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Seeker
Guest
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 Posted: Wed Feb 15, 2006 12:18 pm Post subject: L7S7A2 - low voltages reported |
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I just noticed that my L7S7A2 gives the following voltage readings
(from Speedfan, bios readings are similar):
+3.3V: 1.34V
+5V: 2.45V
+12V: 7.17V
-12V: -6.11V
-5V: -4.00V
Also, they vary wildly. My system has a problem when starting up, it
restarts until the PSU is heated (I presume) but after that it can
run for days without a restart and the cpu at 100%.
Is this a problem with the mobo sensors or should I change my PSU? |
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JimL
Guest
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| Posted: Wed Feb 15, 2006 6:32 pm Post subject: Re: L7S7A2 - low voltages reported |
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On Wed, 15 Feb 2006 12:18:47 +0000 (UTC), Seeker
<seeker.10.psymaster@spamgourmet.com> wrote:
| Quote: | I just noticed that my L7S7A2 gives the following voltage readings
(from Speedfan, bios readings are similar):
+3.3V: 1.34V
+5V: 2.45V
+12V: 7.17V
-12V: -6.11V
-5V: -4.00V
Also, they vary wildly. My system has a problem when starting up, it
restarts until the PSU is heated (I presume) but after that it can
run for days without a restart and the cpu at 100%.
Is this a problem with the mobo sensors or should I change my PSU?
|
Sure. Definitely a problem with the sensors. A digital multimeter
can be had for $5 from harbor freight.
The machine will not run at those voltages. |
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Seeker
Guest
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| Posted: Wed Feb 15, 2006 8:10 pm Post subject: Re: L7S7A2 - low voltages reported |
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JimL <jiml@hal-pc.org> wrote in
news:39q6v1pnm4tjlimirt3teqidlur1ic5mhf@4ax.com:
| Quote: |
On Wed, 15 Feb 2006 12:18:47 +0000 (UTC), Seeker
seeker.10.psymaster@spamgourmet.com> wrote:
I just noticed that my L7S7A2 gives the following voltage
readings (from Speedfan, bios readings are similar):
+3.3V: 1.34V
+5V: 2.45V
+12V: 7.17V
-12V: -6.11V
-5V: -4.00V
Also, they vary wildly. My system has a problem when starting
up, it restarts until the PSU is heated (I presume) but after
that it can run for days without a restart and the cpu at 100%.
Is this a problem with the mobo sensors or should I change my
PSU?
Sure. Definitely a problem with the sensors. A digital
multimeter
can be had for $5 from harbor freight.
The machine will not run at those voltages.
|
I will get a multimeter to check them out, but I was curious
because the readings do not exceed the nominal voltages... |
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JimL
Guest
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| Posted: Wed Feb 15, 2006 11:32 pm Post subject: Re: L7S7A2 - low voltages reported |
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On Wed, 15 Feb 2006 20:10:20 +0000 (UTC), Seeker
<seeker.10.psymaster@spamgourmet.com> wrote:
| Quote: | JimL <jiml@hal-pc.org> wrote in
news:39q6v1pnm4tjlimirt3teqidlur1ic5mhf@4ax.com:
On Wed, 15 Feb 2006 12:18:47 +0000 (UTC), Seeker
seeker.10.psymaster@spamgourmet.com> wrote:
I just noticed that my L7S7A2 gives the following voltage
readings (from Speedfan, bios readings are similar):
+3.3V: 1.34V
+5V: 2.45V
+12V: 7.17V
-12V: -6.11V
-5V: -4.00V
Also, they vary wildly. My system has a problem when starting
up, it restarts until the PSU is heated (I presume) but after
that it can run for days without a restart and the cpu at 100%.
Is this a problem with the mobo sensors or should I change my
PSU?
Sure. Definitely a problem with the sensors. A digital
multimeter
can be had for $5 from harbor freight.
The machine will not run at those voltages.
I will get a multimeter to check them out, but I was curious
because the readings do not exceed the nominal voltages...
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Keep looking for motherboard monitor programs.
Some of them work and some don't. Even some versions may work and
others wont. Pretty common to find one that doesn't work.
Start here:
http://www.pcworld.com/downloads/file_description/0,fid,7309,RSS,RSS,00.asp |
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Seeker
Guest
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| Posted: Wed Feb 15, 2006 11:44 pm Post subject: Re: L7S7A2 - low voltages reported |
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JimL <jiml@hal-pc.org> wrote in
news:g1b7v19p4us4ib8c3vh58q6hrnko12kk26@4ax.com:
I installed MBM, it's a great program, but it gives the same readings
as Speedfan and the BIOS. |
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Paul
Guest
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| Posted: Thu Feb 16, 2006 10:31 am Post subject: Re: L7S7A2 - low voltages reported |
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In article <Xns976C11B6D85B5irhlnvawd@193.92.150.76>, Seeker
<seeker.10.psymaster@spamgourmet.com> wrote:
| Quote: | JimL <jiml@hal-pc.org> wrote in
news:g1b7v19p4us4ib8c3vh58q6hrnko12kk26@4ax.com:
Keep looking for motherboard monitor programs.
Some of them work and some don't. Even some versions may work
and
others wont. Pretty common to find one that doesn't work.
Start here:
http://www.pcworld.com/downloads/file_description/0,fid,7309,RSS,
RSS,00.asp
I installed MBM, it's a great program, but it gives the same readings
as Speedfan and the BIOS.
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A little Googling turned up this. Customization for MBM5 on L7S7A2.
http://groups.google.ca/group/alt.comp.hardware.homebuilt/browse_frm/thread/fb7405ab5cfebdac/20bd659ab28f2878
PDF page 98 of this doc has some info on the registers.
PDF page 103 has some info on external scaling resistors.
http://www.iteusa.com/product_info/file/pc/IT8705F_V.0.4.1.pdf
As noted in the above Google thread, voltage scaling of a monitor
chip is determined by external resistors. When a voltage to
be monitored is smaller than full scale (like 4.096 volts),
then no resistor scaling is needed. For other voltages, external
resistors may be needed to shrink the voltage so it fits within
the measurement range of the ADC. The scaling effect is what the
MBM customization is trying to account for above. (And if a
motherboard maker does something non-standard when choosing
the resistors, then all the free monitoring programs will
read out the wrong voltage value.)
You will likely find, that raw readings from a monitor chip,
will jump around by the stated quanta in that Google thread.
The ADC has a resolution of 0.016V and so the basic unscaled
readings will jump around by that much. Monitoring programs
will probably take a "running average" of a series of readings,
which effectively filters out the "noise" or reading to
reading variation from the monitor chip. However, if the
voltage being monitored really is noisy, you will still see
the final voltage value flying around. But the difference
between readings can no longer be traced to the step size
(0.016V) of the monitor chip, because the "running average"
will tend to hide it.
In other words, with no running average in place, there will
be a visible measurement noise from sample to sample. Once
a monitoring program takes the running average of a series
of readings, some of that noise will be filtered out, making
the chip look better than it really is. The disadvantage of
using too large a running average, is it takes a long time
to respond to voltage changes.
HTH,
Paul |
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Seeker
Guest
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| Posted: Fri Feb 17, 2006 1:55 pm Post subject: Re: L7S7A2 - low voltages reported |
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I got a mutlimeter and measured the 12V and 5V rails, they look ok.
If my psu is insufficient for my system, what should I expect? Is it
possible that the system will run without crashing but with lower
performance? |
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WM
Guest
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| Posted: Mon Feb 20, 2006 3:32 am Post subject: Re: L7S7A2 - low voltages reported |
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On Fri, 17 Feb 2006 13:55:01 +0000 (UTC), Seeker
<seeker.10.psymaster@spamgourmet.com> wrote:
| Quote: | I got a mutlimeter and measured the 12V and 5V rails, they look ok.
If my psu is insufficient for my system, what should I expect? Is it
possible that the system will run without crashing but with lower
performance?
|
No. |
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