Bizaare fan failure problems... any ideas?

[Alluvian]

My system:
Motherboard: A7N8X (2.0) I forget my bios rev...
Processor:  AMD Barton 2500+
OS: Windows XP
Power Supply:  450 watt generic
Video Card: Gainward 5900XT golden sample
Drives:  1 dvd drive, 1 cd burner, 1 EIDE 80 gig western digital HD, obligatory piece of crap floppy
Suspicious MB 'features': Q-fan.  Supposed to run fans slower when cpu is cool and then ramp them up when it gets hot.  It was disabled by default and I have left it that way.

The setup
Setup my system this weekend for the first time.  Ran fine sunday and monday using it heavily in 3d games.

Tuesday the system turned off a few minutes into a 3d game.  Restarting met with immediate shutdown again. (within a second)

Opening the case I found the fin fan cooler on the cpu to be extremely hot (too hot to touch for more than a second or so).  I figured the cpu overheat protection kicked in, so I let the system cool down till the metal was just a little above room temp.

The problem
Starting the system again I noticed that the cpu fan was not moving.  The case fan was working (plugged into the chassis fan connector on the mb).  I shut down immediately after getting into windows.

I wanted to see if the fan or the mb connection was faulty, so I tried plugging the cpu fan into the chassis fan connector and the chassis fan into the power fan connector.  This time when I started up, both fans started spinning... for about 2 seconds.  Then they coasted to a stop.

I have not gotten the cpu fan to spin since then.  The chassis fan came with two different connectors.  A motherboard 3 pin connector, and a daisy-chainable power supply connector.  I tried the chassis fan hooked up to the power supply and it ran fine.

I am considering getting a power supply daisy chain to cpu fan adapter to run that as well.  I will lose all fan control and fan monitoring though, so it is not a solution I really like that much.  In the case of a fan failure I guess the C.O.P. system will save me again.  I am sure glad it was there last night.  As annoying as it is to have a system shut down, having it fry itself would be so much worse.

Do you have any idea why I would experience full fan failure like I have?  The chassis fan is obviously fully functional as it works fine with the power supply now.  I don't believe my moving the cpu fan connector around should have hurt anything.  The fan was already not working.

Is this a bad motherboard connection?  I don't know if the fans split off a single lead at any point where one bad connection could lead to all three failing.  That does not even make  sense because at one point the case fan was working but the cpu fan was not.  I thought for a moment maybe the power supply possibly had a lead that set fan voltage that could have been bad, but again at one point one fan was working and the other not...  I still have not verified if the cpu fan is functional at all anymore.  no real way to test it on it's own unless I find a power supply adapter for it.

I am strongly leaning toward the motherboard being messed up.  I don't have all the pertinent information to fill out the web tech support form at asus (they want serial number and shit).  Tonight after work I will be running by some computer shops and seeing if a connector exists to hook the cpu fan up to the power supply directly.

[SirBruce]

The CPU fan may be bad.  Replace it and see how if that works.

If not, I'm pretty sure the motherboard is busted.

Bruce

[Alluvian]

Well, something weird is happening beyond just the cpu fan.  Because the chassis fan won't work plugged into the MB anymore either.  When it used to work just fine.  Unless I fried something by moving the cpu fan connector off to the chassis fan connector.  I can't imagine frying the motherboard connection by moving the cpu fan.  Not like you can plug the thing in backwards.

[Venkman]

Does the MB connector put out the same amount of power as the chassis fan connector? It may not, which could be contributing to the results your finding. Buying another CPU fan is at least going to remove a variable quicker :)

[Alkiera]

I've heard of occasional problems with overloading the fan circuit on a motherboard, by having very large fans, or using 'Y' connectors to connect multiple fans to a single connector.  If the fans draw too much power, the MoBo may not be able to handle it.  It's theoretically possible the circuit is burned out.  It's especially possible if the CPU fan in question is faulty inside, has a short, or some similar issue that is causing it to draw more power than it should.

Really, it shouldn't be a problem if you can hook the fans up to the powersupply and get them to work.  Yes, you lose the fanspeed monitors, but monitoring the actual temperature is at least as effective at determining the state of your PC's cooling system.

--
Alkiera

[Alluvian]

I have the standard socket A cooling system of a fin fan cooler with an attached fan.  Can the fan even be removed from the cooler without having to break the thermal seal with the CPU?  I hate fucking with the thermal seal if I don't have to and it is working fine (the fast heating of the fin fan cooler certainly indicates a good thermal contact).

I will have to look at it more to see if the fan itself is removable.

[Rof]

Generally you can take off the fan without disturbing the heatsink. The screws in the corners of the fan housing secure it.

Of course some designs may not be built that way, but most of them I've seen (AMD stock heatsinks, for example) just used a few self-tapping screws shoved in between the heatsink fins.

One thing some modern mobos have is "shut down on CPU fan fail", which might be related to your problems.

[Trippy]

This might be a power supply problem. If you have another power supply you might want to try that. Or if you have an older video card you can swap that in temporarily. It kind of sounds like your power supply isn't putting out enough current (probably on the 12V line). Reducing the load (putting in a video card that doesn't require the extra power) or increasing the current (another power supply) are ways to test this. If you are overvolting anything (for overclocking purposes) reset those back to defaults as well.

[Murgos]

Flick your CPU fan, does it spin freely?  Or does it come quickly to a halt?

If it spins freely the fan is probably still good look elsewhere for the problem (Off hand guess?  Motherboard or power supply if you have a multimeter check the voltages on the fan power connecter on the mb if those are within spec check the voltages coming from the power supply itself).

If it comes quickly to a halt either the bearings or the bushings or both have probably burnt out this could be because its a bad part (no, or too little, grease on the bearings and you would get the symptoms you described - works for a while then dies) or it could be because either the MB or powersupply are bad.  Get out multimeter and check.

P.S.  Many modern motherboards will tell you what the voltages are in the  CMOS, no need for the multimeter UNLESS you need to check the CMOS for sanity.

[Delf]

Modern AMD motherboards won't start up if they don't sense a running fan at startup. So when you tried plugging the CPU fan into an alternate power source, that meant there was no signal on the pin in the CPU fan header that senses the spin. That's why it shut down after a couple seconds. (The alternative is to burn up the CPU in literally seconds if it's not properly protected by a working heatsink.)

Beyond the previously mentioned possibilites, many of which are plausible, it could be that your CPU fan isn't producing a speed signal (on the yellow wire -- you do have a yellow wire on the CPU fan connector, right? Should have three wires going to the three pins on the mobo connector.)

Ideally you'd hook that CPU fan to a power supply and see if it works. But ATX power supplies need to be fooled into operating, and that's a little complicated to explain here. I'd think hard about taking the box to a competent tech to sort out.

Edit: rereading your experience, I'm inclined to think you've got a textbook case of infant mortality in the motherboard. The fact that it worked fine for a couple of power/temperature cycles and then quit is pretty suspicious that way. Simplify the system by removing/unhooking everything you can and then try rebooting, to try and ensure that it's not a failure in one of the other components that drags the rest of the system down. If you bought the parts locally, I'd take it to their tech for troubleshooting.

[Alluvian]

Okay, got a 3 to 4 pin fan power supply adapter so I was able to daisy chain the cpu fan.  It started up fine without the CPU monitor installed, and the fan was running well all last night during a marathon COH session (got my first Dr. Vahz kill, yeah me.)  The fin fan cooler was actually COOL while playing.  I kept a close eye on the wires leading to the cpu fan to make sure they were not getting hot in case the fan had a short in it and was drawing too much power.  All wires stayed cool though.

Everything worked fine.

So it looks like the fan power supply circuit on the motherboard is simply not working anymore.  I have done a lot of searching on google and the ASUS site and can't find a single person who has had a similar problem.

I just wonder if this is a sign of things to come or if I can accept this minor loss in functionality of the MB and move on with my life.  I think newegg will honor RMA for the first month, so I will probably mark my calendar for 20 days and see if any new problems have arisen.

My only other problem is that I can't play COH fullscreen.  When it switches to the login screen my desktop resolution switches to the game resolution and then the login comes up in what looks like a borderless window that is WAY too small for it.  And it does not resize to fit.  So I am seeing a little ~640x480 window off in the corner of the screen and the rest is not visible.  Changing the registry to reset resolutions has not worked, and I have been forced to play it in a window.

Very frustrating.  It worked ONCE the first time I tried.  Started up full screen but was in some low resolution.  So I reset the resolution ingame and it asked me to restart.  I did, and it looked great.  Then the next day it gave me these troubles.  That was the same day my CPU fan clunked out on me.  I don't think the two problems are related....  I so far have the cryptic tech support pretty baffled.  They are running me in circles with tiny responses each telling me to do one tiny step at a time... send dxdiag.... check my startup to see if it is clear of any resolution changing software... each response taking another day.

[Fargull]

If I am reading correct, your motherboard is still with in 30 days of purchase?  Take it back.  The motherboard is the central nervous system for your gaming pleasure.  If you think you can 'Get By' on something you know to have issues, then that is you.  I would not.

[Alluvian]

I get the shakes sitting at home without a computer though.  The others are already in their new roles as wife computer and art computer.

RMAing the MB is not something I really look forward to.  I am also not yet 100% on whether it is the mb or the power supply.  I would have to know if there is some mystery lead on the motherboard power supply plugin that is supposed to handle fan voltage.  If there is no fan voltage lead then I can probably safely assume it is motherboard.

Besides, I have horrible luck with tech support.  Like them telling me there is nothing wrong and charging me silly amounts of shipping.

[Delf]

I agree with Fargull, I'd return it. Try to get them to send you a replacement first so you're not without a computer. Some places will do that for you, especially if it's your only computer (hint: this is your only computer :)

There's no special power supply lead that provides fan power; this is pretty clearly the motherboard. It's not uncommon for electronics to fail early in their lifetime, and it looks like something in the fan control circuit has done that on you.

[Venkman]

I hear that man, but seriously, minor trouble now just becomes unworkable trouble later. I made the mistake of troubleshooting my rig when I got it rather than spending a few days offline while the vendor fixed what should have worked in the first place. 3 months later I finally had a computer that was fine. Of course, I'm not a tech either, and my previous computer played EQ just fine so I wasn't offline either :)

[Alluvian]

I loathe any move that requires me to break the cpu/cooler thermal seal.  Ever since I fucked up a 6 month project in a college lab course because 1 out of 10 thermal seals was bad when I painstakingly did everything right I have been borderline terrified of messing with the things.

Anyway, I still have a few weeks before I hit the 30 day mark.  Thanks for clearing it up that it IS the mb.  That is a big step in pushing me towards replacing it.

[Trippy]

I loathe any move that requires me to break the cpu/cooler thermal seal.  Ever since I fucked up a 6 month project in a college lab course because 1 out of 10 thermal seals was bad when I painstakingly did everything right I have been borderline terrified of messing with the things.

Anyway, I still have a few weeks before I hit the 30 day mark.  Thanks for clearing it up that it IS the mb.  That is a big step in pushing me towards replacing it.

The fans are powered by the same 12V line as the CPU, video card w/extra power connector, hard drives, DVD drives, etc.. It's much easier to swap in a different power supply to check to see if that's the problem than to swap in a new motherboard, even if you had a replacement MB handy. It's even easier still to swap in an older video card (video cards that don't need an extra power connector use just the 3.3V line).

[Alluvian]

Well, if the fans work fine daisy chained in with the cdburner and dvd then the power supply must be giving adequate juice, right?  And all other components seem to be functioning fine.

[Trippy]

Well, if the fans work fine daisy chained in with the cdburner and dvd then the power supply must be giving adequate juice, right?  And all other components seem to be functioning fine.

Yeah sorry I somehow skipped over that reply. That does sound like it's your motherboard unless you somehow have a cheap power supply that has dual 12V rails (I've only seen that in higher end power supplies).