Thanks Mark - exactly what I needed to know.

One other thing - what's the significance of the -5v and -12v that derive
from some cables. (I assume that the dash indicates a 'minus' value)?

Ian Porter
Computer Guys Inc.
Arrowtown
New Zealand
[log in to unmask]

----- Original Message -----
From: "Mark Rode" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, January 30, 2003 12:03 PM
Subject: Re: [PCBUILD] Power Supply problems & testing with a multimeter


> For an AT power supply, you need only hook a load up to it, like a fan, or
> a hard drive, plug it in, turn it on and check the yellow and red leg on
> any power connector. To do this put your meter on DC volts, plug the
> positive (red) probe into the yellow and then red wire, and the negative
> (black) probe into any black wire. Yellow should be at 12+ and Red  should
> be at 5+ regardless of the load. There is no reason why you can't run this
> test on a running PC , while the PS is under load. In fact that would be
> the ideal test.
>
> For an ATX powersupply you will need to override the signal wire in order
> to turn it on. They sell a plug in that will simulate the motherboard
> signal switch, but you can make your own with a paper clip. On the ATX
> Motherboard Power  Block ...put one side of the paper clip into the green
> wire (signal) slot, and the other end into any black (ground) wire. Plug
in
> some kind of load , like a fan. and turn the PS on by either plugging it
> in, or the best way is to use a surge protector with a switch on it.
>
> Rode
> The NOSPIN Group
> http://freepctech.com
>
>
> >If anyone knows how to do this, I'd be interested to hear.  Several times
> >I've wanted to test a power supply on the work bench, but when they're
not
> >connected to a computer, they don't function at all, ie you can feed
power
> >in, but nothing comes out the other end.
> >
> >I have an idea that you can short out a couple of the connector pins, to
> >simulate the motherboard switch, but I don't want to try it out without
> >knowing the right ones.
> >
> >Incidentally, if the original poster (sorry, I forgot who that was) is
still
> >wondering how to use a meter, set it to 10 volts DC.
> >
> >The power supply puts out two voltages, 5v and 12v.  On my non-digital
> >meter, there are several scales on its' face, so 12v doesn't kick it off
the
> >clock.
> >
> >Ian Porter

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