PSU no -5 volt rail, question

My brother owns a Pentium III computer. His power supply died and he purchased a 460 watt switching power supply [from Qtechnology, 460 watt, model number QT-03460G]. He called me and asked if I would install it, which I did. After installing it, I booted into BIOS and checked voltage.

He has a Pentium III computer.

The BIOS reported a problem with -5 volts [it was reading -12 volts]. I checked the cable to the motherboard and found that there was no wire and pin for -5 volts coming from the PS.

We found no written material in the box that the PS came in, the outside of the box listed voltages for the PS, -12 volts was listed but -5 volts was not.

A computer uses 1s and 0s to comunicate data, greater than +3 volts means 0, less than -3 volts means 1, close to 0 volts means no data is being transmitted.

So, are newer motherboards/power supplys only using -12 volts? Will using a PS with only the -12 volt line work in a Pentium III mainboard?

Thank You,

Dan
 

lonelypauly

Distinguished
Apr 27, 2005
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So you say it's a Pentium III? It sounds like that PSU is rated for a P4, which is plenty for a P3. I seriously doubt that there would be any difference PSU-wise, because P3's would be blowing up all over the place.

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Crashman

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Set BIOS to ignore the -5v reading as I doubt any hardware is using it.

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