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New System will not post 4

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treywalker

Programmer
Nov 28, 2002
12
US
I am having severe trouble with my new system. When I start it up it will go for 3-4 seconds (fan, hard drive, etc. all running) and then it shuts itself down. No beeps, no bios, no monitor output, no nothing.

I have searched everywhere and tried everything suggested, but to no avail. I have to assume that something is not working and that I need to replace it, but I don't know what. Any help is appreciated.

Here's what I've tried so far...
I went jumperless - no change
I took everything out except for the CPU, speaker (to hear beeps) and power supply. - no change
I took the MB off of the chasis (in case of a short) - no change
I plugged a fan into the the CPU fan slot (seems some mb's need to think there is a CPU fan) - no change
I've tried every combination of having things plugged in or not plugged in - no change except for what is mentioned below

One thing I can do to make it work differently is to take out the CPU. No matter what I have plugged in, if I take out the CPU it will start up as mentioned, but it will not shut itself off. Still no beeps, no bios, no monitor output, no nothing. But at least it doesn't shut itself off.

System Hardware:

Asus A7N8X MB
Corsair 512MB PC3200DDR
Athlon XP 2400+
Albatron geforce4 Ti4200 Video Card
Western Digital Harddrive
Samsung DVD/CD-RW
Swiftech Heatsink & fan

Please, somebody help me!!!!
 
Huh? "I plugged a fan into the the CPU fan slot (seems some mb's need to think there is a CPU fan) - no change"

You don't have a fan running on top of the heatsink and CPU?
 
Yes I do have a fan on top of the heatsink and it works. It's just that the fan uses a 4 pin 12v connector that plugs into the power supply. Not the standard 3 pin connector that connects to the motherboard.

Anyone with an idea? I don't want to send all of the parts back, but at the moment I can't tell what's wrong. My CPU bad? My Motherboard bad? Something stupid that I may be doing?

Thanks!
 
Going back to the CPU fan issue, did you use a fast 60mm fan with 3 pin wiring? (it needs to be ) slow 80mm fans (around 2,500rpm) sometimes don't detect either.
Sorry if I'm teaching your gran to such eggs but! you are fitting the heatsink the right way around? recess in base over socket "A" writing (can be fitted 180degrees out)
Clear cmos (jumper neat onboard battery)
If you still have know joy replace PSU.
Martin Please let members know if there advice has helped any.
 
I'm confused. We're centering on the CPU fan. Why? It is working as are all the other fans that are in my case. The 60mm CPU fan came with the heat sink and the heat sink was placed correctly. No offense taken :) However, it does not have 3 pin wiring, instead it has 4 pin that connects directly to the power supply. I don't see why this would be a problem...as I said, it is working.

As for resetting the CMOS, I did that several times (battery/jumper sequence), but to no avail.

And then you mentioned replacing the PSU??? What is your thought there? If everything has power, how could that be the problem. I'm not an expert, so I may just be confused, please explain.

Let me restate the issue so that everyone understands the problem I am having...

When I start the computer the fans/hard drive/cd-rw/lights/etc. come on. The monitor does not. About 3-4 seconds later the computer turns off. The A7N8X MB is supposed to have a self test that will beep (actually talk if you have a speaker pluged in other than the default case speaker) with a code. It should then go to the BIOS (if I hold delete). It's not doing any of this before it shuts off.

I ended up taking the CPU out and it stays running, but everything else is the same. No Beeps, no monitor and I can't get to the BIOS.

I'm not trying to be a pain here. All I ask is that if you tell me to do something please explain why. I can't follow blindly.

FYI...the advice I have received so far hasn't helped, but that might just be because I don't understand. As I said above, please explain
 
If he is taking his cpu out and it stays on like it should than his cpu is overheating. I would replace the cpu fan and if that doesn't work the cpu. That is hard because you may have a sensor on your motherboard that's gone wacky and causing it to shut down to protect the cpu.
Keep us posted,
Cindy [smile]
 
I am soooo confused. Can my CPU over heat in 3 seconds? Also, my fan is working just fine. It spins, very fast, and has for the 24 hours that I have had it.

If I haven't mentioned it before, this is a completely new system. I bought each part individually and put it together myself. The computer has never been on for more than 10 seconds and that was only a couple times when I had the CPU out. When it was in it has never been on for more than 3-4 seconds.

I am very confused over all this talk of my CPU fan. IT WORKS. Not only does it work, but it appears to be working very well. Can my CPU really over heat in 3 seconds?
 
Well, it certainly sounds like a CPU/Motherboard issue. We are focusing on the fan because it's a good place to start.

However, the most obvious problem is power. I'd first be suspicious that the Power Supply (PS) is bad but it helps to trace out all the potential power problems starting with the wall socket. Are there other devices on the circuit? Can you plug the computer into a different wall outlet on a different circuit?

What is the wattage of the PS? You should have at least 300W. Is the small switch on the PS set to 115V or 230V (this will depend on where you live)? Measure the output of the power supply with a voltmeter - 12V, 5V and 3.3V is what you're looking for.

If all this is fine, I'd guess that the motherboard is bad. A failing CPU won't turn the computer off (as far as I know).
 
Thank you for your post Accessdabbler. It is the first one that was really helpful! I'm going to babble here for a while and please let me know if my thought process is correct.

First off, my power supply is an Enermax EG365P-VE(FC) (350w). It is set at 115V and I live in the US. I'm having a hard time checking the voltage however. Either I'm not getting a good ground or the PSU isn't puting out power when it's unplugged. Since that doesn't make any sense to me I'm going to guess User Error on checking the Volt output.

Now, this is were I'm having a hard time figuring out if it's the CPU or the Motherboard. It could be the motherboard because he's the one that decides things. Especially the beeps that I am supposed to hear but do not. On the other hand, I have read about other (not this one inparticularly) Asus motherboards that wouldn't beep and they say that the mb and the CPU are not communicating so this is the result. This could happen if the CPU is bad.

In the end I'm 45/55 on if it's the motherboard or CPU respectively. The reason I am slightly leaning toward the CPU is that when it isn't plugged in the computer doesn't shut down. On the other hand, it still doesn't beep, so maybe that should be 55/45, motherboard/CPU. You see my dilema. I have been going back and forth like this every 10 minutes for the last 24 hours.

I guess in the end the only way to know for sure is to have some extra equipment to swap and test with. Thanks for the help!
 
If taking the CPU out lets power supply continue to work the PSU probably can't handle the needs of everything.
You have the classic symptoms of not enough power.
That said, you could have CPU or M/B pulling extra, but I think it is less likely than PSU.
Nothing specific that causes this feeling, just a hunch. Ed Fair
unixstuff@juno.com
Any advice I give is my best judgement based on my interpretation of the facts you supply. Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.
 
I am sure like everyone who has commented on this thread, the last thing I want is to be unclear so .

The CPU fan issue: most motherboards require a 3 wire fan to be connected to the CPU header, the reason for this is that some motherboards are designed to "shut down" if a fan is not detected and that is why I said some slower 80mm fans have a problem in being detected by the motherboard. point is just connect a 60mm 3 pin type fan to the CPU header to elliminate this possibility.

The CPU can indeed overheat in just a few seconds, infact if the heatsink is fitted incorrectly it often takes under 10 seconds to "burn out completely" I believe the Asus board has CPU overheat shut down protection (measured from the CPU core) as do several but not all of the newest boards.

PSU: When a power supply is failing it doesn't mean that it will just be "dead", I have seen many PSU's show similar symptoms to yours, they bring on lights and spin fans momentarily but are indeed faulty. Having said this the very fact that you have the excellent ENERMAX 365 watt leads me to believe that failure is doughtful (we use this brand and I have NEVER seen one fail!)

I did read somewhere recently of similar shutdown problems caused by the "overheat protection'" built into the new core and the motherboards implementation of this feature (sorry to be vague) I think it was an ASUS moby but a pre-production board being reviewed by Toms Hardware? ?? shouldn't really effect full production release's?
martin Please let members know if there advice has helped any.
 
Thank you Paparazi. Very informative and helpful.

I did have a comment for edfair however. I can't imagine how I could not have enough power. I am running Enermax's 350w power supply and at times the ONLY things I had hooked up were the case speaker, the motherboard, the CPY and the power switch. I can't see any way that this group would drain all the power out of my Enermax.

However, I do agree with what you said. Not enough power would possibly give the same symptoms as I am experiencing. I just don't think that is my problem. Could be someone elses however.
 
Found the following with a Google search:

ASUS C.O.P (CPU Overheating Protection) is a hardware protection circuit that automatically shuts down the system power before temperatures go high enough to permanently damage your CPU.
Constant, high-pitched noise generated from heatsink fans are a thing of the past thanks to ASUS Q-Fan™. The ASUS A7N8X with Q-Fan™ technology intelligently adjusts fan speeds according to system loading to ensure quiet, cool and efficient operation.

You said your heatsink fan was connected to a power supply connector instead of the mobo. That could be your problem. I would think you'd have to have the 3 pin type plugged into the mobo fan connector for the speed sensing circuit to work. The mobo must think you don't have a CPU fan.
Just a guess on my part. What does your manual say on this subject?? Please come back and let us know if your
problem is fixed and what fixed it!! [thumbsup2]
 
I had the same symptoms on a Dell Dimension with a PIII/733. The problem was a bad processor.
 
The manual is pretty slim. Doesn't tell you much of anything unfortunately. However, I had heard of such things on other Asus motherboards. I guess on my way home from work today I'll be stopping by and picking up a different 60mm CPU fan to see if that may be the problem.
 
Well a PSU can work but it doesn't mean it's working properly, I've seen hundreds of different problems ranging from the PSU burning out, not providing the Wattage it's supposed to, randomly turning off because the cable ties were in fact too tight......

It is always wise to replace a PSU to test in any situation where power might be a problem and the cause isn't immediately apparent. It often saves time in the long run and the last thing you want is a bad PSU kicking the cart and taking out other components with a bang and a flame coming out the back (also seen this).

If your fan appears to be running fine and is rated for your processor then I'd probably assume this is ok after double checking. Your motherboard is looking like a good culprit right now.
 
Just a small shot in the dark here, but check the reset button to make sure it is not jammed in a bit. I've seen some shoddy cases lately where this is happening. the power comes on for a bit but the machine won't boot and it never beeps at all no matter what you connect or disconnect because it is in a constant state of "resetting" .
Your problem is more likely to be that the MB doesn't recognize the fan with the wrong connector, but the reset problem is something to be aware of. It was only stuck in a bit and wasn't all that obvious to look at.
RocKeRFelLerZ
 
Funny you should say that. Someone else mentioned that in another forum. I disabled the reset button to ensure that it wasn't the problem. Besides, I spent $200 on this fricken case. It better not be defective :) I've seen stranger things however.
 
This is what I found on the Asus site regarding your motherboard
ASUS C.O.P (CPU Overheating Protection)

ASUS C.O.P (CPU Overheating Protection) is a hardware protection circuit that automatically shuts down the system power before temperatures go high enough to permanently damage your CPU.
It does seem likely that the fan must be connected to the connector provided for that purpose in order for the system to work...
RocKeRFelLerZ
 
I have the same prob, missed this thread and started a new one.{sorry} Not sure how to link it here. my post was titled "new system won't power up"

thread602-418231 no ideas, have tried exchanging cpu and m\board no help. have a ga-7va m\board with a boxed amd 2000+ cpu with fan. so fan should register with any onboard overheating support! have been exchanging parts with similar woking system to no avail!
 
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