Intermittant "Power up" Fault

[nimagraven]

Hi all,

On 23rd December my Seagate harddrive "died".. When I say it died, it was having an intermittant problem where it was spinning up and not being detected in BIOS (Consequently, nothing would boot and POST would freeze).. It was intermittant as sometimes I could get into Windows.. And I immediately backed everything up.

I replaced the harddrive definitely thinking it was a harddrive issue and noticed that my PC was then having issues restarting from Windows. Monitor would go black and not detect a signal, yet everything was spinning.. Fans, HD, keyboard init etc.

The new harddrive was unfortunately littered with bad sectors and kept cropping up with horrid problems on eventvwr until eventually it was freezing the system and crashing it.

So.... I got the harddrive replaced. Installed Windows and verified through eventvwr that everything "appeared" to be working normally as far as I can see.

Now I noticed that a) my reboot issue is still there and b) it's also having the same problem starting from a VERY cold start (though let me stress NO HD detection issue now). The only way to fix the issue is to completely power down by holding the power button and powering up again (though this intermittantly helps it sometimes).

There are no beeps from the mobo, everything turns on, except I noticed the keyboard LEDs "freeze" and go no further. I see no POST.. Monitor stays black before going into standby through not receiving a signal.

I checked all the power coming from the power supply and it "appears" to be fine. I flashed the motherboard last night to see if that fixed the issue (it didn't).. So obviously I am boiling it down to a piece of hardware.

I've not run memtest86 yet, but my question to you guys is... Would you put this down to the mobo or the power supply or neither of them?

Obviously, I would like some opinions as it's hard to diagnose for me on my own and it could be a costly thing!

Thanks a lot in advance for your help .

[smargh]

I'd say PSU or memory. Or perhaps one of those, plus maybe the pure anti-luck of getting a knackered new HDD.

How did you test the power supply? Did you use a multimeter? What PSU is it, how old is it? Have you tested the cables to make sure the molex/sata connectors aren't dodgy?

You mentioned "cold starts" which kinda points to knackered capacitors, but that could be a red herring.

I would guess at a knackered PSU. I had one HDD [probably] killed by a bad Tagan power supply not delivering enough voltage.

edit:... but also check for swolen/leaking caps on the motherboard. Which motherboard do you have?

[nimagraven]

Not tested it with a meter yet.. But was planning to. My dad has a meter and was asking him about it this morning (he used to use it when working on components in old VCRs).. He wasn't confident that it would pick up stuff from the power supply (not sure why he said this .. He gave some reason but will pester him tonight .. )

PSU is a silverstone (from memory! I'm at work so can't really check!). I think it's 800W (or there abouts) and is around 1 year & a half old.

I thought it might be capacitors, but it's one of those is it.. isn't it :-/... The mobo is a MSI K9N SLI Platinum..

At least if I run the memtest over night tonight I can rule out memory ...

I changed/reseated most stuff when problems first came up, I didn't swap SATA cables (don't have one lying around spare) .. But doubt that would really cause the issues with the resetting/cold starts?

Thanks very much for your help

[peterb]

Is it a SATA disk? If so have a good look at the data connector. They are pretty flimsy (IMHO) and somer flimsier than others. I had a similar problem which turned out to be a small crack in the plastic housing so that the connection was intermittent. Solution was simply to replace the cable.

[nimagraven]

Left Memtest86 running for 16 hours.. 11 passes and no faults.

Checked the capacitors on the motherboard and they seemed fine.. No bulges and no junk coming out of them.

Semi-stumped. I'll try the graphics card under load and see if I get any kind of crash to occur - just to be sure to rule that one out as well.

[vaughan]

if you're having intermittent problems like your computer will not boot when pressing the power button, but will actually boot up after you press ctrl-alt-del, then it's likely that the power Good signal from the PSU (+5v) is at fault and that your PSU is of poor design or the power good signal is not at the correct voltage (should be +5v +/- 5% tolerance or better)

[whoops]

I have had similar intermittent problems dating back a long time, just put it down to not booting up correctly, service packs etc, I now know that there is no need at all for these sort of things to happen, as I changed PSU, and it is like a new system.

[watercooled]

If you have another computer in the house, try swapping out components. Don't forget that if you're using OEM versions of Windows, it won't boot off another mobo, though (I could be wrong).

[nimagraven]

Hard/soft boot doesn't matter. I get the same issue.

At any rate, I bought a new PSU so will see how that goes.. If it's not that then it's just tough luck.

Thanks all .