Motherboard mystery

I have a computer problem that no one seems to be able to figure out.
The problem: During Startup Cmos does not properly load settings to start the Heat Sink Fan (best guess) ; it turns for half second and turns off. During this initial startup all fans come on the Hard Drive spins up and the Video Card Intiates. Everything appears to be normal with the exception of the Heat Sink Fan. The result is a blank screen.
Trouble shooting so far:
1 Unplugged the PSU from the wall waited for a few seconds and the selected the case power switch. No change
2 Unplugged the PSU from the wall and held down the Case Power Switch for 20 seconds plugged it back in and powered up. No Change
3 Unplugged the PSU switched the Jumper to join the CLR_CMOS for a few minutes switched the jumper back plugged the PSU back in and powered up. No Change
4 Reseated Video Card and Ram. No Change
5 Tried one stick of ram at a time. No Change
6 Reapeated #4 and #5 followed by #3. No Change
7 Removed comos battery. Powered up. No Change

The RAM Led lights Contantly on the Motherboard. On this particular motherboard the DRAM LED checks the DRAM in sequence during motherboard booting process. If an error is found , the LED next to the error decice will continue lighting until the problem is solved. Now I am not a Computer Scientist so I do not know what the exact "sequence" of the booting process but I do know that the CMOS holds the hardware setting that load into the bios. So I am wondering why the RAM Led would be blinking. In what way does the CMOS loading process affect the DRAM if any or does it check the RAM. Why is it blinking... in the USER Manual it says the the LED checks the DRAM. That makes no LED cannot check the DRAM.. I don't know what does but my guess is that the CMOS checks the RAM I could be wrong. Could the CMOS be corrupt. It appears to me that the LED starts blinking before the bios ever has a chance to load. The light starts blinking simutanueosly with power up.
The CMOS has been cleared several times during this troubleshooting process. Does anyone have any idea what this could be. The computer was running flawlessly and just shut down to a blank screen with no Heat Sink Fan. This has nothing to do with an after boot to windows or a BSOD I have had zero errors with this computer. It will not even load the bios or at least that I can see and I doubt it would work properly without the Heat Sink Fan running.
It is a new build and here are the specs:

CPU AMD Phenom II x6 1090T...Hard Drives are Crucial C300 and Samsung F3....Windows 7 Pro 64 bit...Motherboard: Asus M4a89gtd Pro/Usb3...Memory G Skill 1333Mhz Cas 7 1.5 (sx4gb)8GB Power Supply Corsair 750TX Graphics Asus EAH6850....Case Antec 900 The Computer was never Overclocked and was flawless.

Here is a link to a video the shows the 1 second cpu fan startup.

I have already recieved an RMA but this is a last ditch chance to fix it before I send it off

Any Help would be much appreciated
8 answers Last reply
More about motherboard mystery
  1. Welcome to Tom's Forum! :)

    Probable failures:
    * CM heatsink mount is not properly installed ; metal to MOBO short.
    * Standoff shorting
    * Front panel mis-wiring
    * Bad peripheral
    * BIOS less than 1301
    * Too much or No Thermal Paste

    Q - ANY Beep tones? {other then the 1 beep}

    Therefore, if it were me.

    Remove ALL connections including: GPU, ALL Headers {Ft Panel, USB, etc}, HDD & ODD {DVD}, peripheral including Keyboard & Mouse {I've seen a shorted mouse cause a post failure} and use the onboard GPU only.
    Setup: MOBO, 1 Stick of RAM, CPU + Heatsink, Monitor and PSU 24/4-pin.

    Use either a wire or screwdriver to short the PWR+ & PWR- to start.

    Failure, {Lazyman's Breadboard} unscrew all MOBO and PCIe screws, pull the MOBO away from anything conductive and dangle supported by a towel -- short the PWR+ & PWR- to start.

    Failure, look closely at the CPU Fan MOUNT; if there's any metal to MOBO then you've improperly installed. It should be:
    Screw ==> Plastic Mount | MOBO | Plastic Washer | {Standoff some models} | Top Mount | =< Nut
    Screw ==> Mount | Plastic Washer | MOBO | Plastic Washer | {Standoff some models} | Top Mount | =< Nut
  2. Thank you for your generous reply.

    It is possible that the Cooler Master Hyper 212 heat sink is not properly installed but I don't think so unless it is where the nuts make contact with the motherboard. Like Saint19's guide on this forum it appears that there aren't any washers. On my motherboard like Saint19's there seems to be circles drawn around the holes where the screws go through the motherboard and they have some sort of pattern in the circles. I am assuming that is the protected part of the motherboard and would not short. Here is a closeup of his installation mine is identical. Here is the Pic

    I found no reference on how to adjust the center screw the one in the middle of the pic just over the cpu. How tight does it need to be. I think I have it right but better safe than sorry,

    It seems like ghost because this computer worked perfectly for a month after the build. How could it suddenly have a short. And why is the Heatsink fan pin on the motherboard the only thing that is not working.

    I am going to try your next suggestion now... Remove ALL connections including: GPU, ALL Headers {Ft Panel, USB, etc}, HDD & ODD {DVD},................ I will update you on that tommorow.

    Thank you....
  3. I'm speaking of the underside of the MOBO; there are a lot of incorrect posts/videos on the 212+. And YES it's not that uncommon for the resin to wear-off 0~months later. I've seen plenty of 30+ days where this is the problem.

    In the case of 212+:
    Nut <= Mount | Plastic Washer | MOBO | Plastic Washer | {Standoff} | Top Mount | =< Screw

    Ghost - assuming my guess 'washer'; analogy it's like a water pipe, the dry-waller zips in a metal screw into the water pipe, months ro longer the screw corrodes and poof => instant water leak coming though the ceiling/wall. The vibrations wear off the resin poof => short.

    The 212+ uses a spring tension so you cannot over-compress the top mount on the CPU; just don't compress the spring all the way ;)
  4. I am afraid I failed at installing this if this is correct but the Cooler Master did not come with washers at least mine didn't. the back plate is made of the same material as the motherboard and sits right against the motherboard. The difference between how the AMD board and the Intel board attaches to the backplate is radically different... the back plate only touches the board on the corners with the intel.
    Here are 2 pics of the bracket on the back of my computer.

    Why would the Heat Sink Fan be the only Pin dis functioning on the motherboard. Could it be a corrupt CMOS chip
  5. There are a lot of tricks that you learn over time, this is one of them. I also use plastic washers to insulate on top of the standoffs, I apply silicone on top of the standoff to hold the washers in place. I've had shorts/grounding shorts before...

    The washers are not in the kit, and 99% of the time, ditto with the standoffs, it's not a problem. Then there's the 1% that can kill your MOBO, CPU, GPU and PSU so an extra nickel seems not to be a waste.

    Many of the Backplates/Mounts are plastic to avoid a problem. Assuming it is indeed the problem. The last time I had a very similar post solved -- it was a short. You can get into the maybe's all day. What I proposed rules-out a TON.

    If this fails then you need to do a full Breadboard and try the washers, failure use the Stock HSF.

    Failure, you're looking at major stuff: PSU, MOBO, CPU or RAM. The first step is to try a different PSU, then RAM.

    But when it comes down to it, component failure, 80% MOBO vs 20% CPU -- problem -- unless you have a replacement CPU sitting around there's nothing but guesses. Also, if there's an installation error you don't want it replicated.

    When I build, I always breadboard the system prior to installation. I want to see that everything is running. For complex water cooled builds -- a full bench + stress test & benchmark. If I want extreme OC and the CPU or GPU is from a mediocre batch why spend hours putting a water-block on and tearing it off -> putting a GPU back to OEM shrouding.

    Let's see what happens...
  6. BTW - Unless you've flashed the BIOS and 'suddenly' the MOBO fails to post -- I doubt it's a CMOS issue. However, a short can permanently damage you MOBO/CPU/GPU.

    Yeah, if you tighten the nut + CPU standoff too tightly yep you can also destroy a MOBO. Keep in mind a MOBO is sandwiched layers of pathways. Nothing needs to be really tight, this is not like a handlebar on a bicycle, its supporting a puny HSF - tight enough so it doesn't unscrew -- finger tight plus a 1/4+ turn.
  7. Ok so this is a great day for me. I read an obscure post specifically about my board. It said that you cannot put insulated washers between the screw and the motherboard because the board was designed to be grounded that way. There are small pieces of what appears to be solder within the circle where the screws make contact and and then ground to the back plating . This is the opposite of what most boards would need. I had sent my computer to my brothers office to be sent off and I was lucky enough to get it before he sent it. I immediately removed the washers and boom I had booted right up. Wow sorry to worry you guys so much and thanks for your help. This is a case of Antec who sent the washers expecting me to know what my motherboard wants. I am sure that some of the shorting issues on this board may be resolved with this fix. Thing is I still haven't seen any documentation about this in the Asus Manual or the Forum's. But I know it works. I have worked on this thing day and night glad this is over.
  8. So if you put everything back the way it was then you shouldn't have had the issue in the beginning.

    There's good grounding like on the TOPS of the MOBO screws {solder 'dots'} with the standoffs and there's shorts where the CPU Backplates Metal -> MOBO is NOT a good thing especially where a 'large area' is placed in direct contact to the MOBO.

    Nut <= Mount | Plastic Washer | MOBO | Plastic Washer | {Standoff} | Top Mount | =< Screw

    MOBO Standoff:
    Case | Standoff | Plastic Washer | MOBO | =< Screw ; Grounding via the 'Screw'

    If the HSF only makes limited contact on the backplate, screw point contact only, then a washer is not needed.

    Looking at you MOBO's picture the grounding 'solder dots/points' are on the top and clearly visable??!!!
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