low voltage

R

Rudy Kube

Using a GA 7VT600 1394 MOBO. Thermaltake PSU. (480W Butterfly). Using
sisoftware plus other monitoring software to watch voltage & temps. (New
computer-temps are fine). The -12V & -5V are low. -4V to -6V for
the -12. -.03V to -3.0V for the -5V. Can these low voltages cause problems
such as a reboot or lose of video? I checked my other machines and these
voltages are almost right on the money? Bad PSU?? Also have a query into
thermaltake asking if it's normal. (I'm sure it's not????)

TIA
Rudy
 
D

Dave C.

Rudy Kube said:
Using a GA 7VT600 1394 MOBO. Thermaltake PSU. (480W Butterfly). Using
sisoftware plus other monitoring software to watch voltage & temps. (New
computer-temps are fine). The -12V & -5V are low. -4V to -6V for
the -12. -.03V to -3.0V for the -5V. Can these low voltages cause problems
such as a reboot or lose of video? I checked my other machines and these
voltages are almost right on the money? Bad PSU?? Also have a query into
thermaltake asking if it's normal. (I'm sure it's not????)

TIA
Rudy

Yes, low voltages CAN cause rebooting and/or loss of video. HOWEVER, never
rely on a software solution to report voltages accurately. IF you are
experiencing reboots and loss of video, you might want to replace the power
supply. But DO NOT replace the power supply because some software reports
voltages way off. Software can and does misreport voltages. -Dave
 
W

w_tom

Reporting software is not a problem. Your motherboard
'voltmeter' is not calibrated. It is a voltage monitor - not
to be confused with a voltage measurement device. Once that
motherboard voltage monitor is calibrated using a necessary
3.5 digit multimeter, then you set that monitor to alarm on a
number.

Is your power supply problematic? Don't even disconnect a
cable. It would only make an accurate answer more difficult.
Far more accurate answer is to leave everything as it and take
measurements with a 3.5 digit multimeter. Those numbers must
appear in upper 3/4 limits as provided in the procedures in:
"I think my power supply is dead" in alt.comp.hardware on 5
Feb 2004 at
http://www.tinyurl.com/2musa or
"Computer doesnt start at all" in alt.comp.hardware on 10
Jan 2004 at
http://tinyurl.com/2t69q

Lets return to your post. Voltages are low? What is low?
Without a specific number, you don't yet know. Furthermore,
motherboard monitor adds error. So we define a limit number.
Then we have error from the monitor. Should we move the limit
up because monitor might read high? IOW alarm on low voltage
and marginal (unknown) voltage. Or should we move limit down
by the error number from that monitor? IOW alarm only on
voltage definitely low and not alarm on voltage sufficient and
voltage marginal. Which one?

The amount of error in that motherboard monitor circuit is
typically large - and they typically don't provide that
important number. We have demonstrated here that the world is
ternary. Either voltage is sufficient, low, or undefined.
The less accurate a motherboard monitor circuit, then the
larger that undefined region.

Bottom line - get the 3.5 digit meter and don't even ask
why. Meter is a tool as important as a screwdriver and sold
even where screwdrivers are sold. Without numbers from that
meter, any answer will only be wild speculation. Without
numbers from that meter, you must resort to a despicable
diagnostic technique - shotgunning.
 

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