+12V Rail
- Thread starter L0rdMike
- Start date
Soldato
- Joined
- 9 Sep 2008
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- Glasgow
What is it giving out?
Soldato
- Joined
- 7 Jul 2009
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- 16,234
- Location
- Newcastle/Aberdeen
What's the actual PSU?
11.4V is the lowest allowed by the ATX specification. (12V +/- 5%). Its worth checking the other rails too though, the 3.3V rail is still used for the memory on many motherboard (perhaps all), I believe 4% variation is permitted on that rail. I dont even bother checking the 5V rails anymore, nothing important on them
, I think the USB power supplies, keyboard/mouse etc are run from 5V. Hard disks use 12V and 5V but realistically the 5V rail should be so lightly loaded these days its gonna be fine even on a trashy power supply.Also remember, motherboards are pretty lousy at measuring the rails, your better off with a £10 digital multimeter than putting to much faith in what the motherboard reads. Your 11.5V could be anything from 11V to 13V if your going by the motherboards measurements alone.
In practice the quality of the DC output is more important than the absolute voltage, under load, some powersupplies have very dirty DC outputs, and that's one of the biggest causes of system instability. Unfortunatly you need an oscilloscope to measure and view how much noise and ripple there is on the outputs.
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Well, voltage wise I wouldnt worry, however smoke and burnt wires... I assume your actually talking about smoke from the PSU rather than the device that was plugged in wrong.. It could well have damaged the PSU's ability to deliver clean stable power, I would certainly point my finger at a formerly overloaded PSU as a potential source of instability. (Although the only way to test this is to use the questionable PSU in a known good computer, or a good PSU in the known unstable computer)
