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    Gigabyte K8VM800M - What's causing this video problem?

    After some time, the display gives a vertical band pattern, especially while 'stressing' the computer by running a checksum program to check a 2.8G video file.
    Checks that i've done:
    1. Removed video card (now using on-board video)
    2. Swapped monitor
    3. Swapped/removed RAM sticks
    The input caps are 3 X 16V KZG
    The output caps are 3 X 6.3V MBZ.
    All the caps look good, but i'm aware that they may fail with no visible signs.
    Could faulty input/output caps cause this issue?

    The square in the picture is the mouse pointer, that responds well when moving the mouse.
    The computer can eventually be shut down by pressing the "windows key" then U U.

    Or is this pointing more to a problem with the K8M800 NB chip which is responsible for creating the video output?
    Attached Files
    Last edited by socketa; 05-13-2016, 05:08 PM.

    #2
    Re: Gigabyte K8VM800M - What's causing this video problem?

    There is a ram limitation on that board. If using 2 sticks of DDR 400 Mhz with both sides of each stick populated with chips the buss will drop down to 333 Mhz speed.

    Comment


      #3
      Re: Gigabyte K8VM800M - What's causing this video problem?

      Yep,
      Thanks
      Was aware of that
      Any thoughts on what's causing the issue?

      Comment


        #4
        Re: Gigabyte K8VM800M - What's causing this video problem?

        if the problem doesnt occur on a cold boot and the display looks flawless when cold, it could point to overheating since u said the problem is exacerbated by stress-testing (high temps).

        try to reapply the thermal paste on the northbridge. gmch northbridges tend to run rather hot. try to ghetto mount a small 40-60mm fan on the nb heatsink as well.

        imo gmch northbridges should be actively cooled. too many manufacturers make the mistake and skimp on active cooling for gmch nb chips. i've seen datasheets for many gmch nb chips and their tdp is typically 20++w which requires active cooling. i've had a 19w tdp passively cooled discrete gpu overheat to 80+°C even in an open-air test bench!
        Originally posted by socketa View Post
        Could faulty input/output caps cause this issue?
        its possible. due to the age of the caps, they could have dried out quietly without visible signs. if a cap dries out, it goes very high esr and that stresses out the mosfets making them work harder and produce more heat. the heat then gets conducted to the nb chip making it heat up even more.

        if u dont have an esr meter, just get rid of the kzg first and see what happens. leaving more than ten year old kzg bad caps on a board is never a good idea if u ever want a long-lasting and trouble-free board...

        Comment


          #5
          Re: Gigabyte K8VM800M - What's causing this video problem?

          Thanks,
          looks like i'll be testing/replacing the KZG's.

          i've got an esr meter
          The problem has now shown itself on a cold boot.
          The NB doesn't get hot - only 27 °C
          Running the checksum app on the 2.8GB file causes the problem (but that's only using a small % of CPU) - but if i play 3 videos, all at once and cpu goes to 100%, there is no problem.
          So i installed the XP operating system on another computer (same model board) as a comparison - no problem.
          Removed the drive and plugged it into the problematic board, and the problem reappeared (on both IDE slots).
          On IDE1 slot, XP was taking about 10min to load, now it doesn't want to load at all.
          The drive gives a few seconds of chirping and also get this message: "Boot disk failure. Insert system disk and press enter"
          There's no problem booting from IDE2
          Last edited by socketa; 05-16-2016, 08:40 PM.

          Comment


            #6
            Re: Gigabyte K8VM800M - What's causing this video problem?

            Took out the KZG input and MBZ output caps - they all test good.
            Replaced two of the input and the three output caps with HM's.
            Stuck the board back in the box, and no surprise - this didn't fix the issue.
            Probably should have checked the mosfet temps (as per post #4) before resorting to removing the caps.
            Any more clues?
            Last edited by socketa; 05-17-2016, 02:17 AM.

            Comment


              #7
              Re: Gigabyte K8VM800M - What's causing this video problem?

              Have you updated the motherboard BIOS to the latest version?
              Also check the caps around the rest of the board, if any 1000uf or larger Nichicon HM with a 2004 or earlier date codes are present remove them and use new replacements.

              Comment


                #8
                Re: Gigabyte K8VM800M - What's causing this video problem?

                where did u get that temp reading of 27°C for the NB? was it from the mobo sensor readings or by touching the heatsink or measuring with a thermometer or temp probe? im asking cuz afaik the via k8m800 chipset does not have a built-in temperature sensor. so the temperature reading u are getting from the mobo sensors is likely that of the board temperature.

                Comment


                  #9
                  Re: Gigabyte K8VM800M - What's causing this video problem?

                  Originally posted by Sparkey55 View Post
                  Have you updated the motherboard BIOS to the latest version?
                  No, the BIOS has not being updated
                  The current version is FB
                  i 'successfully' updated it 4 times using boot disk flash utility and @BIOS utility - so that's twice with version FC and twice with version FD.
                  But when i check the BIOS version through the command "wmic bios get smbiosbiosversion", and with Speccy, and with system info, they all say that the version is FB.
                  Some change to the BIOS was made, because when the machine reboots, i have to change the hard drive BIOS setting back to LBA each time (or else i get the "Disk read error. Press ctrl+alt+del" message at boot)

                  Originally posted by Sparkey55 View Post
                  Also check the caps around the rest of the board, if any 1000uf or larger Nichicon HM with a 2004 or earlier date codes are present remove them and use new replacements.
                  Yes, i'm aware of that one, all the smaller 1000uf caps are MBZ, and they all look good.

                  Originally posted by ChaosLegionnaire View Post
                  where did u get that temp reading of 27°C for the NB?
                  Multimeter thermocouple touching the heatsink.
                  Last edited by socketa; 05-17-2016, 06:53 PM.

                  Comment


                    #10
                    Re: Gigabyte K8VM800M - What's causing this video problem?

                    What board rev. do you have 1.x or 2.x ?

                    Comment


                      #11
                      Re: Gigabyte K8VM800M - What's causing this video problem?

                      check the bios rev. that actually shows on the screen just before it boots into the OS. Do not rely on third party software for this info. You may need to disable the quick boot feature in order to see the first line of info.
                      Last edited by Sparkey55; 05-17-2016, 09:38 PM.

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                        #12
                        Re: Gigabyte K8VM800M - What's causing this video problem?

                        Since the time is late here, i use drdflash.exe to create a boot disk for flashing. Copy just the bios flasher and the bios file onto the floppy, then boot to the floppy and type the flasher name then press space bar then type the bios file name and press enter. Be sure to clear the bios after the flash if sucessful. Also make sure that you unlock the bios protection in the settings to be able to flash it.

                        Comment


                          #13
                          Re: Gigabyte K8VM800M - What's causing this video problem?

                          Have Rev 2.0
                          Used Qflash to flash the BIOS
                          The boot screen gives K8VM800M-R2 FD (FD is the latest BIOS version), which is exactly what the other (good) board displays.
                          (so, yeah, looks like that info isn't updated on XP system information, which still shows FB)
                          So the the BIOS has being updated successfully.
                          But still the video issue remains
                          Last edited by socketa; 05-17-2016, 11:25 PM.

                          Comment


                            #14
                            Re: Gigabyte K8VM800M - What's causing this video problem?

                            doesnt look like a bad bios chip or bios flashing gone wrong as the board would bitch about the bios checksum mismatching and even refuse to show anything or post if the bios code or chip was bad.

                            it may have to come to push comes to shove... try reflowing the NB if u have the tools. since a lot of other stuff was ruled out. i also have a via s939 board and was told by another member that via boards are considered "low-end" so the manufacturer may have cheapened out on the bga soldering so it may need a reflow after awhile.

                            also, was the board ever exposed to lightning or some kind of high voltage surge? did the board become like that after a storm or power spike in your area? if so, u might have a high-voltage esd partly dmged NB. that would be unfixable, im afraid.

                            i wonder if momaka can chip in to help with this as he has the asus s939 version of this board.
                            Last edited by ChaosLegionnaire; 05-18-2016, 12:09 AM.

                            Comment


                              #15
                              Re: Gigabyte K8VM800M - What's causing this video problem?

                              Try swapping the CPU between the two boards; about the only device left to swap.
                              Will the problem happen during a vga bench run like futureMark 3DMARK?
                              Are you using the same PSU between the two boards?
                              What make and model PSU and have you checked it for bad caps?
                              Have you changed out the thermal paste under the northbridge?
                              I have read that at least one of the memory slots could be faulty by virtue of loose contacts, not all boards show it though.

                              Comment


                                #16
                                Re: Gigabyte K8VM800M - What's causing this video problem?

                                Reset the CMOS battery - still have video problem.
                                Board has always being protected with surge/spike protection at wall outlet.
                                PSU is only a 2 or 3 years old, and voltages are in spec.
                                Haven't changed the NB thermal paste - NB heatsink is stuck on well, and only gets warm.
                                Already have tried all combinations of memory sticks/slots
                                Last resort will be an attempt at a stove element/heatgun reflow - but buying the good flux will be worth more than 2 or three of these boards - if it comes to that, it will get shelved.
                                These boards are not ROHS, so i thought that if it was previously working fine, and the was chip not getting hot, then it would be unlikely that the BGA soldering would crack.
                                Will move onto trying a different CPU tomorrow.
                                Last edited by socketa; 05-18-2016, 12:34 AM.

                                Comment


                                  #17
                                  Re: Gigabyte K8VM800M - What's causing this video problem?

                                  Changing the CPU and PSU made no difference
                                  Last edited by socketa; 05-18-2016, 04:38 PM.

                                  Comment


                                    #18
                                    Re: Gigabyte K8VM800M - What's causing this video problem?

                                    Is the board in question warped or cupped in any one or more directions? If so try mounting the board on a flat surface to take out any warpage.

                                    Comment


                                      #19
                                      Re: Gigabyte K8VM800M - What's causing this video problem?

                                      .
                                      Last edited by socketa; 05-19-2016, 01:55 AM.

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                                        #20
                                        Re: Gigabyte K8VM800M - What's causing this video problem?

                                        The board is pretty much flat, only about 1-2 mm depth bending.
                                        While removed from the case, i reconnected the cables, and put it on a hard cardboard box with the edge of the box aligned with the (ports side) edge of the NB.
                                        Powered it up and then pressed down firmly on either side of the board using the edge of the box as a fulcrum, and the checksum application ran on the same files without the video failing.
                                        So this is the first time running that checksum app (takes about 7-8 minutes) on those video files, without the video problem, out of about 20 attempts.
                                        Of course the video has now failed since taking the pressure off, but the pattern on the screen is quite different than usual.
                                        Will try this a few more times to see if the result is repeatable.
                                        Last edited by socketa; 05-19-2016, 02:06 AM.

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