Computer fails to power up

David Bisset · 29 Jul 2013 at 11:04

Hi all,

I've been asked for help by someone who has a computer that takes many presses of the power button to boot. I've yet to physically get at the machine so to date my knowledge is limited, but was wondering if anyone has more of a clue than me (not hard!)

The computer (about 18 months old):
i3-2100
Gigabyte Z68AP-D3 Intel Z68
Sapphire HD 6670
WD Caviar Blue 500GB
Corsair 4GB (2x2GB) DDR3 PC3-16000C9
Corsair Builder Series CX 430W V2
Win 7 home premium
Nothing overclocked as far as I'm aware

The problem:
Some times the computer starts first time, runs without a hitch. Other times pressing the button doesn't cause it to start.
Edit: Apparently sometimes its first try, sometimes second or third, but other times is like the 45th try...

By not start: No fans spin up (not even the PSU) but a green light on the mobo does come on. No bleeps are heard, no post screen seen or anything.

Tried so far: reseating the RAM, swapping the power & reset buttons around.

Not yet tried but will be when I have access to the machine: Take one ram stick out, start a bunch of times. Try other ram stick likewise. Replace the PSU (I have a spare of the same make/model of PSU kicking around). Dropping the RAM speed/loosening timings.

Anyone got any thoughts/feelings about what this is likely to be, how best to diagnose/fix it? As its an inconsistent error I'll not be certain it is working as intended with a bunch of restarts

which makes life much more annoying.

wazza300 · 29 Jul 2013 at 11:07

tell him to swap over the front panel power button wires on the motherboard with the front panel reset button wires and start the pc with the reset button

just to rule out a faulty front panel power switch

Shadz · 29 Jul 2013 at 11:09

If there is an overclock on the system sometimes they can fail and cause the machine to
not boot up properly, I would start by removing the overclock if there is one and seeing
what happens then.

Failing that I would be checking the PSU as if there is no power then that has to be a
problem some where along the lines. Also the green light on the motherboard is normal
most boards have a green light to show they are getting enough power going through it
mine will go out and a red led will come on if there is not enough power through my board.

Idleman · 29 Jul 2013 at 11:40

Shadz said:
If there is an overclock on the system sometimes they can fail and cause the machine to
not boot up properly, I would start by removing the overclock if there is one and seeing
what happens then.

Failing that I would be checking the PSU as if there is no power then that has to be a
problem some where along the lines. Also the green light on the motherboard is normal
most boards have a green light to show they are getting enough power going through it
mine will go out and a red led will come on if there is not enough power through my board.

As he has an i3 2100, I don`t think overclocking is the issue.

I would follow wassa300`s advice before doing anything else. And while you have the side panel off, check all power and data cables are properly seated.

David Bisset · 29 Jul 2013 at 11:48

Already switched the buttons around I'm afraid

would have been nice but no joy. I'll reconnect all the power cables anyway when switching out the PSU - I'll redo the data cables at the same time just in case.

A bit of googling has suggested that the i3 2100 IMC may have difficulty with 1600mhz ram, so I'll check what it is running at and drop it to 1333 if its at 1600 - I think the performance hit won't be noticeable

wazza300 · 29 Jul 2013 at 11:50

it should run 1600mhz ram without any trouble,but you can try at 1333mhz

could be power supply,if it's not that maybe a mb fault

DaleTheWhale · 29 Jul 2013 at 11:53

Board shorting on the case stand offs?

Try the board outside the case, I had this issue before, would run and then short other times.

David Bisset · 29 Jul 2013 at 11:55

Not a bad suggestion Reaper

I'll try taking it out, can do that without any extra bits so a free check

alias86 · 29 Jul 2013 at 11:55

reset the motherboard?

i have had the same issue was the motherboard in the end.

In the past i ve had a broken fan cable causing a short. luckily had the stuff to fix it.

David Bisset · 3 Aug 2013 at 17:52

So it looks like the information in the OP was slightly wrong - the mobo flashed a green light but it went out again. PSU failed the paperclip test, just sat with fan twitching for a minute before finally starting so have replaced it. Also turns out the system spec was wrong! Looks to be working fine with replacement PSU, thanks all for your help

Edit: Argh, PSU ~2 months out of warranty, first got asked about the problem 3 months ago but wasn't able to go visit. Ach well, low-end PSU anyway so no great loss, just frustrating!