Help With Finding Why Voltage Changes

[zachaller]

My voltages on my Vcore and +12 are pretty jumpy I dont know what could be causeing this i have a 400W Antec SL400. Could it be the wall outlit it is kinda old has no 3rd prong hole could it be the breaker or the mother board i need help trying to figure this out i really would rather not send back MB but if i have to i have to so what are some possibilities that cause this.

[KnownKiller]

Take a look at my post over HERE (http://www.xtremesystems.org/forums/showthread.php?s=&threadid=17182)

I have the same probs as you with the 12v line on both an old Antec true power 550 and a Brand new never used Antec True control 550 watt..

I'd advise to taek your M/B out and check the back for damage like i have HERE (http://www.xtremesystems.org/forums/showthread.php?s=&threadid=17095) I'm not sure if the damage is from a bad VDD mod i did to the board or not.. Same thing happend to a new M/B and i didnt even touch the board but it did have the same Antec True Power P/S.

[zachaller]

I will check the MB did you have any VCore Voltages jumps


Also I have tried two diffrent PSU a 300w Antect smart power and a 400w

[KnownKiller]

I'm not sure.. but dont think so.. Only thing i noticed using hardware doctor while the board was runing was the 12v line was jumping from 11.98-11.85v which it never did before.. That was with no load.. You really cant trust the voltage monitoring software.. Only way to be sure is to use a digital multimeter on the molex.. test the 12v and the 5v.. Only way to test the 3.3 line is from the atx connector.

[zachaller]

I Really dont know much about the testing and electricle part but i am beging to see it is really important and i am starting to learn alot how would i go about testing it and also could it be anything else beside the MB

[KnownKiller]

I found out that you need to have the P/S in the system and runing to get an accurate reading off the molex connector.. Once i did this insted of having nothing on the P/S other then a fan i got stable readings that didnt budge.. I dont know if you were doing the same or not.. But if your are all over the place while runign the system then i'd say its going bad or your runing too much stuff of the P/S but i'd doubt that.

Trust the reading off the molex connector. If its fine on there then the prob could lie with your motherboard not letting the right power flow threw the system.

[Southpaw]

The lines on my SL400 are very stable...PS seems to run a little warm, but checking voltages using a DMM shows it as OK

[JKeefe]

Originally posted by zachaller
Could it be the wall outlit it is kinda old has no 3rd prong holeThe only reason the PSU cage, the metal parts of your case (which connect to points on the motherboard), and the ground lines in all of the system's wires are grounded is because everything conducts to the power supply, and that is connected to the third prong and runs into your wall. If it doesn't run into your wall, your computer is not grounded (unless you grounded it some other way) and that is bad. Get a two-to-three prong converter and attach the grounding wire to the screw on your power outlet.

[zachaller]

I am sorryi havn't replayied in some time had the computer down i have not tried the multimeter yet but i know it is low because the computet is not stable and when i up the voltages in bios it works but they are still jumpy. About the grounding i ran an exstension cord out to one of the three prong outlets in my house till i get the one in my room changed dose this work for grouding it but i did not get any stable voltages with it.

[JKeefe]

Originally posted by zachaller
About the grounding i ran an exstension cord out to one of the three prong outlets in my house till i get the one in my room changed dose this work for grouding it but i did not get any stable voltages with it. Yes, now your system is grounded. It may not directly help the voltages but it is still vital to the correct operation of your computer.