PSU fan and light stay on permanently after shutdown. A7V333 with new Topopwer PSU.

Discussion in 'Asus' started by Darren, Jan 25, 2005.

  1. Darren

    Darren Guest


    I've recently replaced my PSU to a Topower TOP-500P5.

    The PSU has cooling after shutdown for about 3 minutes I think, according to
    the spec's. (Called ECASO.)

    The PSU has a light too and when I went to bed after installation and
    Windows 2K shutdown, that blue PSU light stayed on for an hour and the PSU
    fan continued to turn slow. I switched the PSU off manually.

    I also note that my motherboard has an LED witch stays on after I shut the
    PC down in Win2K.

    I have BIOS wakeup features disabled.

    The PC boots okay with the power button.

    Does my Asus a7v333 have a bios setting or jumper I've missed and am I
    really shutting down into some sort of standy mode?

    I really would like to choose shutdown and after 3 mins of cooling etc. the
    PSU and it's lights and fans do what I do, switch off and go to sleep.


    Darren, Jan 25, 2005
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  2. I would have expected the fan to stop.
    However the motherboard LED is normal. ATX PSU's, basically have two power
    supplies in the one case. The 'main' supply, and a seperate low current 5v
    supply (the rating varies, but normally just a couple of amps at 5v max).
    ATX motherboards use the power from this, to run the actual control
    circuitry to switch on/off the main supply, and keep circuitry alive, that
    can wake up the machine. Hence (for instance), if you have options in the
    CMOS setup to enable wake-up on LAN, keyboard, and USB, these components
    will be powered even when the main supply is switched off. Even if all
    these options are disabled in the CMOS, power will still be going to the
    motherboard itself. This applies to _all_ ATX boards, not just the
    The only way to fully switch off the board, is to turn it off at the wall.
    Otherwise the standby supply will still be running. However given the tiny
    wattage involved on this part of the supply, I would have expected the fan
    to stop. I'd suspect that the temperature detector is set a little too
    sensitive for this part of the circuit, or that your enviroment is a bit
    warmer than the manufacturers expected. On some supplies with this type of
    feature, there is an adjustment for this.

    Best Wishes
    Roger Hamlett, Jan 25, 2005
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