Random Refusals to Boot

[pullmyfoot]

Hey guys! Been a long time since I've been on these forums. Hows everyone (:

I was having some problems with a computer I built for a friend recently. The system works, but every once in awhile he cant boot it up. He said when that happened he would quickly switch off and on the power from the main plug and it would start up fine.

So logically, I thought the power supply busted. I helped him change it, twice within a few months. The second time was a week ago and today he dropped me a message saying the problem happened again and got a bit worse. Now it refuses to start for 5 minutes no matter what apparently.

I asked him to change the power adapter the last time to be sure so that is not the problem.

I really hope its got nothing to do with the mobo. Maybe its not grounded properly or something or plain faulty.

Anyone have anything else to suggest? Ive tried looking around Google but its hard to find a good answer.

Cheers!

[howste]

Welcome back PMF.

Does he (or you) have a UPS you could plug it into to see if it's a power quality issue?

[pullmyfoot]

nope. unfortunately thats what i am short of

[Steve R Jones]

but every once in awhile he cant boot it up

How far does it it get?
Was the system shut down properly before this starts?

[pullmyfoot]

It happens at random, and when it does it refuses to power on at all. Fans spin for maybe 1 second then bam, nothing. Thats when my friend used to quickly turn on and off the main power then it sort of jump starts it.

[Steve R Jones]

Pushing the power button and holding it an extra second or two would be worth a shot.

[electric]

sounds like a loose connection either at the receptacle [ wires ] or the
power cord at the power supply end isn't all the way in.

[pullmyfoot]

Thanks guys. Steve Ill ask him to try that the next time it happens.

Electric Ive changed the power supply 2 times, tried a different power adapter, even moved the whole thing to another room to get a different power socket. It cant be anything to do with cables as far as I can see.

Either its got something to do with the power going to the house or something after the PSU, which would be very annoying either way.

Just about running out of ideas.

[howste]

Try running it at your house or another location with a different power source for a while.

[JEROY]

You said you build it recently , but , did you put a used CPU ? ...And if so , how long is it in use ?

[pullmyfoot]

Will try that when I get the change this weekend guys. All new parts. It was about a year ago that I built it actually.

[pullmyfoot]

Hi guys, it wasnt a critical issue, more of an annoyance, so I only got around to checking it last week. I brought it back to my place and booted it 30 odd times over a week. Problem didnt happen. However I did manage to reproduce the issue when I restarted halfway through the boot and another time when I kicked the wire, both of which caused the computer to remain switched on but the screen and peripherals were not working. For my friend it happened on a random basis maybe every 3 or 4 times he switched it on, in which case quickly switching the main power on and off jump started it.

Last clue in the puzzle, thinking it was the PSU that was the problem, I swapped it out and left the new PSU outside the case and told him to try it for a week. No problems. This was a month back and nothing to do with what I described above. Thinking the problem was solved, I put the new PSU into the case, and the problems started happening.

Im starting to think its some grounding issue? I dunno anyone has any ideas? The PSU was grounded to the power socket at both houses.

[paul9]

The case doesn't obscure the mains input socket at all, does it?
I am just thinking that maybe his mains lead doesn't end up all the way in the socket.
Also, sometimes the wire conductors inside the lead can snap at the end of the strain relief section, so try with a new mains lead, too.

[pullmyfoot]

Nope. The thing which really bugs me is that there was no problem when the supply was out of the case

[wju425]

This kinda tell me something's with the orientation of the wires. Try this, put the PSU back in, unplug the power connector, give it a twist one full turn and plug back in.

I think it's a bad connection with one of the wire ends. Twisting it would put pressure on it.