System boots for 1 second, cpu fan spins, system shuts off, repeat.

[White Falcon]

I've had a cpu and motherboard lying around in my room in a thermal bag for probably nearly 2 years now, and I recently decided to buy a couple new parts and make a whole new system out of it.

Gigabyte P55A-UD3

Intel I5 760/stock fan

Corsair VS450 (Brand new)

Patriot 2x 4gb 1333 DDR3 ram (Brand new)

WD 2tb green hdd (Brand new)

Asus dvd drive (Brand new)

ATI 2gb 6950 (Not new, but has been in use in other system's crossfire)

------

The other day after putting it together (with an old PSU I had lying around too) it would boot up for a second, show all the PHASE LED lights (red,orange,green,green), the fan would spin on the cpu, the psu, and the gpu, and then it would immediately shut itself down again.

After trying it without the hard drive, the disk drive, the video card, switching around the ram, I decided it was probably an issue with the psu I had lying around, and as such I went to buy a new one.
After setting it up with that, the same problem is still occurring.

I'm hoping there's an easy/non expensive fix for this, as it seems to me that maybe I just left the cpu/mobo lying around for too long..

 

[Kaynar]

Do you have the button behind the mobo to CMOS clear?

possibly the mobo doesn't want to start because of bad RAM settings (old settings, new ram = incompatible?)

by switching around the ram I guess you mean you just swapped the new sticks around on the mobo's slots.

 

[White Falcon]

I don't have the button for it, But I have two pins on the board for cmos clear
It specifies: "Short - clear cmos | Open - Normal"

I've also got the ram kit I used to use on this motherboard (currently plugged into my current system)

Maybe that's the easiest test.

 

[Aquinus]

Do you have the button behind the mobo to CMOS clear?

This, clear the CMOS and test the PSU. It almost sounds like the system starts up (motherboard asserts power_ok) and as the system starts the motherboard sees a voltage outside of ATX spec and retracts the power_ok assertion which would shutdown the system immediately. I think you're playing with fire attempting to use that PSU. First of all you're working with two rails on a small PSU. Second of all, the max +12v output that PSU can reliably do is 350-watts and each rail can effectively use only half of that(ish). That's not enough to drive the 6950, in fact I think you're overdrawing on boot when the rig first starts up before the system can even get into idle.

Try a weaker video card or a stronger PSU.

 

[White Falcon]

Aquinas:
As I said, I've already tried it without the video card, not to mention the hard drive and dvd drive. I have a very basic ATI 4350 lying around aswell, it doesn't like booting with that either.
I also had the same issue with the 600w power supply that used to run this very system (same cpu/mobo)
Appreciate the input but I believe I've already established that it isn't the PSU or the GPU when I can switch them out and still replicate it.

Kaynar:
Attempted my old ram sticks, didn't work.. I'm unsure how I'm supposed to 'short' those two pins to clear the cmos, but I've tried numerous times to remove the battery to achieve that, as well as buying a brand new one and using that, still no dice.

 

[Kaynar]

:/

 

[Aquinus]

Maybe there is a short? If it's in a case can you build it outside of the case just for testing?

Also Kaynar is talking about CMOS clearing jumpers. There is sometimes a 3-pin connector with a jumper on two of the three pins. Switch it over should clear the BIOS unless you have a button for it instead. If you give me a minute, I probably could find it in your manual for your board.

 

[RCoon]

I'm unsure how I'm supposed to 'short' those two pins

Turn PC on, create a circuit between the two pins with a flathead screwdriver or a flat piece of metal and then remove the screwdriver/tool.

After that, remove all your F_PANEL cables, where the power button and reset buttons get plugged in. Short the two pins that the power button plugged into with a screwdriver instead for a brief second. If the F_PANEL power button pins are shorted permanently, the system turns off.

Check your mobo bottom isnt touching anything metal. I assume you've installed the brass standoffs inside the case?

 

[White Falcon]

Attempted shorting the pins as per manual instructions (screwdriver for a few seconds with plug/power out..

Aquinas: Unsure how I'd start it without the case button.

RCoon: This is from the gigabyte manual:

Always turn off your computer and unplug the power cord from the power outlet before clearing the CMOS
values.
• After clearing the CMOS values and before turning on your computer, be sure to remove the jumper cap from
the jumper. Failure to do so may cause damage to the motherboard.

I don't think I should do it with the system on..

 

[White Falcon]

Page 30 http://download.gigabyte.us/FileList/Manual/mb_manual_ga-p55a-ud3_e.pdf

 

[RCoon]

Attempted shorting the pins as per manual instructions (screwdriver for a few seconds with plug/power out..

Aquinas: Unsure how I'd start it without the case button.

RCoon: This is from the gigabyte manual:

Always turn off your computer and unplug the power cord from the power outlet before clearing the CMOS
values.
• After clearing the CMOS values and before turning on your computer, be sure to remove the jumper cap from
the jumper. Failure to do so may cause damage to the motherboard.

I don't think I should do it with the system on..

Try turning your PC on without using the power button. Short the power pins instead. They are the pins on the F_PANEL where your power button wire is plugged in.

Bottom left of that picture, multicoloured pins.

 

[Aquinus]

Page 30 http://download.gigabyte.us/FileList/Manual/mb_manual_ga-p55a-ud3_e.pdf

You beet me to it.


A button just completes the circuit, much like a screwdriver or any other conductive material.

 

[White Falcon]

Try turning your PC on without using the power button. Short the power pins instead. They are the pins on the F_PANEL where your power button wire is plugged in.

Bottom left of that picture, multicoloured pins.

Same problem

 

[RCoon]

Same problem

CPU Cooler installed properly? Thermal protection would cause an instant shutdown.
Check pins on CPU socket, could be a short there.

 

[Aquinus]

Same problem

Is it still in a chassis? If it is, take it out and build it on a table to ensure you're not shorting anything on the board that shouldn't be.

CPU Cooler installed properly? Thermal protection would cause an instant shutdown.
Check pins on CPU socket, could be a short there.

Not that quickly. A CPU still needs time to hit that thermal limit and when I had a C2D E6600 that took a good 10-15 seconds when I had that issue for the CPU to go from room temp to thermal (85*C or 100*C for that board at the time?) with the stock cooler with those stupid push pins that couldn't hold the cooler on right.

 

[White Falcon]

Is it still in a chassis? If it is, take it out and build it on a table to ensure you're not shorting anything on the board that shouldn't be.



Not that quickly. A CPU still needs time to hit that thermal limit and when I had a C2D E6600 that took a good 10-15 seconds when I had that issue for the CPU to go from room temp to thermal (85*C or 100*C for that board at the time?) with the stock cooler with those stupid push pins that couldn't hold the cooler on right.

How do you mean?

The short is starting the system, but only the same as the power button does. Wouldn't just entirely disconnecting it from the case's cables have the same effect as pulling it out?

 

[Aquinus]

How do you mean?

The short is starting the system, but only the same as the power button does. Wouldn't just entirely disconnecting it from the case's cables have the same effect as pulling it out?

NO! The "short" isn't starting the system. The short your making is completing the power on circuit which turns on the computer. The back of your motherboard could be coming into contact with the case which could cause a grounding fault or one of your standoffs might be making contact with the board in a way that created a ground fault.

There is a difference between shorting a circuit and a ground fault because of a short.

 

[White Falcon]

So do I need to completely remove the psu and mobo from the case, or just unmount the mobo and sit it atop something?

 

[Aquinus]

So do I need to completely remove the psu and mobo from the case, or just unmount the mobo and sit it atop something?

Just be safe and pull everything out.

 

[ne6togadno]

you guys remember that removing battery for 30+ secs when psu power cord is unplugged also clears cmos?

 

[crayolaoblongata]

Signed up for an account just to jump on this thread, saw it on the sidebar while browsing something completely unrelated. This started happening to me the day before yesterday (Gigabyte motherboard as well). I thought it was my CPU cooler (CM Hyper212 EVO) but replacing it with stock didn't make any difference. Will be keeping an eye on this one!

 

[rtwjunkie]

I have to second Aquinus on this. This sounds suspiciously like either a short on the back of the motherboard or a bad PSU.
Take it out and set it up on cardboard to rule out a short. If it still happens, can you use your other PSU and hook it up to see if it still happens?

 

[95Viper]

Yep, what Kaynar stated... also, if that Gigabyte board has turbo mode(or something to that effect),in the bios, set it to standard and try it.

Edit: Yep, sorry, still waking up. Ain't finish my pot of coffee.

 

[White Falcon]

Yep, what Kaynar stated... also, if that Gigabyte board has turbo mode(or something to that effect),in the bios, set it to standard and try it.

It boots for 1 second..

 

[micropage7]

It boots for 1 second..

so you have put it off from case and still run for one second? does it beep or something unusual?
have you checked all cables?
i suspect its from psu