STRANGE BOOT UP PROBLEM

[debasiskanhu]

My specs : -

Intel pentium d 2.66 ghz

Asus p5n-mx motherboard

1 x transcend 2 gb ddr2 667 ram

Mercury 8600gt 256 mb gddr3 graphics card

Samsung 160 gb sata ii hard disk
Sony 20x ata/ide dvd writer

Iball 400 watt psu

Intex 600 va ups

Recently i replaced my old motherboard asus p5gz-mx with asus p5n-mx. Everything worked fine for two days when suddenly after pressing the power button, computer did not boot and in turn turned off after 2 - 3 seconds. This problem then occured randomly, i mean after many tries it booted up and everything worked fine. After coming to desktop everything works fine and does not shuts down or restart on its own. Thinking it of bios problem i flashed the bios to the newest version available for the board from asus website. But in vain the problem persisted. I checked all my connections, took out my ram and cleaned it but it did not solve the problem. So decided to take my psu to iball service centre for checking it. They repaired it but still the problem persisted. Then i decided to replace it with a new psu because it had warranty but still my pc does not startup at one try. This problem is very random. I have tried to connect directly to power supply without connecting to the ups but still the problem continues. I have also noticed that the time when i push my power button my processor fan responds and rotates for that 2-3 seconds time span. Now i am confused..........don't know which component of my pc is damaged. Kindly help me out............shall be very grateful to any suggestions or tips. Thank you.

 

[GhislainG]

If you need help, please don't yell (which is what using all caps mean). Edit your message to make it easier to read and then you'll most likely get answers.

 

[jsc]

STOP YELLING!

Now - I tried to find the specs for the PSU in the Iball case. Couldn't. That tells me that it is probably a low spec PSU.

What is probably happening with both PSU's is that the 12 volt output is overloading, decreasing the output. This removes a control signal from the PSU called "PSGood" (or "PowerOK"). Losing this signal forces a CPU reset.

Unplugging all of the drives may reduce the load enough for the PC to boot.

 

[jsc]

STOP YELLING!

Now - I tried to find the specs for the PSU in the Iball case. Couldn't. That tells me that it is probably a low spec PSU.

What is probably happening with both PSU's is that the 12 volt output is overloading, decreasing the output. This removes a control signal from the PSU called "PSGood" (or "PowerOK" ). Losing this signal forces a CPU reset.

Unplugging all of the drives may reduce the load enough for the PC to boot.

What is the brand and model of the second PSU that you are trying?

 

[SizroSpunkmire]

STOP YELLING!

I think its because your caps lock key is stuck in the 'on' position...

 

[mtyermom]

Having caps lock on triggers an LED on your keyboard to indicate it being on, this is drawing just enough power to overload your PSU, thus losing the 'PSGood' control signal from the PSU.


...



I'm such an ass...

 

[debasiskanhu]

sorry guys i didn't knew that all caps means yelling as this is the first time ever i posted anything on a forum. i have edited my posting i think its alrite know.

 

[debasiskanhu]

TO JSC :-

the second psu was just the replacement for my first IBALL psu because it had warranty. IBALL is an indian company and might not be known in other countries.

i also suspect it to be a problem with my cpu power button or power wires ???

 

[GhislainG]

The power button temporarily shorts two pins on the motherboard. Since the cpu fan starts spinning when you press the button, it definitely works fine.

You replaced the PSU and it didn't resolve the issue, therefore I would suspect that the replacement motherboard is defective or something is not mounted/connected properly.

 

[Chrono_45]

I had the same problem a few days ago, so i took it to a store to get it fixed. They said that i had some bad memory, which caused it to restart or show nothing on the monitor. Hope that helps.

 

[debasiskanhu]

Hey guys back after a long time. actually I didn't get my problem solved..so decided to replace the P5N-MX motherboard and i got the new one 3 days back. but still the problem is continuing!!!
Ram Checked OK
Hard Disk Checked OK
Graphics Card Checked OK
PSU OK
Only left are Processor and my Cabinet.
Please Help!!

 

[debasiskanhu]

Also i have noticed one thing with my 4-pin ATX 12V Power connector...the one connected near the processor. I removed all my components except processor and then also the problem occured but when i removed that 4-pin connector, the problem didn't occur!! So I checked it for nearly 20-25 times and the problem didn't occur. but as soon as i put it back the problem starts occuring randomly. Also another thing I have noticed that this problem never occurs when I start my computer on back up mode of UPS.

 

[GhislainG]

Also another thing I have noticed that this problem never occurs when I start my computer on back up mode of UPS.

Are you using a UPS? Does the problem occur only if you connect the PC to the UPS? What PSU do you have and was the replacement PSU the same model? If the problem occurs only when using the UPS, what UPS do you have?

 

[debasiskanhu]

Also another thing I have noticed that this problem never occurs when I start my computer on back up mode of UPS.

Are you using a UPS? Does the problem occur only if you connect the PC to the UPS? What PSU do you have and was the replacement PSU the same model? If the problem occurs only when using the UPS, what UPS do you have?

The problem occurs even when I connect my PC directly to the mains without the UPS. The problem does not occur only when I connect my PC to the UPS and run in back up mode without connecting my UPS to the mains.

Do you have any idea about the 4-pin connector thing i mentioned becoz the problem does not occur when i remove it!!!
Obviously the boot screen does not comes up as removing that pin does not run my processor but still the computer does not shuts of on its own!!

 

[GhislainG]

The 4-pin CPU power cable has to be connected. Without it your system doesn't work, therefore it can't shutdown. Removing that cable doesn't resolve any issue, it just prevents the CPU from working.

Are you saying that if the 4-pin CPU cable is connected that the system works fine (it boots into the OS, etc.) as long as the PSU is connected to the UPS and the UPS is disconnected from the power outlet? Are you in North America? Have you tried a different PSU, i.e., not another Iball 400W PSU? What happens if you start the system with the PSU on backup power and then connect it back to the power line once the PC is up and running?

 

[debasiskanhu]

The 4-pin CPU power cable has to be connected. Without it your system doesn't work, therefore it can't shutdown. Removing that cable doesn't resolve any issue, it just prevents the CPU from working.

Are you saying that if the 4-pin CPU cable is connected that the system works fine (it boots into the OS, etc.) as long as the PSU is connected to the UPS and the UPS is disconnected from the power outlet? Are you in North America? Have you tried a different PSU, i.e., not another Iball 400W PSU? What happens if you start the system with the PSU on backup power and then connect it back to the power line once the PC is up and running?

I live in India. Yes ur right that when i connect my computer only through UPS the problem does not occur and also once started in backup mode and then if i connect to the mains, then also no problem occurs. Problem always occur only when i connect directly to mains or through ups when its connected to main power supply. For this reason I have done re-wiring of my house but still the problem continues.

 

[GhislainG]

I might be wrong, but the PSU most likely is defective, i.e., there might be too much ripple on the 12V. If you don't have access to a data scope to verify the stability of the 12V, then you should definitely try a different PSU brand/model.

 

[debasiskanhu]

I might be wrong, but the PSU most likely is defective, i.e., there might be too much ripple on the 12V. If you don't have access to a data scope to verify the stability of the 12V, then you should definitely try a different PSU brand/model.

Thanks for your reply..
I will definitely look into the matter and try out with a new PSU.
But as the problem had persisted, I have again submitted the mobo in the Service Center and they told me that it will take some time to check my mobo. So I will be back after a few days.
Thanks..
Thanks again for your assistance.