12V rail --> 22.44V in Speedfan?!?! Abrupt shutdowns...

Hi all, any advice would be greatly appreciated...

My PC has been experiencing abrupt shutdowns (every few minutes now), followed by an automatic reboot.
I just installed PCAlert4 (came with my MSI mobo) and Speedfan and they both say my 12V rail is 22.44V !?!?!

Question: Is my power supply defective?? Is there an easy way to test it with a voltmeter?

Some more info:

1. Fresh (new HDD partition) install of Windows XP w/ SP2 --->abrupt shutdown experienced even before installation of drivers, AVG etc
2. Memory has passed testing using memtest on another PC.
3. I have done cleaning of interior, re-seating of memory, other PCI cards.
4. A few months earlier, my PC would have a hard time booting (does not even get into BIOS memory count and no "beep").
I usually fixed this by cleaning the interior, pressing the on-off switch a dozen times while powered off, and then it would work again.
This happened almost every other day for 1-2 months. Problem seems gone, now I just experience abrupt shutdowns.
5. A few days ago, I noticed my CPU temp jumped to 77-80C (according to BIOS) after an abrupt shutdown,
it used to be 60-69ish C when it was new and with the stock fan.
I then bought a Coolermaster Hyper 212 plus yesterday and temperature is now around 31C-40C amazing!!.
6. PC doesn't seem to go into abrupt shutdown/reboot if only in the BIOS menu
7. All the components in use are months old...maybe even over a year, except for the new cooler for the CPU.
8. PC details:

E4400 CPU w/ MSI P965NeoF V2 mobo
2pcs 2GB Kingston DDRII 800 Ram
Palit 4850 Video Card
Currently only an 80GB IDE HDD (boot drive) and DVDrw Drive are connected --> still I have abrupt shutdowns.
PSU: Antec Earthwatts 500
Windows XP SP2

Question: Is it possible my mobo is damaged? or my CPU has been damaged?

PS. I am using my other desktop PC to send this. The problem PC won't let me finish.
Any advice and tips (as painless as possible) would be much appreciated. I have spent too much time on this already.
Thank you in advance.

11 answers Last reply
More about rail speedfan abrupt shutdowns
  1. Your CPU is not likely to be damaged because that massive voltage will have to go through your motherboard first. Swap your PSU and see if problem persists.
  2. You can check the 12 volts with a multimeter, connect the meter on the volts range between the black and yellow wires. I would suggest that you change the power supply anyway as it is the most likely cause of the shut downs.
  3. Thanks for the quick replies.

    I tried using my sanwa digital multimeter to measure one of the spare power plugs (yellow and black). It gave me a fluctuating 12V reading between 11.98 to 12.20 At least it wasn't 24.44V (not sure now why the software reports it that way). The reading is usually between 12.16V to 12.19V What I observed was that when it did an abrupt shutdown (yeah I waited for it), it would quickly go from 12V down to about 3V..then 1V...then 0.5V then back to 12V all in about 6 seconds, then the reboot, theres a beep somewhere in there too. I tried to do a normal windows restart, to compare and the power never went below 12V. For the record, if I end up buying a new PSU, this would now be the second Antec Earthwatts 500 I had to replace. First time, it was DOA from the shop, now about a year later this unit...sigh. I am now all the way ENERMAX. My other unit has been running for 3-4 years on an ENERMAX, solid! Sometimes I leave it on for 2weeks straight 24x7.

    Thanks again.
  4. The normal problem is the PSU - But there are other possibilities.
    Your +12 V readings are good and the decrease in voltage ( to 3 then to 1)are normal. Caused by capacitors. Remember that a voltmeter will not display a spike in voltage. Also measure your +5 volt, measure at molex connector - red to black. Must be above 4.75 V.

    Other possibilities could be hardware/software confict. Normally windows will display an error message. HOWEVER, it may be so quick that it is not displayed.
    Need to go into system and disable automatic reboot upon error.

    Goto Mycomputer - Properties - click advanced tab
    Select Startup and recovery - settings - uncheck (clear) Automatic restart

    Try CPUID HWMonitor .
  5. Added - With CPUID HWMonitor, Not the Min/Max values at idle, then run a program that loads your system, ie Furmark (Load +12 V), or Prime 95 to load proc.

    If a voltage is way outside of it's value - it's a "Borcked" value and is invalid. ie if +12 reads +3 - computer would not be on. +22 for +12 = Fried components

    The +3.3 is another voltage to look at. If software reading looks good, it's probably OK. This is harder to measure with a DVM. Nead to measure it on the 20/24 pin Motherboard connector. I use straight pin (wife's sewing kit).


    For walsh155 - it's a good idea to read ALL of the post, not just orginal. You would have noted that he already used a DVM and that the +12V was within tolerence.
  6. @OP: Are you BSODing or just complete shutdown? Could be RAM problems if you are BSODing. Download and test RAM with Memtest86+.
  7. Hi all, thanks for the replies again.

    I have tried:

    1. My Computer -> Properties -> Advanced -> Startup & Recovery Settings -> Uncheck Automatically Restart. This did not prevent the PC from the abrupt shutdowns -> reboot.

    2. Control Panel -> Administrative Tools -> Event Viewer -> check logs. Nothing glaring or seemingly relevant was reported.

    3. No, there are no BSODs

    4. Yes, I have checked the RAM, by moving them to a different PC and running Memtest. They passsed.

    5. CPUID Hardware Monitor (wow, this is cool) does not even show my 12V readings. Everything else looks fine. I tried the CPUID on another machine, and it gave 12V readings. So if the sensor is unreadable (defective?), what sensor is it trying to read, the sensor on the mobo or the PSU? I am not too familiar with how the software works.

    I better send this now before I get an abrupt shutdown.
  8. I will try swapping out the PSU next...man, what a pain that is
  9. I should add CPUID says my sensor is "Fintek F71882F" If this sensor is on the mobo, then is the mobo damaged too?
  10. One more thing, CPUID says my:

    3.3V = 3.31V to 3.33V
    Vcore = 1.22V to 1.37V
    5V = 5.09V

    Core#0 = 38C to 49C
    Core#1 = 39C to 54C

    TMPIN0 = 29C to 37C
    TMPIN1 = 34C to 37C
    TMPIN2 = 76C to 77C <-- This worries me a bit, what is this?

    On another PC, TMPIN2 is between 4C to 47C.

    Thanks again.

    I tried swapping out the PSU...problem did not go away.

    I then tried swapping out the Video card...problem did not go away.

    This leaves only the mobo and the CPU...so I tried swapping out the CPU, seems that solved the problem, not a single abrupt shutdown/reboot in about 3 hours (and counting) of gaming now compaired to about 3-5 minutes before.

    CPU must have been damaged somehow.

    Thanks to all for the advice.
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