PC Diagnosis (not powering on)

I think the fact you managerd to get into Windows for 2-3 minutes suggests the motherboard is more or less fine. The PSU sounds as if it's taken a bit of a hit and can't provide stable rails.

Was the rear fan powered by the PSU either directly or indirectly by fan controller?

I'd be testing a new PSU right about now. Always worth having a spare kicking about for such eventualities.
 
are all the power connectors secure into hard drives, gfx card motherboard ?
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I've removed / replugged them a few times, they seem to be as secure as possible.


I think the fact you managerd to get into Windows for 2-3 minutes suggests the motherboard is more or less fine. The PSU sounds as if it's taken a bit of a hit and can't provide stable rails.

Was the rear fan powered by the PSU either directly or indirectly by fan controller?

I'd be testing a new PSU right about now. Always worth having a spare kicking about for such eventualities.
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The back case fan is plugged directly into the Mobo (no fan controller) in the CHA_FAN2 connection.

About 1 in every 3 attempts it'll manage to boot into Windows for 2-4 minutes but then shuts down completely. The other 2 attempts it'll just run the fans full blast for 30 seconds and shut down.

Is changing the PSU still the next recommended step? If so on Monday I'll order that Antec I mentioned earlier.
 
Yes indeed. I'm a little concerned that a motherboard fan would stop like that though. It's most odd.

Grab the Antec PSU and keep the next replaced Corsair as your spare. Corsair are generally good PSUs but even they fail sometimes.

Had a PSU last year that was fine for 8 weeks and then developed a nasty habit of cutting out anytime between 10 seconds and after a few minutes of operation. I just put in my spare and it the rig worked fine from thereon. I didn't test the PSU in much detail but I suspect the rails were instable and this caused the safety circuits to withdraw power from the PC when one was loaded and dipped.
 
I would say the surge protector is at fault here, is it not there to protect your computer from these situations.

Is the PC still plugged into the surge protector, or straight into socket on the wall. Thinking the surge protector is knackered now, (you could try claiming off their insurance).
 
freddie64 said:
I would say the surge protector is at fault here, is it not there to protect your computer from these situations.

Is the PC still plugged into the surge protector, or straight into socket on the wall. Thinking the surge protector is knackered now, (you could try claiming off their insurance).
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It's plugged into a different surge protected in a different room/wall socket so unfortunately I don't think it's that :(. I don't have any idea where I purchased the surge protector nor do I have the receipt so I don't think I'd be able to claim off their insurance.
 
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If its a POP, itll be a PSU capacitor. The power surge will have sent too much voltage into teh cap and itll have blown off the board in the psu breaking the circuit. My son had this when he wa at unit. The MoBo will be ok, as their is a break in the circuit when the cap blew off the board, all you ahve to do is replace the psu and itll all be ok... seen adn dealt with this a thousand times. theres no point in tyring to plug and unplug various stuff and watching the fan spin then stop, the less the psu has to drive it will power on, but the bios and the MoBo needs ALL 42 caps on all 4 rails to power up. If theres one missing, the rail link is broken, therefore only giving you a fraction of the required power to power up to full boot capability... Chang the PSU and youll be fine. Ill put money on this one if im wrong...
 
Just wanted to check something before I order a new power supply in a minute.

I disconnected the PSU from the motherboard and jump started it with 3x HDDs and 3x Fans connected, it has been able to power them without shutting down (for the 30 minutes I tested it for anyway). Does that indicate it might not be the PSU... or is it because the load isn't high enough?
 
3 HDD and 3 Fans would be less than 20 Watts. Your system would be 150W+ at initial load, maybe more. Hard drives wouldn't be too fussy about input voltage either, they'd probably run ok at 11v/4v or 13v/6v whereas your PC wouldn't so well.

Besides you'd need to load it up a lot more. About 10x G4 20W bulbs in series would be about equivalent I guess.

This is of course assuming it's the 12v rail that's damaged. Could be the 5v just as easily.
 
Tealc said:
3 HDD and 3 Fans would be less than 20 Watts. Your system would be 150W+ at initial load, maybe more. Hard drives wouldn't be too fussy about input voltage either, they'd probably run ok at 11v/4v or 13v/6v whereas your PC wouldn't so well.

Besides you'd need to load it up a lot more. About 10x G4 20W bulbs in series would be about equivalent I guess.

This is of course assuming it's the 12v rail that's damaged. Could be the 5v just as easily.
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Thanks for the reply (again)! I'll just order up the 'Antec TruePower New Modular 650W' (should arrive Monday), then I can be sure if it's the PSU.
 
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Well, the power supply arrived today. The first boot shut down after ~2 minutes, the second boot ran for about 30 minutes and then shut down. Looks like the power supply took out other components with it. Short of building a whole new computer (which I can't afford) I have no idea what to do now :(.
 
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Tbh i would clain off my house insurance, a £50 hit is better than paying for a new pc. this is my uncle done and he got a better spec, just make sure u have old psu in. if you had a surge protector then u can claim off them. no matter what you house insurance should cover it, just say u were shutting it down as the power surged.
 
After testing a bit more it seems to be the motherboard, it was connected via ethernet to the router when the lightning hit so it appears to have damaged it. The strange thing is I've plugged a network cable into the port and the computer has now remained stable for 2 hours (and hasn't yet shut down). The ethernet port doesn't work at all anymore (the activity light stays solid green), device manager doesn't even show the motherboard has a ethernet port.

...anyone got a spare socket 775 motherboard for cheap? :p
 
maybe worth a look in the members market if you have access.

tried looking for the requirements but couldnt see them anywhere :(.
 
PaulM said:
Well, the power supply arrived today. The first boot shut down after ~2 minutes, the second boot ran for about 30 minutes and then shut down. Looks like the power supply took out other components with it. Short of building a whole new computer (which I can't afford) I have no idea what to do now
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Unfortunately, a PSU was replaced only on wild speculation. A power 'system' consists of many other parts. For example, the power controller determines if a PSU even powers on. And when it powers off. Sound like your problem? Only way to know the state of anything in a power system (before even disconnecting one wire) is one minute labor and a multimeter.

To have an answer means obtaining that £7 solution from ******. Touching a probe to six wires. Then posting those three digit numbers here. Next reply will immediately identify a suspect without wild speculation. And learn how computers really work.
 
westom said:
Unfortunately, a PSU was replaced only on wild speculation. A power 'system' consists of many other parts. For example, the power controller determines if a PSU even powers on. And when it powers off. Sound like your problem? Only way to know the state of anything in a power system (before even disconnecting one wire) is one minute labor and a multimeter.

To have an answer means obtaining that £7 solution from ******. Touching a probe to six wires. Then posting those three digit numbers here. Next reply will immediately identify a suspect without wild speculation. And learn how computers really work.
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With the new power supply (after plugging in / removing an ethernet cable) it has been stable for over 24 hours, although the ethernet/lan port on the motherboard seems to be fried. We tried the old PSU in somebody elses computer today and their pc shut down almost instantly (same as mine did), so the old power supply seems to be damaged too anyway.

I probably have a multimeter somewhere, so if you'd like to post what I should test and which readings I should give that would be good, thanks. I don't pretend I know anything about computer hardware, the only reason I built the computer is because I wanted to pick quiet parts.
 
PaulM said:
I probably have a multimeter somewhere, so if you'd like to post what I should test and which readings I should give that would be good,
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Set the meter to 20 VDC range. Black probe connects to the chassis. With the computer off, touch the red probe to a purple wire where the PSU connects to the motherboard. That should read about 5 volts. But the number may contain additional facts. Post all three digits.

Next measure the green wire both before and as the power switch is pressed. Behavior as power turns on also should be noted. Do same for the gray wire.

And finally, setup the machine for maximum load. For example, read a CD-Rom, while downloading from the internet, while playing complex graphics (ie a movie), while powering a USB device, while playing sound loudly, while searching the disk drive, while ... Now measure any one red, orange and yellow wires. Report numbers from all six wires.

Maybe repeat that with the 'defective' supply in another system to better learn why damage happened.

Apparently this system deletes the word "M a p l i n" since we need to be protected from company names.
 
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