Sporadic failure to boot

phoenix

phoenix

New member
Every so often, I’ll turn on my PC, but nothing appears on the screen and the machine switches off and restarts itself after a few seconds, repeating the cycle until I
switch it off. If I unplug my computer entirely and leave it disconnected for several
hours, it usually starts up without any fuss.

What could be the problem here?
 
Start with the basics. Try another PSU.

Might be leaking caps getting hot and stuffing out. If ram modules weren't fitted right you'd have a continuous problem.

If it did so whenever the PC ran for a bit you might have cooling issues on the CPU, but the restarting points to the Power supply. I had an office pc that would randomly respond to being switched on ... or only come on 5mins after you pressed the ON button. Swapped out the PSU and all was well and the people rejoiced!
 
Voicy said:
Start with the basics. Try another PSU.

Might be leaking caps getting hot and stuffing out. If ram modules weren't fitted right you'd have a continuous problem.

If it did so whenever the PC ran for a bit you might have cooling issues on the CPU, but the restarting points to the Power supply. I had an office pc that would randomly respond to being switched on ... or only come on 5mins after you pressed the ON button. Swapped out the PSU and all was well and the people rejoiced!
Click to expand...

If the RAM was faulty, not plugged in correctly it would beep and not get past the POST. If it was a heating issue, it wouldn't restart immediately. To test though, leave it off for an hour or so. If it boots up and gets to your OS and then restarts it might be a heat issue.

First thing would be to test with another PSU as Voicy said, but if that fails, try another motherboard.
 
Thanks. Okay, so I'll buy a PSU and pop it in the next time this happens.

Rather the PSU than the motherboard.
 
Sounds like my problem. My ON switch was faulty and this would happen as well so atm my reset switch is my ON switch and my main ON switch is disconnected.

Yeah sounds like cpu overheating or power supply not coping anymore.
 
I had the same problem a few months back. Wouldn't start just that repeat cycle. Then it would start and work or start booting windows and freeze. Think before you start spending money just reset you BIOS, worked for me. Just taking out the battery doesn't always work. Depends on you motherboard.
 
What are caps, why would they leak and why would they only do so rarely?

Would it help if I took my power supply out and left it somewhere to dry next time this happens?
 
phoenix said:
What are caps, why would they leak and why would they only do so rarely?

Would it help if I took my power supply out and left it somewhere to dry next time this happens?
Click to expand...

Caps would be these or These. They would leak voltage/power because they might have been damaged, or the voltage suddenly reversed - but then a whole lot more would go wrong with the PC if the voltage was reversed. But do test with another PSU and tell us whether that works.
 
phoenix said:
Every so often, I’ll turn on my PC, but nothing appears on the screen and the machine switches off and restarts itself after a few seconds, repeating the cycle until I
switch it off. If I unplug my computer entirely and leave it disconnected for several
hours, it usually starts up without any fuss.

What could be the problem here?
Click to expand...

Okay go into the bios check under the system health or maintenance, go to the temperature monitor... You will see you system is set to shut down at a specific temp see if system is gets close to that temp and then shuts down. That would immediately incate cooling problems on the CPU...

If it goes into a loop cycle and is not overheating, then get this http://www.memtest.org/#downiso and download the dos iso and it will tell you if your memory faulty.

If that is fine check your PSU as previously advised

If you still having a problem disconnect any extras you have connected to the bored and start and individual boot on each part...

Check if any capacitors are blow on you pci cards if installed, and on your motherboard..

If problem persists check your harddrive.
 
How do I check whether a capacitor has blown? Will there be obvious burn marks?
I am surprised that my machine would still work if any capacitors had blown.

/Note to self: find out what capacitors do.

Thank you

Update:
I checked temperatures in the BIOS:
CPU temperature varied between 34 and 38 degrees C
System temperature varied between 40 and 43 degrees

Memtest could not find anything wrong with my RAM.

I tested my hard drives' SMART status using UbuntuÅ› Disk Utility this evening.
No errors there either.
 
Last edited:
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