TechSpot

ASUS motherboard problems

By Hodsocks
Mar 7, 2003
  1. I have just replaced a motherboard and processor and am having a strange problem. The system is now as follows:

    ASUS A7S266-VM
    Duron 1200MHz
    192Mb SDRAM

    I have installed the above items but am having slight problems with it. The operating system is Win 98. When I switch off the computer throught "Start" and "turn off computer" the machine powers down OK except the keyboard still has power, the cd-writer light stays on but dimly and the HD light is on but dimly. Although the cd-writer light shows power the cd will not do anything else. The LED on the mother board also stays lit.
    When I come to power up there is no response from the machine. If I disconnect the power to the computer and reconnect and then hit the power switch it powers up.
    The light on the cd -writer goes off and the other lights act normally.
    I have checked all the connections and the bios settings and all are set as default.
    I have tried changing the psu but with no improvement.
    Have you any suggestions as to the cause of the problem, I am at a loss.
    Thanx in advance
     
  2. Nic

    Nic TechSpot Paladin Posts: 1,928

    Please provide more info ...

    What did you have before, when your system was working?
    Is your case and psu atx compliant?
    Does your system work properly when you have successfully booted to windows 98?
    Provide as much info as possible, as right now there are just too many variables to draw any reasonable conclusions.:confused:

    One last thing, if you have made such a significant change to your hardware, then I would hope that you also reinstalled win98 and all your software. Its not a good idea to just use your existing installation.:cool:
     
  3. StormBringer

    StormBringer TS Rookie Posts: 2,871

    There is an LED on most mobos that always stays lit. Other than that we'll need more info to determine anything else. Specificly, I would ask how your PSU is connected to the mobo and the power button. It sounds like there may be a problem there. It sounds like a latching voltage problem.
     
  4. Hodsocks

    Hodsocks TS Guru Topic Starter Posts: 536

    Originally it was a MSI 6147 Board with Pentium 2 400MHZ, 64Mb RAM. Yes it is an ATX PSU and case.
    I changed the m/b, processor and ram and added a cd-writer. It was working fine before I changed things.
    Once its powered up everything works fine. If I put it into suspend mode it will happily come out of it.
    The psu is connected via the usual ATX connector, I have checked the power switch connections on the board and they seem to be ok. The connections on the board are marked up differently to the manual, but I have tried connecting up both ways and I only have power when connected as per.the manual. There is no reset button on the case.
    I keep wondering whether it could simply be a static problem.
     
  5. Nic

    Nic TechSpot Paladin Posts: 1,928

    If sounds like your machine is not powering down properly.

    You could try some of the following ...

    1. Disable all power saving features in your bios if running win98. Make sure that the bios setting for the 'Power Switch' is set to 'ON/OFF' (or something like that) and not 'Standby' or any setting that does'nt sound like OFF.

    2. Make sure you have installed all drivers supplied on the CDROM that came with your mainboard.

    3. Set the safe default settings in your bios to see if things improve.

    4. Try resetting your Mainboard (see M/B manual) - usually just a jumper setting, if you suspect a 'static' problem.

    5. Take a look in device manager (control panel, system) and look for any conflicts - yellow exclaimation marks on your devices '!'). If you find any then uninstall the device (right click and select uninstall).

    6. Reinstall Windows 98 - a mainboard change looks like a completely different PC to your OS. While it will sometimes configure your new hardware properly, most often there will be unpredictable and random behaviour - so I would always reinstall when changing the mainboard.

    Hope this helps.:cool:
     
  6. Hodsocks

    Hodsocks TS Guru Topic Starter Posts: 536

    Excuse my ignorance Storm, but what's latching voltage.
     
  7. Rick

    Rick TechSpot Staff Posts: 6,305   +52 Staff Member

    The first question I have for you is the computer really OFF. By off, I mean do the fans stop spinning such as the CPU fan?

    If so, there might be something wrong with your motherboard. This is very abnormal behavior. Under no circumstance can I think of why your HDD LED would be dimly lit while your computer is OFF, including your CDROM etc...

    If your computer really isn't turning itself off, then software may be the cause. It could have something to do with ACPI, in which case I would recommend using APM in your BIOS options.

    If your computer is actually turning itself off, but drive lights are on etc.. Then this is definitely a hardware problem.
     
  8. Nic

    Nic TechSpot Paladin Posts: 1,928

    I know what Storm means ...

    By 'latching voltage' (electronics terminology) he is saying that there is still power being supplied to your mainboard because your power supply is not being switched off fully. On ATX PSU's the power ON/OFF is controlled by your mainboard, which in turn is controlled by your OS. This means that either your mainboard, or your OS, is not correctly controlling the PSU (please excuse the acronyms - I'm sure you know what they stand for as they are common ones).;)

    [ I was bored so I answered your question - please excuse ]:cool:
     
  9. acidosmosis

    acidosmosis TechSpot Chancellor Posts: 1,574

    Hmm.. maybe try one of the following:

    1.) You might want to take to make sure you plugged everything in correctly.. such as the led lights, etc.
    2.) Try turning the power supply powers switch off after you power down (if you have one).

    Other than that, I'm clueless, lol..
     
  10. StormBringer

    StormBringer TS Rookie Posts: 2,871

    That is exactly what I meant Nic.
     
  11. Hodsocks

    Hodsocks TS Guru Topic Starter Posts: 536

    Rick, to answer your question, the power is off...processor and PSU fans have stopped spinning, hard drive stopped spinning, The lights are the only suggestions of power.
    I am coming to the conclusion thats its either a windows problem or a duff motherboard, maybe I will reload windows and see if it makes a diference.
     
     
  12. StormBringer

    StormBringer TS Rookie Posts: 2,871

    This suggests that Windows is not the problem. I am still leaning toward the latching voltage. It could be something on the mobo, or it could be the power button on the case itself. If you have another button, try swapping it out. You also might want to try turning off APM or whatever your system uses for autoshutdown, then shut down and power the system off using the power button on the case. See if that makes a difference

    That LED on the mobo is probably not going to go out unless you power off with the PSU switch itself. As I stated before, most mobos have an LED that stays on as long as power is connected to them, and power is always connected to ATX mobos as long as the PSU is connected, plugged in, and the PSU switch is on.
     
  13. Hodsocks

    Hodsocks TS Guru Topic Starter Posts: 536

    I did try disabling the APM in the bios but it made no difference, I have also tried switching the machine off with the power button rather than thro windows and still no improvement.
    I am tempted to say the power button is ok but only cos it was working ok before I switched boards.
    Like you I am tempted to suspect a problem with the mobo as I have never had a problem with any of the other boards I have changed. It all suggests that the mobo is not shutting the power off completely and is feeding a trickle to certain areas of the board.
     
  14. Nic

    Nic TechSpot Paladin Posts: 1,928

    Once your machine is powered down from windows, and the drive lights are still on (as per fault), what happens when you hold the power switch in for a few seconds? Does your machine then power down fully?
     
  15. StormBringer

    StormBringer TS Rookie Posts: 2,871

    This is what I'm thinking. This could be a problem with the board, the switch, or the connector. It could be as simple as an incorrect or loose connection, or it could be a faulty component.
    Double check all your connections to the board from the PSU and the switch. Make sure they are getting good contact, no oxidation, and make sure nothing is backwards or otherwise incorrect. If you have already checked it, do it again to be sure. I it is better to be reduntant than to replace something that isn't faulty.
     
  16. Nic

    Nic TechSpot Paladin Posts: 1,928

    It can't be the switch, as then it would'nt power up either.;)
    Sounds more like the OS to me, but I could be wrong - nothing to lose now.:cool:

    If all else fails then I guess you need a new mainboard.:blush:
     
  17. Hodsocks

    Hodsocks TS Guru Topic Starter Posts: 536

    Nic, I tried holding it in for a while.....4 secs + and it made no difference, still power to the light.

    I have had the connections to the board on and off so many times to check them and to turn them around you wouldn't believe it.
     
  18. Nic

    Nic TechSpot Paladin Posts: 1,928

    OK, then I guess your mainboard could actually be faulty.
    Thats really bad luck, as ASUS are normally top notch.

    Here's a link about ATX PSU's that you may find useful ...

    ATX PSU - How it works

    If it was me I'd try reinstalling the OS, and if that does'nt work, then I'd get the mainboard replaced. Sorry I can't help more than that, but it looks like you may just have been unlucky with your mainboard.:blush:

    One last test to try ...
    Boot to a floppy from power off.
    Then try holding in the Power button to check if your machine switches off correctly. If it does then the problem *may* be caused by your OS (but may not be, as your OS does not use the power switch to power down, but it would show that the power down circuit works, although the circuit that handles the soft power down option does'nt). If it does'nt then your motherboard looks like the culprit, as all other suggestions have already been explored.
     
  19. StormBringer

    StormBringer TS Rookie Posts: 2,871

    Actually, it could still power up. The way it works is the reason why it would still be able to power up. The problem could simply be that it is sticking, or it may not be connected properly.

    I am pretty sure that by disabling Power management, you can pretty much remove the OS from the equation. The OS no longer has control over the Power down. This would mean that you would get a shutdown screen instead of having the system shut itself off completely. Since there is still a problem after doing this, it suggests the problem lies elsewhere.

    One other thing I might suggest is disabling ACPI in the BIOS if you haven't already tried that. This along with APM are the two different ways to control auto-shutdown through the OS(though ACPI has other functions as well)
     
  20. Nic

    Nic TechSpot Paladin Posts: 1,928

    ----------------------------------------------------------------------
    StormBringer ...
    I am pretty sure that by disabling Power management,
    you can pretty much remove the OS from the equation.
    ----------------------------------------------------------------------


    I can understand why you might say this, but please remember that when you tell the OS to shut down, the OS cannot physically *press* the power switch, it simply sends a signal to the mainboard (via the bios), which will then signal the PSU to switch off.

    The Power switch is a momentary contact switch that does'nt latch but simply sends a signal to the mainboard, which then instructs the PSU to switch itself off/on.

    When shutting down windows the power off signal originates from the OS and not the power switch.

    If the shut down signal from the OS did not reach the mainboard then the PSU would not know to switch itself off.:cool:

    Anyways, I think that we are done now as its looking more and more like a faulty mainboard. :eek:

    Final Comment ...
    Now that I think of it, the mainboard *must* be faulty. The PSU *is* powering down otherwise the case fans (12v) would be running and the hard disks (12v motors) would still be spinning etc. Sounds like the 12 volt line is powering down, but not the 3.3/5 volt lines. Never come across this type of problem before, really I should have clicked earlier - Sorry!:blush:
    Ah, the fealing of enlightenment hits me!:confused:
    It was a good discussion though, and much fun was had by all. :D
     
  21. Justin

    Justin TS Rookie Posts: 1,595

    Don't forget that on any ATX PSU, there is no full "power off" excluding flipping its rocker switch (assuming it has one) in the back. On many motherboards, especially on server motherboards or custom case chassis, you will have diagnostic LEDs that will be lit as long as the PSU is plugged in. 3.3V and 5V do not always completely shut down for a reason - they stop supplying power across device only, but still supply to the motherboard, which the LEDs draw power from.

    You can confirm this is true by taking a variable color switching LED (green/red), and plugging it into the power LED header... if it lights up when the computer is off, and reversing it causes it to turn RED.

    However, having ALL leds lit up is definately not a good sign at all, definetely a defective PSU or mobo.
     
  22. Nic

    Nic TechSpot Paladin Posts: 1,928

    Yes, we know that 5v ('PS_ON') will remain on the mainboard after shutdown. In this case, as you quite rightly say, there should not be the additional power to the device LEDs. The PSU has already been eliminated as the culprit as it has been swapped out, but the fault remains, therefore the mainboard is the suspect here.
    :grinthumb
     
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