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Low voltage reading on +5v, -5v, and -12v rails

Last response: in Components
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October 29, 2006 2:01:23 PM

I have been trying to diagnose a problem with my system (I get a BSOD once every other day or so - Windows says its either CPU, RAM, MB, or PSU related, for whatever thats worth). According to SpeedFan, my +5v, -5v, and -12v rails are all reporting voltages in the following ranges:

+5v: 2.5v - 4.9v, averages around 3.5v
-5v: -0.8v - -4.5v, averages around -4v
-12v: -2v - -12.5v, averages around -6v

+3.3v and +12v rails are within 1% of ideal

These are all aberrantly out of spec, but I am left to wonder if the problem might not lie in the MB, with its voltage sensors.

If indeed, the problem lies with the power supply, what symptoms might I observe with voltages widely out of spec? Where can I find the +5, -5, and -12v rails to test the voltages on them?
October 29, 2006 2:35:22 PM

could you give the name and info of you PSU?
October 29, 2006 2:38:10 PM

A few things: some software based volt readers skew your readings...Either borrow a volt-meter or check the rails in the BIOS.

What PSU are you using? Low rails/bad PSU can most certainly cause BSODs...

~Ibrahim~
October 29, 2006 11:11:42 PM

I have an Enermax Noisetaker EG495AX-VE (485 watt w/ active pfc).

I know I need to check the voltages with a volt meter, I'm interested in knowing where to check them. If I grab a reading off an unused molex connector, will it give me valid results? Or am I going to have to jerry rig something to test the voltages on the 24 pin MB connector?
!