Computer starts up for a few seconds, then shuts off

[wolfie1422]

Recently I started my computer as usual and proceeded to use it as normal, however suddenly it said 'shutting off' and proceeded to turn off. After this sudden shutdown, I attempted to reboot the computer to no avail. I then unplugged the computer and plugged it back in, and it would start for a few seconds spin everything up and shutdown. This seemed odd to me, and I retried the next day to see if it was temporary and it worked for an hour or so then shut down. At this point I assumed it was the power supply and purchased a new one. I put the new one in, and sadly same issue! At this point, I assumed it might be the CMOS, and attempted to pluck it out and reinstall it after 5 minutes, this oddly allowed my computer to work again for approximately a hour once again, however it soon crapped out once again. This seemed odd to me and I thought it was the CMOS battery failing, to which I canabalized my old computers CMOS to no avail. Before finally throwing in the towel, I tried to check each part for failure. I first unplugged the HDD, tried to boot, GPU, tried to boot, then each RAM stick, reboot, and none of this would allow it to run for more than a few seconds.

At this point im lost, I have no idea what the issue might be, anybody know any trick or have any ideas?

Many thanks,

Memphis-B Motherboard, Intel Core i7-4770, 12GB DDR3 Ram, GTX 1050 Small Form, 2TB HDD, Internal 460W Power Supply, Windows 10,

 

[Dark Lord of Tech]

Full specs would help.

 

[wolfie1422]

Full specs would help.

Whoops

Memphis-B Motherboard, Intel Core i7-4770, 12GB DDR3 Ram, GTX 1050 Small Form, 2TB HDD, Internal 460W Power Supply, Windows 10,

 

[Dark Lord of Tech]

What is the PSU? Delta?

 

[wolfie1422]

What is the PSU? Delta?

The new one is a Thermaltake 600W Smart PSU, I get the same result with it as the old one when I attempt to start the computer.

 

[mortemas]

Test the CMOS battery voltage. New ones should be above 3v. Maybe both batteries that you have are no good.

 

[wolfie1422]

Test the CMOS battery voltage. New ones should be above 3v. Maybe both batteries that you have are no good.

Since I don't own that device that lets you check that, I put the CMOS in another computer and it worked fine, just not on this one...

 

[mortemas]

Was it an old battery out of an old computer? You’ll never know if it’s a bad battery that way. All mobos are different. Maybe one works with a battery down to 1.5 volts and another works with a battery down to 1.2 volts. A new battery should be above 3 volts and will give you a definite answer to look elsewhere for the problem. How old are those batteries? Maybe it’s worth it to spend a few bucks to buy a new one and test it. If not, move on to try other things.

 

[Paperdoc]

I really doubt that a weak CMOS battery would cause this issue. What that can cause is a failure to retain CMOS settings, often leading to not knowing where to boot from. But to start up and run for seconds to maybe an hour before failing is something else. Your work so far suggests it is not the PSU.

One thing that MIGHT cause this is a poor connection on one pin of the CPU cooling fan to the mobo header. Pin #3 carries the fan's speed back to the mobo, and many mobos monitor that very carefully. IF the speed signal suddenly fails, some mobos will shut down the system quickly to avoid an overheating situation that damages that expensive CPU chip. Now, a failure of that speed signal can be caused by two things. The most obvious is: the fan actually fails to turn, or at least turns only very slowly, and the CPU DOES overheat. So check what temperature your CPU is running at, and whether it suddenly rises before the system shuts down.

The other possibility is that the connection where that fan plugs into the CPU_FAN header oxidizes over time and a poor connection results, causing the fan's signal to fail to reach the mobo. For this there is a simple thing you can try that often works. Shut down and open up. Locate the CPU_FAN header and the connector plugged unto it. Be careful not to disturb other things and disconnect something by accident. Now, unplug the fan from the header, then plug it back in again. Repeat several times. Make sure everything else is undisturbed and close up and boot up. See if that makes a difference.

What that does is "scrub" dirt and oxidation from the connector to restore the connection. IF that was the cause of your problem, that is a very simple zero-cost solution.

If that does not solve the problem, you'll have to explore other possibilities. Read up here on Tom's the troubleshooting process called "breadboarding". Basically you remove all components from your case and start setting up on a dry insulating surface like a board. You assemble first a really bare-bones system and see if it will start up cleanly. If so, you shut down and add ONE component, then try again. Eventually you may find that the system fails when the last new component was added, and you know the culprit. In your case, OP, since your system sometimes works for more than a few seconds, you MAY want to use longer periods of test runs before proceeding to the next added item.