CPU_LED lights up red immediately upon startup

By croozee
Mar 31, 2012
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  1. Specs:
    • Asus P8Z68-V Pro/Gen3 Motherboard
    • Intel i5 2500 CPU
    • Corsair H60 Liquid CPU Cooler


    Today I returned from a week-long vacation (haven't used it in a while), went to turn on my computer (I built it) and immediately upon startup, I noticed that the red CPU_LED was showing up. I reset my RAM, but that didn't help. Can anyone help me out?
  2. ComputerGuy55

    ComputerGuy55 TS Maniac Posts: 380   +8

    I assume from this that the computer does not boot properly, but require a bit more information.

    Does the computer Power on and stay on with the red light?
    Does it make any Beeps?
    Does anything show up on the monitor?
  3. Blkfx1

    Blkfx1 TS Evangelist Posts: 851   +201

    Make sure your CPU is seated properly and has no bent pins.
    Is your CPU getting the proper amont of power? Is the 4 or 8 pin cpu connector secure to the MOBO?
    Is all other connections secure?

    Assuming the computer worked fine before you left. Try resetting your CMOS that will clear your bios of any Overclocks or weird settings that could be causing problems.
  4. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,219   +157

    Do you recall seeing the error "A clock interrupt was not received on a secondary processor" and/or BCcode:101?
    Posting any error codes and mini dumps would be very helpful.
  5. captaincranky

    captaincranky TechSpot Addict Posts: 11,462   +1,760

    How exactly does one go about, "resetting their RAM..?:confused:

    It's just like those dad burned computer gremlins, to bend up the pins on your CPU, just because you're out of the house for a while....Or perhaps not!

    One very common reason for not restarting, is a bad PSU. They can sort of die in their sleep.
  6. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,219   +157

    Time out, or call an audible much like the Eagles do so well...or the Vikings :p

    Perhaps if one got it wet after midnight...or was that feed it?

    I wonder if the Op has a UPS or is plugged directly into the wall? Thunderstorm whilst you were on holiday?
  7. Doctor John

    Doctor John TS Enthusiast Posts: 204   +15

    I second the UPS/thunderstorm theory,
    also I would check the voltages out of the PSU with power on, see if you're actually getting 12V/5V with respect to earth, or if your PSU topped itself because you didn't take it with you!
  8. croozee

    croozee TS Rookie Topic Starter

    Yes, it powers on with the red light, but after about 15-30 seconds, it restarts itself without me pressing anything.






    How would I do this if the computer won't show anything on the monitor?

    Nothing shows up on the monitor.

    I just took it out and put it back in. I just call it "resetting my RAM".

    But if the PSU were dead, would it still turn on?

    I do not have a UPS.

    Sorry for the late reply. Been busy with work.
  9. captaincranky

    captaincranky TechSpot Addict Posts: 11,462   +1,760

    Oh. The more commonly used term is, "re-seating" the RAM. You can actually, "reset" RAM by turning off the PSU via the switch at the rear, and then holding the ON/OFF button in. This bleeds any residual current from the capacitors, and neutralizes any memory cells that might still be biased. (In theory at least. There's a bit of voodoo going on there).
    It might. All segments of a PSU do not have to fail at once for it to be bad. There are several voltages, positive and negative, that need to be present, or no "starty".

    With that said, I suffered a PF the other night on machines that were in standby. Consequently, I had to do the bleed power thingy I describes above, to get my XP box to boot. Before I cycled the PSU on and off physically, the CPU fan just come on and ran full blast, with no other sign of life from the computer. So, the "soft off" circuit in the PSU wasn't supplying any power to the CPU.

    Not saying that's your problem. Just moving the discussion along.

    I did a quick read through the whole thread, and it doesn't seem to mention whether or not your CPU fan is starting. Because that's a guaranteed overheat and shutdown in the time period you mention, if the cooler fan isn't running.

  10. ComputerGuy55

    ComputerGuy55 TS Maniac Posts: 380   +8

    Yeah. It could be an issue with PSU not supplying enough power. A lot of times when a computer powers on then powers itself off it is generally a power supply rail failing, and it powers down. Another could be like Captaincranky said and be overheating. the CPU could be overheating due to the fan not starting (as already stated) or the thermal paste could be dry and not transferring the heat properly.

    Resetting the CMOS is easy even though you don't see anything on the monitor, make sure the computer is off, unplug it. hold onto the side of the case (To be grounded) and take the CMOS battery out. After this, push and hold the power button for 15-30seconds and then put the battery back in. Plug it in, and power it on.

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