Random power offs...-5v? Help

Asus P4C800 Deluxe
P4C 3.0gHz
1024 Kingston ValueRam (2x512)
80gb Seagate 7200
250gb Maxtor 7200
2x Hard Drive fan
ATI 9600Pro 128mb
Sound Blaster Audigy 2 ZS platinum

My computer randomly shuts off, and has been doing this for the past few years. I've tried replacing RAM, video card, heatsink, psu, but nothing seems to fix it.

My friend sent me this program to monitor temperatures, and my hard drives were at 50+ degrees. So i bought some hard drive fans, being sure that this was the reason for the crashes.

After a few days the voltage for -5v went from not being used to being red and at -5.95v
i moved around some of the 4pin power cables in a trial and error and the -5v went back to not being used. It was stable for about a day, then powered off randomly like usual and the -5v went back to being red

im also not sure what the aux means

sorry if this isnt descriptive enough i figured it would be a psu problem so i posted here

My -5v is apparently in the red zone at -5.95v
23 answers Last reply
More about random power offs help
  1. As far as I know, the -5V and -12V rails are rarely used any more. In fact there are PSUs that dont even have them I think. The AUX could be the +5VSB (stand by) rail which is needed if you set your computer to the Suspend-To-RAM setting for standby. What is the default voltage for your cpu?
  2. yeah i thought -5v wasnt used anymore
    which makes it so weird that sometimes its red and other times its not in use

    and the default voltage of my cpu is 1.5v
  3. also, if it helps
    my psu is an AOPEN 350w (+3.3v and +5v=120w max)

  4. So a vcore of 1.55V is not so bad, it could simply be a wrong reading by the motherboard. My old a64 3000 supposedly has a vcore of 1.56-1.59V when its default is 1.5V. It could be right and the motherboard is terrible at regulating the voltage, but usually you should take the readings with a grain of salt.

    If you have another psu lying around you could stick that in and see if the same thing happens (the random shutdowns). If you still have the shutdowns and the error readings continue to appear then its likely the motherboard is reading wrong because the two psus should not have the same problem, but it is possible. If the shutdowns disappear but the errors dont then the motherboard is almost definitely reading wrong.
  5. A 350W psu with a max output of 120W? Oh, of course, that doesnt include the +12V rail :oops: . What is the model number for your psu coz its easier to find out info on it that way as Aopen probably make more than one type of 350W psu?

    EDIT: There are in fact 7 350W psus by Aopen :?

    EDIT2: Does it have a large 120mm fan on the bottom or a single 80mm on the back facing out of the case? This would cut down the list alot if you cant find the model number.
  6. I once had a generic 400W psu running my 9800 pro and a64 3000+. Lasted around 2 years before I replaced it, and it was still working whan I did, I jsut wanted to be on the safe side...
  7. well this is actually my 3rd power supply
    but both were installed by the guy who made my computer so i dont have any extras

    and ive had this problem for the longest time and i realize how hard it is to pinpoint why the computer is crashing (not rebooting) its as if someone pulls the plug
    and it is completely random, my computer can be idle without running any programs or during a game, or during a movie...totally random

    the model number is Z350-08ATA

    and nothing in my events that indicates a reason to crash either

    3 years of this crashing when will it end
  8. You said the computer powered off not crashed, make your mind up since if its just crashing then it could be software. Anyway I found the specs on this thing and am looking at them now.
  9. Ok well according to the specs sheet from Aopen there is no -5V rail. But there is a -12V rail.
  10. Quote:
    its not the psu.

    You dont know that, but its definitely possible that its not. But if you look at the thing, it looks like a cheap psu with the typical stamped out fan grill on the back.
  11. I realise that, but as I said the psu spec sheet says there is no -5V rail, or rather doesnt have any info on it like max/min load etc. Also like I said the mobo could have faulty sensors, I mean, if it fluctuated that much he should have dead components by now.

    EDIT: I wondered what was up with your last post, since you quoted but said nothing. At least you fixed it :P
  12. it powers off not crashes...its not software related
    i reformatted countless times with xp and 2000 and even linux...still crashed

    and im pretty sure it doesnt have a -5v rail....but why would it tell me i do after powering off? the system is stable when i get a proper reading showing that it doesnt exist
  13. if it was my mobo...would i need to replace it completely?
  14. my bios shows the same readings for the voltages my psu is SUPPOSED to have but it doesnt even show a reading for -5v
    neither does asus pc probe
  15. Try disabling the sensor for that rail in the BIOS, it could be the mobo is detecting an overvoltage that may not be occuring and shutting down. If it still shuts down then there is definitely something wrong with the psu or motherboard power regulators.

    EDIT: Now you tell me... :roll: :wink:
  16. Try a different program and see if it gives a different reading. ASUS Probe is so full of flaws.
  17. i disabled the 5v monitor in bios
    and hmonitor (the program im using because i agree, asus probe blows)
    still gives me the same readings for 5 and -5

    the guy who installed the psu is a total moron and would just tell me something else is wrong and try to get more money...he said my last psu was the crash problem, and i trusted that and it still crashes with his "superior" psu :S
  18. Did he actually call it superior? If so then I laugh in his face! :lol: :lol: :lol: :lol: :lol: :lol: :lol:

    Its not a great psu, you should probably buy a new one anyway. And dont ever trust morons, because theyre morons.

    EDIT: Where exactly did you get it from?
  19. We're getting off-topic here. You said:
    "I've tried replacing RAM, video card, heatsink, psu..."

    It's not your RAM, video card or your PSU.

    Your CPU temps are normal, so it's not your heatsink.

    #1 - Try disabling the -5v sensor in BIOS.
    #2 - Check North bridge controller for thermal paste
    #3 - Consider replacing the motherboard (may have internal shorts)
    #4 - Failing that, your CPU may be defective
  20. well im hopefully getting a brand new rig soon anyway
    so im trying to spend as little as possible on this one
    but it would still be great if i could fix it
    if its in need of a new mobo or cpu its not worth it in the end when i have my new rig

    but if it was something with the psu that i could change to make it stable then i might as well

    the only problem i knew of that would lead to a crash was the red readouts in my monitor program
    and i wasnt too sure what they meant to begin with

    ill ask a few friends if they have any psu's lying around to do a quick swap

    if this just cant be fixed then time for that new rig
  21. nope nothing wrong in my events
  22. can you suggest a good cpu stress tester?
    ill get memtest and that seagate program and report back
  23. I own one of those 430W thermaltakes (the TR2) and I would happily lend it to you if you lived in Sydney, Australia, and since its unlikely that you do, your going to have to look elsewhere :wink:
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