strange power-on action

I just built a new machine with the following components:
ASUS P5B-VM Intel G965 Micro ATX Motherboard
COOLER MASTER Real Power 450W Power Supply
COOLER MASTER Centurion 541 MicroATX Mini Tower Computer Case
CORSAIR XMS2 2GB (2 x 1GB) DDR2 800MHz Memory
Seagate Barracuda 7200.10 250GB 7200 RPM SATA 3.0Gb/s Hard Drive
LITE-ON 16X DVD±R DVD Burner W/ LightScribe and 5X DVD-RAM
Intel Core 2 Duo E6400 Processor

The system works fine, except for one curious thing...
When you hit the power button on the case, it turns on for 1 second, then turns off for about 5 seconds, and then turn back on and boots up.
When I click on "Turn off computer" in Windows XP (Home), the machine shuts down, stays off for 5 seconds, and then turns back on and boots up.
It's almost like the power off is acting like a reset. I double checked the connections from the case to the motherboard and things look to be connected correctly.

Any ideas what might be wrong?

Thanks in advance,
John
12 answers Last reply
More about strange power action
  1. erm thats pretty wierd i will give you that one hehe, faulty PSU gets my vote, got another PSU to try in it to find out?
    I take it you are using the onboard graphics since you didnt list a graphics card, take some time to describe any other strange behavior with the power, or anything else for that matter.
  2. Yes, I'm using the onboard graphics. As for any other strange behaviors...none. The machine works beautifully and it is extremely quiet and stable. CPU is running at around 40 deg. C. The loudest thing is the DVD drive when it spins up a disk.

    I'm building this machine for my father. I have an OCZ 700W PS on hand for the machine I'm planning to build for myself this Christmas. I tried it - same behavior. I also tried to rule out the case switch by shorting the power on pins on the motherboard to turn it on - again, same behavior. It seems like the issue lies with the motherboard. Could there be some strange BIOS or jumper setting that's causing this or does the board need to be RMA'd?
  3. Which company the mobo is? Try talking to technical dept about the issue. This sort of things usu happen when PSU is bad, but since you've switched it..........

    Anyhow try by minimum components' (CPU, mobo, RAM, PSU) method and see if it happens. If it doesn't, add some other component to isolate the problematic part.
  4. It couldnt hurt to to see if there is a BIOS revision for the board, read the patch notes for the revision and see if they adressed the issue, but since its not the PSU it sounds like its the mobo, if not the bios its just flat faulty, but since it doesnt seem to hurt anything just run it until it dies then RMA it -=P
  5. have u try shutting it down by pressing the power button itself instead of Start->Shut down?
  6. Yes, I flashed a new BIOS last night. No change. Hopefully Newegg will cross ship a new motherboard.
  7. I gave it a try, and yes, it shuts down and stays down. 8O
    Not sure what that means. I don't think this is the intended behavior. I also don't think that's the appropriate way to shut windows down. However, it is another workaround in the meantime. Maybe Asus can give me a clue?
  8. Quote:
    I gave it a try, and yes, it shuts down and stays down. 8O
    Not sure what that means. I don't think this is the intended behavior. I also don't think that's the appropriate way to shut windows down. However, it is another workaround in the meantime. Maybe Asus can give me a clue?


    Look in the BIOS and make sure Wake on LAN is disabled. This causes weird behaviors such as yours.
  9. Yep, I thought of that. I have all of that stuff turned off. BIOS settings in the power menu as follows:
    Suspend mode - auto
    Repost video on S3 resume - disabled
    ACPI 2.0 support - disabled
    ACPI APIC support - enabled
    Restore on AC power loss - power off
    Power on by RTC alarm - disabled
    Power on by external modems - disabled
    Power on by PCI devices - disabled
    Power on by PCIE devices - disabled
    Power on by PS/2 keyboard - disabled
    Power on by PS/2 mouse - disabled
  10. I cleared the RTC RAM and all is well. Some strange data must have been stuck in the CMOS memory. :D
  11. Quote:
    I cleared the RTC RAM and all is well. Some strange data must have been stuck in the CMOS memory. :D


    WoW! Never would have tried it by myself! Congrats!
    I had the same problem and clearing the RTC RAM fixed it.
    Thanks a lot jdmessina.
  12. Handy post, might try that on a couple of ScktA Asus boards I have used for people. Both of these boards power the fans for a second or so, shutdown and then boot. Thought it was weird but according to the website it is normal for these boards, at least they power down properly though.
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