Power Supply Tester

All,

I have been working on this pc, (Dell Dimension 2300 2 GHz, 256 MB, 40 GB),
and despite being only 2 - 3 years old, the inside was filthy. I cleaned it
out very well with compressed air, afterward, it would not start, and in
fact, would turn slightly( the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able to get the pc to
turn on normally. I reimaged, and everything appears to be fine, However,
today I borrowed a power supply tester, and when I tested it, one of the 5
volt lights does not come on, (the - 5V), and overall, both the "good" light
and the 'danger' light come on.
Does this mean that the power supply is bad? The computer seems to be
running fine now.


RF

Could be getting ready to go....I would leave it on for a long time and see
if it starts rebooting.

--
Mark
MCSA, CNA, A+, Net+, iNet+, Server+
"RF" wrote in message
newscYOc.189960$a24.105834@attbi_s03...
All,

I have been working on this pc, (Dell Dimension 2300 2 GHz, 256 MB, 40
GB),
and despite being only 2 - 3 years old, the inside was filthy. I cleaned
it
out very well with compressed air, afterward, it would not start, and in
fact, would turn slightly( the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able to get the pc
to
turn on normally. I reimaged, and everything appears to be fine, However,
today I borrowed a power supply tester, and when I tested it, one of the 5
volt lights does not come on, (the - 5V), and overall, both the "good"
light
and the 'danger' light come on.
Does this mean that the power supply is bad? The computer seems to be
running fine now.


RF

A side note, this is a P4 power supply. I don't know if that makes a
difference or not.

Thanks,

RF

RF wrote:
All,

I have been working on this pc, (Dell Dimension 2300 2 GHz, 256 MB, 40 GB),
and despite being only 2 - 3 years old, the inside was filthy. I cleaned it
out very well with compressed air, afterward, it would not start, and in
fact, would turn slightly( the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able to get the pc to
turn on normally. I reimaged, and everything appears to be fine, However,
today I borrowed a power supply tester, and when I tested it, one of the 5
volt lights does not come on, (the - 5V), and overall, both the "good" light
and the 'danger' light come on.
Does this mean that the power supply is bad? The computer seems to be
running fine now.


RF


The tester is more that likely for standard AT or ATX type power
supplies, however, Dell uses a proprietary power supply and the pin outs
would be different.

--
Danny Kile
Please reply to the Newsgroup ONLY

"Dogs come when they're called, CATS take a message and get back to
you." Mary Bly

Howdy!

"RF" wrote in message
newscYOc.189960$a24.105834@attbi_s03...
All,

I have been working on this pc, (Dell Dimension 2300 2 GHz, 256 MB, 40
GB),
and despite being only 2 - 3 years old, the inside was filthy. I cleaned
it
out very well with compressed air, afterward, it would not start, and in
fact, would turn slightly( the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able to get the pc
to
turn on normally. I reimaged, and everything appears to be fine, However,
today I borrowed a power supply tester, and when I tested it, one of the 5
volt lights does not come on, (the - 5V), and overall, both the "good"
light
and the 'danger' light come on.
Does this mean that the power supply is bad? The computer seems to be
running fine now.

I'd cross check - certain Dells use a non-standard wiring for the
ATX power supply, and such will require an adapter for most ATX testers to
work properly.

RwP

RF wrote:

I have been working on this pc, (Dell Dimension 2300 2 GHz, 256 MB, 40 GB),
and despite being only 2 - 3 years old, the inside was filthy. I cleaned it
out very well with compressed air, afterward, it would not start, and in
fact, would turn slightly( the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able to get the pc to
turn on normally. I reimaged, and everything appears to be fine, However,
today I borrowed a power supply tester, and when I tested it, one of the 5
volt lights does not come on, (the - 5V), and overall, both the "good" light
and the 'danger' light come on.
Does this mean that the power supply is bad? The computer seems to be
running fine now.

The need for a -5v output on the PSU was removed from the ATX specification
in April, 2003. (ver 1.3)

http://www.formfactors.org/developer...20PSDG2.01.pdf

On Sun, 01 Aug 2004 02:04:19 GMT, "RF"
wrote:

All,

I have been working on this pc, (Dell Dimension 2300 2 GHz, 256 MB, 40 GB),
and despite being only 2 - 3 years old, the inside was filthy. I cleaned it
out very well with compressed air, afterward, it would not start, and in
fact, would turn slightly( the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able to get the pc to
turn on normally. I reimaged, and everything appears to be fine, However,
today I borrowed a power supply tester, and when I tested it, one of the 5
volt lights does not come on, (the - 5V), and overall, both the "good" light
and the 'danger' light come on.
Does this mean that the power supply is bad? The computer seems to be
running fine now.

-5V is irrelevant for a semi-modern PC, that voltage is "often"
still implemented on an ATX only due to spec, "true"
compatibility with some odd design never seen in typical PC. On
a Dell or any typical system not using -5V, you can completely
remove -5V line and expect no problem, other than a hardware
monitor type warning "if" that voltage is monitored at all. When
a system does not use any particular voltage rail, it is common
for that rail to be out of spec since there is no load on it,
unless the power supply itself has a built-in load, which isn't
to be expected on that rail.

Perhaps a more important question is, if everthing appears fine,
why the further testing?

"RF" wrote in message news:DcYOc.189960$a24.105834@attbi_s03...

I have been working on this pc, (Dell Dimension 2300 2 GHz,
256 MB, 40 GB), and despite being only 2 - 3 years old, the
inside was filthy. I cleaned it out very well with compressed
air, afterward, it would not start, and in fact, would turn
slightly (the fans would move), just by plugging it in.
After I took it apart and re-cleaned everything, I was able
to get the pc to turn on normally. I reimaged, and everything
appears to be fine, However, today I borrowed a power supply
tester, and when I tested it, one of the 5 volt lights does
not come on, (the - 5V), and overall, both the "good" light
and the 'danger' light come on. Does this mean that the
power supply is bad? The computer seems to be running fine now.

I have a couple of mobos made in 1997 that don't use the -5V or -12V,
so I wouldn't worry about that. But I also wouldn't trust any PSU
tester because one I borrowed said that a PSU was OK even though its
+12V rail was at about 10.5V and kept the HD from spinning. It's
better to buy a cheap digital multimeter and learn how to use it
because not only will it be a lot more accurate (2% error, worst
case), but it can be used for testing lots of other things.

larrymoencurly wrote:

I have a couple of mobos made in 1997 that don't use the -5V or -12V,
so I wouldn't worry about that. But I also wouldn't trust any PSU
tester because one I borrowed said that a PSU was OK even though its
+12V rail was at about 10.5V and kept the HD from spinning. It's
better to buy a cheap digital multimeter and learn how to use it
because not only will it be a lot more accurate (2% error, worst
case), but it can be used for testing lots of other things.

Yeah I second that. A cheap tester can be $9 on sale at Radio Shack,
and blows the doors off a single-purpose tester. Even a nice meter can
be had for $40, or you can blow a week's salary on a Fluke if you like.
Having R, V, and I testing is nice, although I like capacitance
testing too. Now my question is, does the single-purpose tester put the
voltage source under load? It's possible for a supply to do well under
no load, and drop miserably under load. No supply on the planet is an
ideal voltage source.

I wonder why - 5 V is more rare? Either the - 5 V is derived from some
onboard regulator, or it's not needed. And 5 V is more for TTL, so
perhaps that's been superceded by other topologies.

michael

Michael wrote:

larrymoencurly wrote:

I have a couple of mobos made in 1997 that don't use the -5V or -12V,
so I wouldn't worry about that. But I also wouldn't trust any PSU
tester because one I borrowed said that a PSU was OK even though its
+12V rail was at about 10.5V and kept the HD from spinning. It's
better to buy a cheap digital multimeter and learn how to use it
because not only will it be a lot more accurate (2% error, worst
case), but it can be used for testing lots of other things.


Yeah I second that. A cheap tester can be $9 on sale at Radio Shack,
and blows the doors off a single-purpose tester. Even a nice meter can
be had for $40, or you can blow a week's salary on a Fluke if you like.
Having R, V, and I testing is nice, although I like capacitance testing
too. Now my question is, does the single-purpose tester put the voltage
source under load? It's possible for a supply to do well under no load,
and drop miserably under load. No supply on the planet is an ideal
voltage source.

I wonder why - 5 V is more rare? Either the - 5 V is derived from some
onboard regulator, or it's not needed.

It's no longer needed. Was there for older technology that needed a
negative BIAS source.

And 5 V is more for TTL, so
perhaps that's been superceded by other topologies.

michael