Testing LPX Power Supply

  • Thread starter Thread starter J.T.
  • Start date Start date
J

J.T.

I have this old computer that a friend asked me to fix. I determined it
has an LPX power supply which I think is broken. I bought a 22 range
digital multimeter from Radio Shack. Now what? I'm not very familiar
with electricity. I don't even know what "22 range" means. As near as I
can figure, I have to put the black lead on a metal part of the chassis
as a ground (don't really know what that is either) and the red lead on
what I'm testing. I have my eye on those two six pin connectors with all
the colors. What numbers am I looking for on my multimeter on what
colors? Also, how do I set the multimeter for the right thing? Any help
is appreciated.

BTW, when I turn on the machine all I hear is fans and a hard drive.
Then a blank screen. The monitor works on a different machine. No beeps.
My other friend suggested checking the power supply. I can get a
replacement fairly cheaply if that's what it is.
 
J.T. said:
I have this old computer that a friend asked me to fix. I determined it
has an LPX power supply which I think is broken. I bought a 22 range
digital multimeter from Radio Shack. Now what? I'm not very familiar
with electricity. I don't even know what "22 range" means. As near as I
can figure, I have to put the black lead on a metal part of the chassis
as a ground (don't really know what that is either) and the red lead on
what I'm testing. I have my eye on those two six pin connectors with all
the colors. What numbers am I looking for on my multimeter on what
colors? Also, how do I set the multimeter for the right thing? Any help
is appreciated.

BTW, when I turn on the machine all I hear is fans and a hard drive.
Then a blank screen. The monitor works on a different machine. No beeps.
My other friend suggested checking the power supply. I can get a
replacement fairly cheaply if that's what it is.
Click to expand...

I'm not exactly sure what the different colors are for on the six pin
connectors (which are for the motherboard, I believe), but any 4 pin
ones are for disk drives and have two different voltages running in
them. On the 4 pin socket, the middle two are ground, which is
probably interchangable with the "case ground" you talked about. On
one side is a 5Volt wire, and the other a 12Volt wire. To test those,
set your multimeter to the nearest setting above 12V, in the DC Volts
area. If you have power on those plugs, you probably have power on
the motherboard plugs.

Hope that's not to complicated,

Aaron
 
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