[SOLVED] PC died and won't start anymore (power button does nothing)

[jtoelli]

Was playing a game on my PC during bad weather and suddenly the PC died due to a very short power cut (house lights and pc monitors flickered on and off for like a second).

Now the PC won't start at all (power button does nothing) but the wall socket and monitor has power again.

Switching the PSU on/off causes the motherboard components LED's to flicker but no fans moving and no MOBO light indicators or sounds.

The lan port light blinks normally while PSU is switched on and so does the headphone controller connected via USB so they seem to get power through the MOBO?

Is the problem PSU or MOBO or both?

 

[cdrkf]

Was playing a game on my PC during bad weather and suddenly the PC died due to a very short power cut (house lights and pc monitors flickered on and off for like a second).

Now the PC won't start at all (power button does nothing) but the wall socket and monitor has power again.

Switching the PSU on/off causes the motherboard components LED's to flicker but no fans moving and no MOBO light indicators or sounds.

The lan port light blinks normally while PSU is switched on and so does the headphone controller connected via USB so they seem to get power through the MOBO?

Is the problem PSU or MOBO or both?

It's hard to know for sure - its possible the power cut caused a voltage spike that damaged something. The PSU is closest to the main electrically so would be the first thing to try.

That said before doing anything else it might be worth trying a full reset of the machine - that is remove the mains from the PSU, and pull the cmos battery (usually a coin cell). Leave the machine like this for ~ 5 mins to allow all capacitors to drain. Then put the battery back in, plug it back into the wall and see if it will start.

Note doing this will clear the bios settings so if the machine does start up you will need to go back into the bios and adjust settings again (e.g. enable XMP profile for the memory).

If the machine is still dead, you can also try a minimal boot - remove all buy 1 memory module and graphics card from the machine. If the machine still won't start then you will need to test with a different PSU

 

[DavidM012]

The problem was no surge protector.


The PSU is now suspect and everything in the PC is now suspect, although depending upon the specifications of the machine and how much power went thru it at the time of the power fault.

Things that probably survived: CPU and Ram, drives.

The cooler most likely survived, if it's an air cooler. Unless it's an AIO (all in one liquid cooler) and the pump also bought it.

GPU is suspect if it is a particularly high powered modern one of those.

Mobo is indeed suspect.

So what were your system specs?

Cpu:
Cooler:
Mobo:
Memory/Ram/Dimms:
Drives:

Chassis/case:
Optional fans:
PSU make, Model, wattage and age:

So you could try switch off the mains, press the power button a few times to drain residual power, wait 5 mins and clear CMOS by clearing the clear cmos jumper pin and putting it back, or removing the cr2032 coin battery for 30 seconds.

Maybe by a fluke it's still working. Someone really fussy might say, no, take out the power supply completely, test it somehow (like test the outputs with a multimeter, see youtube for that) or buy a completely new power supply since you simply can't trust it after a power fault:

You can decide the level of risk, anxiety or danger you wish to face. Obviously buying a PSU without knowing if anything's working is a risk.

Taking it to a PC shop to look at is probably about the same cost as a new power supply. So it's whether you want to do the troubleshooting or delegate to a pc technician.

If you take it to a shop maybe they're gonna go 'it's fried, mate' and it'll be (whatever components we have in stock to replace with). Parts and labor in other words. You save on the labor if you're savvy enough to do it yourself. And you can select what new parts you want if you order online if necessary.

I would hazard crowdsourcing opinions could give you a few pointers if you do nothing in haste. It's hard to see how anyone could make it worse since you probably already tried to turn it on and off a couple of times. Though perhaps not impossible.

 

[DavidM012]

Also the GPU is hard to test in another machine if it's now fritzing since they do have lots of watts going through them so it could potentially also fry any other machine it's tested in.

So don't test on anything you can't risk. Like sometimes it's handy to have spare hardware but also costly sometimes you wish there were useful diagnostic tools but this is really where the hard haggling self build approach can fall down.

There should be some diagnostic tools that a technician would carry and use for customers in a while-u-wait workshop which would make some choices easier but, if all you've got is like, 'an old mobo' well that mobo could be so old as to not be capable of running a modern gpu anyway and fry in the effort of testing, for example. And you don't want to risk any good hardware on it either.

So the designation 'suspect' is basically, risk attached in attempting to test. There may or may not be a fault, but do you feel lucky enough to find out?

 

[jtoelli]

Both of your suggested clearing CMOS so I did that and that magically fixed all issues.

After removing the CMOS battery and leaving it out for 5 minutes then plugging it in again it fired up like nothing was ever wrong and the PC works normally again.

Thanks for the help!

 

[DavidM012]

Glad to hear of a survivor! Do take the extra precaution of a surge protector and have fun.

 

[cdrkf]

Both of your suggested clearing CMOS so I did that and that magically fixed all issues.

After removing the CMOS battery and leaving it out for 5 minutes then plugging it in again it fired up like nothing was ever wrong and the PC works normally again.

Thanks for the help!

Glad we could help - as David mentions surge protection is something to consider. You might want to look at buying a surge protection power strip and plugging your machine into that, rather than directly into the mains. Hopefully should prevent this happening again.