booting?

Also worth noting, when I turn on the power supply switch in the back, the motherboard automatically comes on, and if I hold down the power button to force shut it off, it powers back on after a few seconds.

 

[jay32267]

Yes it can stop the computer from booting, Those tolerances are very important.

 

[Zerk2012]

I'm trying to determine if my power supply is keeping my computer from booting. The computer was knocked on it's side and now I'm not getting any image on the monitor.

When I voltage tested the 24 pin connector, the 14th pin is supposed to have a -12 volt reading with a 5% tolerance. The reading is -11.23, .17 more than it should have for the tolerance, would that stop the computer from booting?

Also worth noting, when I turn on the power supply switch in the back, the motherboard automatically comes on, and if I hold down the power button to force shut it off, it powers back on after a few seconds.

The -12 volt rail is + - 10% not 5%.
https://www.lifewire.com/power-supply-voltage-tolerances-2624583
Your problem sounds more like a short not a power supply problem.

 

[jay32267]

I still would never run with 11.23V on a 12V rail. 11.23 is too far out imo. If the 12V rail was shorted it would not read 11.23V.

Although I must admit....I didn't see the "-" until just now. I at first thought it was your positive 12V rail. Being it's your negative rail...I don't throw as much weight behind my earlier statements...-11.23 would still bother me though.

 

[Zerk2012]

11.3 on the -12 volt rail is no big deal either your in the tolerance or not.
Most modern boards dont really use the -12 rail but could be used for a SATA or LAN i guess.

He knocked the PC over now it turn itself on so something is shorted in the PC it will not try to power up untill the power supply pins are jumped.

Could of damaged the power supply, motherboard, power button, or other things but something is shorted.
First thing I would be looking at is the motherboard either shifted on the standoffs, was damaged in the standoff mounting area, or heavey CPU cooler damaging that area of the board.