Asus P4C800-E POST Failure Weirdness

Discussion in 'Asus' started by Steve Sr., Jun 29, 2011.

  1. Steve Sr.

    Steve Sr. Guest

    Paul & Other Asus Gurus,

    I have a system built around a P4C800-E motherboard. It is not
    overclocked and has been reliable for a number of years. Recently it
    developed a video noise problem which appear to be the video card
    which I replaced with an EVGA 512MB 8X AGP unit.

    during the video card replacement I noticed some bad caps on the
    motherboard so replaced all of the main electrolytics with Nichicon HZ
    series replacements. On re-powering the system I noticed an
    intermittent burning smell emminating from the power supply, an Antec
    True Power 430. I opened the supply but didn't see anything obviously
    burnt. I did see some more bad caps in the output section of the
    supply but since the PC was working I put it all back together and
    began researching a new power supply.

    4-5 weeks elapsed before receiving the new supply. During this time
    the system continued to work flawlessly. The chosen replacement supply
    is a Seasonic by Corsair TX-650 V2. Immediately upon installing this
    supply I began to experience all kinds of weird POST failures.
    However, before blaming the power supply I actually put an
    oscilloscope on it to look at the ramp up of voltages and the PWR_OK
    signal. All of this checked out to the ATX specification and the
    in-circuit voltages were almost perfect when measured with a good
    digital meter.

    The initial symptoms were black screen, no beeps. The same may happen
    on a subsequent power up or eventually it will POST but give a bogus
    "Overclocking Failed!" message. From this point either restoring BIOS
    defaults or just entering and exiting the setup without changing
    anything will result in booting to Windows. Once it gets to Windows it
    is rock-solid reliable until the next cold boot (usually the next
    day). Another interesting thing is that once everything is "warmed up"
    it will POST and boot properly until it is allowed to cool off usually
    overnight. As far as component temperatures go the CPU and GPU are
    both at about 50C. Hard drives are about 27-29C. This is with the
    tower case sitting non-optimally horizontal on my desk.

    This system has 2-1GB sticks of Corsair ValuSelect RAM (Upgrade 2008)
    and 2-512MB sticks of Crucial/Micron RAM (Original 2004). Thinking
    that this might somehow be memory related I began swapping memory
    sticks around. Things got really strange with ONLY the Micron RAM
    installed, first both sticks and then each individually. The main
    error now was "BIOS flash checksum bad" and prompts to insert a
    diskette or CD with the BIOS code on it! NOTE: This is not the same
    error as "BIOS Checksum Bad" which usually applies to the setup data
    being corrupted. Installing the corsair RAM first one stick and then 2
    allowed proper POSTing and booting. Thinking that this Crucial RAM was
    somehow bad I got an RMA and sent it back to Crucial. BTW, once POSTed
    this system ran MemTest86 overnight with no failures with BOTH memory
    sets in it.

    The joy didn't last long! The next day I was back to intermittent POST
    issues. However, it seemed that it didn't take as much "warm up" time
    as before for the system would boot normally.

    Using SpeedFan or CPUZ I noticed that the CPU core voltage was all of
    the way at the bottom at 1.56 volts. I read a post that suggested it
    be raised a little so I bumped it up to 1.66 volts. At first this
    seemed to have a beneficial effect at least getting through the POST
    more often. However now there are some new symptoms. Now if the board
    makes it through the POST it may fail to identify one or BOTH hard
    drives and prompt for bootable media. At this point the reset switch
    will cause a re-POST but the drives may or may not be picked up on the
    re-POST. Turning the power supply completely off (rear panel switch)
    thereby removing standby power for 30 seconds or so will likely allow
    both drives to be picked up on the next POST.

    So do any of you have any more thoughts on how to proceed to
    troubleshoot and fix this? Clearly all of the hardware including the
    new power supply can't ALL be bad. Troubleshooting to this point
    appears to point to a memory sensitivity but I don't see the
    connection with the new power supply. I have seen a few web reports of
    similar symptoms with this same MB but no conclusive cause and/or fix.

    If I had to guess it would appear that the BIOS is too agressive at
    setting memory perhaps before even configuring it to the setup data.
    When this issue first appeared I tried turning off "Performance Mode"
    in the BIOS. As I recall the system then POSTed but Win 2K threw an
    "IRQ not less than or equal" Stop error on 2 consecutive boots so I
    turned it back off. Apparently this was some sort of memory driver
    error that Windows couldn't handle.

    Your thoughts?


    Steve Sr., Jun 29, 2011
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  2. Steve Sr.

    Ghostrider Guest

    Did I read somewhere that you had changed the CMOS battery? If not,
    this might be the culprit. The P4C800-E is a little dated and the
    original CMOS battery, if not recently replaced, is suspect.

    Ghostrider, Jun 29, 2011
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  3. Steve Sr.

    Steve Sr. Guest

    GR, Thanks for the suggestion. I did think of this after reading other
    posts. I measured the battery voltage after the system had been
    unplugged for approximately 16 hours. It read 3.07 volts under the
    load of the motherboard which I would call good.

    Tonight at first it wouldn't POST. Hitting the reset switch allowed it
    to POST but It didn't detect the boot drive. Out of desperation I
    reset the CMOS data with the jumper according to the procedure in the

    It POSTed the first time after this and properly detected both hard
    drives and booted properly after I configured the BIOS settings. We'll
    see if this holds but I am not confident. I don't know how this would
    be any different from "loading BIOS defaults" which I did several
    times in response to the original "Overclocking Failed!" messages.

    Steve Sr., Jun 30, 2011
  4. I know it doesn't make sense since you said the CMOS batt was at 3.07v,
    but try replacing it anyway if the problem returns.

    It's not common (IIRC, I've seen about 4 cases like this in the last 10
    years), but I've had "good reading" CMOS batts screw up like this.

    At worst case, you are only out the cost (<$5) of a new batt.

    FYI (for evereyone):
    The big chain auto parts places are now stocking CR2032s (and others).
    Since they are also used in many car fobs, it makes sense.
    The local O'Reilly's has 2 - 2032s for $4.98.
    It's nice to know when you need one (as in visiting someone and getting
    stuck with the "can you fix my pooter" gig).

    "Shit this is it, all the pieces do fit.
    We're like that crazy old man jumping
    out of the alleyway with a baseball bat,
    saying, "Remember me motherfucker?"
    Jim “Dandy” Mangrum
    Nobody > (Revisited), Jun 30, 2011
  5. Steve Sr.

    GMAN Guest

    Walmart usually has them for $2.99
    GMAN, Jun 30, 2011
  6. I know. The local mom 'n pop pooter stores often have them for a buck
    each here, out of bulk trays. That's my usual source.

    If you need one and the autoparts place is 1 mile away and WallyWorld is
    14 (like here), and it's 9PM and you don't have a spare on hand... which
    would you choose?

    "Shit this is it, all the pieces do fit.
    We're like that crazy old man jumping
    out of the alleyway with a baseball bat,
    saying, "Remember me motherfucker?"
    Jim “Dandy” Mangrum
    Nobody > (Revisited), Jun 30, 2011
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