If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
PSU Failing or what?
|
#2
|
|||
|
|||
On Tue, 11 Jan 2005 19:48:35 -0500, "
DNC_TN@ wrote: Here are some readings... VCOREA=1.70V VINRO=1.70V +3.3v = 3.44v +5v=5.08V +12V=11.67V -12V=-11.88V -5V=-4.62V What does this mean? a failing psu? also these values fluctuate wildly especially the +/-5 and the neg12V one does. My comp also does a reboot for unknown reasons on occasions. thanks, +12V reading looks right for a motherboard sensor reading, but if it were from a multimeter reading at power connector, more likely then a sign of insufficient 12V rail capacity. It's not surprising that negative values are fluctuating if unloaded, which is probably the case. What CPU do you have that has 1.7V Vcore? Perhaps it's overclocked (therefore overvolted intentionally)? Sometimes a mobo's vcore will be a little high on a CPU with 1.65V default vcore, but generally not a whole .05V higher. Even so, too high a vcore shouldn't be rebooting system unless CPU is overheating. Rebooting could simply be windows errors, disable the windows reboot on error setting (Google searching will find details on doing that). If it seems more related to power or temp, more closely monitor status of those readings while reproducing events causing reboot. |
#3
|
|||
|
|||
The 3.3 volts is marginally high. Just under the limit of
being too high and therefore suspect. 12 volts is just above the limit. Again, you did not say what measured voltage - what hardware. Therefore these conclusions are still invalid. But from that 12 volt number and if using a 3.5 digit multimeter, then I would investigate further for too much ripple voltage on that supply - a slowly failing internal part. Again, it sounds like you thought motherboard readings were reliable. Wrong. Requirement of a 3.5 digit multimeter is the cheapest method possible to measure voltage with any reliability. The 3.5 digit meter then calibrates motherboard voltage monitor. -5 also does not look good. But -5 typically is not used for anything important. Where is +5 VSB? Numbers for that important voltage were not provided. Get the meter. Some examples of how to measure important voltages: "Computer doesnt start at all" in alt.comp.hardware on 10 Jan 2004 at http://tinyurl.com/2t69q and "I think my power supply is dead" in alt.comp.hardware on 5 Feb 2004 at http://tinyurl.com/yvbw9 " wrote: Here are some readings... VCOREA=1.70V VINRO=1.70V +3.3v = 3.44v +5v=5.08V +12V=11.67V -12V=-11.88V -5V=-4.62V What does this mean? a failing psu? also these values fluctuate wildly especially the +/-5 and the neg12V one does. My comp also does a reboot for unknown reasons on occasions. thanks, |
#4
|
|||
|
|||
w_tom wrote:
The 3.3 volts is marginally high. Just under the limit of being too high and therefore suspect. 12 volts is just above the limit. His 12 volt rail, at only 2.75% down, is well within limits, and not 'above' them. Again, you did not say what measured voltage - what hardware. Therefore these conclusions are still invalid. But from that 12 volt number and if using a 3.5 digit multimeter, then I would investigate further for too much ripple voltage on that supply - a slowly failing internal part. Again, it sounds like you thought motherboard readings were reliable. Wrong. Requirement of a 3.5 digit multimeter is the cheapest method possible to measure voltage with any reliability. The 3.5 digit meter then calibrates motherboard voltage monitor. -5 also does not look good. But -5 typically is not used for anything important. Where is +5 VSB? Numbers for that important voltage were not provided. Get the meter. Some examples of how to measure important voltages: "Computer doesnt start at all" in alt.comp.hardware on 10 Jan 2004 at http://tinyurl.com/2t69q and "I think my power supply is dead" in alt.comp.hardware on 5 Feb 2004 at http://tinyurl.com/yvbw9 " wrote: Here are some readings... VCOREA=1.70V VINRO=1.70V +3.3v = 3.44v +5v=5.08V +12V=11.67V -12V=-11.88V -5V=-4.62V What does this mean? a failing psu? also these values fluctuate wildly especially the +/-5 and the neg12V one does. My comp also does a reboot for unknown reasons on occasions. thanks, |
#5
|
|||
|
|||
Limits for 12 volt supply: 11.4 V to 12.6 V
His voltage: 11.67V. Therefore as previously posted: 12 volts is just above the limit. When taking voltage with a 3.5 digit multimeter, the readings must be in the upper three quarters of those limits. Voltages in the lowest quarter may be due to excessive ripple voltage. This is a failure that has not yet happened. Multimeters cannot measure ripple voltages. Therefore a voltage in the lower quarter of those limits suggests further study may be required using other equipment. His 12 volt readings may be an indication of excessive ripple voltage that will only get worse in the future. But more important, we don't know what was used to measure these voltages. If measured using the motherboard monitor, then the readings are not reliable. He has three problems. 3.3 is suspiciously high. 12 volts might be questionable. Source of these numbers is highly suspect. It may be a good supply. But we don't know yet from numbers as provided. David Maynard wrote: His 12 volt rail, at only 2.75% down, is well within limits, and not 'above' them. |
#6
|
|||
|
|||
On Thu, 13 Jan 2005 14:36:18 -0500, w_tom
wrote: Limits for 12 volt supply: 11.4 V to 12.6 V His voltage: 11.67V. Therefore as previously posted: 12 volts is just above the limit. When taking voltage with a 3.5 digit multimeter, the readings must be in the upper three quarters of those limits. Voltages in the lowest quarter may be due to excessive ripple voltage. This is a failure that has not yet happened. Multimeters cannot measure ripple voltages. Therefore a voltage in the lower quarter of those limits suggests further study may be required using other equipment. His 12 volt readings may be an indication of excessive ripple voltage that will only get worse in the future. But more important, we don't know what was used to measure these voltages. If measured using the motherboard monitor, then the readings are not reliable. He has three problems. 3.3 is suspiciously high. 12 volts might be questionable. Source of these numbers is highly suspect. It may be a good supply. But we don't know yet from numbers as provided. David Maynard wrote: His 12 volt rail, at only 2.75% down, is well within limits, and not 'above' them. Primarily, OP omitted basic critical details of the motherboard and power supply. We have no reference of power distribution for the system. I agree that 11.67V is in-spec BUT that a motherboard reading cannot be relied upon, in general most motherboards do read a lower than actual 12V level when PSU output is spot-on 12.0V. Multimeter readings at power supply connector to motherboard are crucial for 12V reading. Having written that, if the multimeter reading is at 11.67, it is a sign that the power supply is of insufficient capacity, else not appropriate for the system (typically using a system with 12V power for CPU but not an ATX v2.03 power supply, so the PSU has little to no 12V feedback weighting for regulation, rather it's regulating based mostly or entirely upon 5V reading, which would coincide with voltage readings reported. Even so, CPU VRM circuit will remain stable far below 11.67V, most would be OK below 10V, but this tells nothing of the power supply's other rails. |
#7
|
|||
|
|||
When using a digital voltmeter, voltages in the bottom
quarter of voltage limits are undefined. A ternary world where we have good, bad, and undefined conditions. It may be good or it could also be bad - therefore undefined. That voltage reading is 11.67. Number is within voltage limits but is in bottom quarter. Now that could be 11.67 volts with a ripple voltage of 50 mv. Or that could be a voltage that varies between 11.3 and 11.7 because the 12 volt output has too much ripple voltage - 400 millivolts. Voltage is still undefined. A meter often tends to read the upper voltage of that ripple wave. Therefore that 11.67 volts really might be 11.5 with excessive (out of spec) ripple voltage. IOW voltage dropping repeatedly to 11.3 volts. IOW we don't know if that 12 volts is good because at 11.67 volts, it is in the bottom 1/4 of those limits AND because multimeters don't always read RMS; cannot read higher frequency ripple voltages. Again, that 3.3 volts is in limits but suspiciously high. And that 12 volts is also in a region of suspicion. Yes the system is often very tolerant of bad 12 V DC. But a system is often less tolerant of high ripple voltages. 11.67 may be a symptom of excessive ripple voltage. kony wrote: On Thu, 13 Jan 2005 14:36:18 -0500, w_tom wrote: Limits for 12 volt supply: 11.4 V to 12.6 V His voltage: 11.67V. Therefore as previously posted: 12 volts is just above the limit. When taking voltage with a 3.5 digit multimeter, the readings must be in the upper three quarters of those limits. Voltages in the lowest quarter may be due to excessive ripple voltage. This is a failure that has not yet happened. Multimeters cannot measure ripple voltages. Therefore a voltage in the lower quarter of those limits suggests further study may be required using other equipment. ... Primarily, OP omitted basic critical details of the motherboard and power supply. We have no reference of power distribution for the system. I agree that 11.67V is in-spec BUT that a motherboard reading cannot be relied upon, in general most motherboards do read a lower than actual 12V level when PSU output is spot-on 12.0V. Multimeter readings at power supply connector to motherboard are crucial for 12V reading. Having written that, if the multimeter reading is at 11.67, it is a sign that the power supply is of insufficient capacity, else not appropriate for the system (typically using a system with 12V power for CPU but not an ATX v2.03 power supply, so the PSU has little to no 12V feedback weighting for regulation, rather it's regulating based mostly or entirely upon 5V reading, which would coincide with voltage readings reported. Even so, CPU VRM circuit will remain stable far below 11.67V, most would be OK below 10V, but this tells nothing of the power supply's other rails. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
hard drive failing? | Luis ORTEGA | General | 4 | October 20th 04 10:35 PM |
Failing 1400 MHz AMD system | Russell Silva | General | 2 | August 2nd 04 12:09 AM |
SOYO K7VTA Pro Box - Something Failing, Can't Diagnose | Don_B | Homebuilt PC's | 4 | February 16th 04 12:10 AM |
Hard Drive Failing?? | Just Wondering | General | 0 | October 19th 03 09:08 PM |
Possible Hard Drive Failing? | Nick | General | 1 | July 27th 03 09:06 PM |