Computer will no longer turn on

Bill Turnip

Bill Turnip

Bill Turnip

Associate
Joined
1 Oct 2020
Posts
1,251
Hi all

Last night, our estate's electricity supplier were doing something with their cables, and seem to have accidentally replaced a live cable with a neutral, and as a result half of our house has blown up! Having loss adjusters round later to tot up damage, but I wanted to see if anyone knew the best way to test a PC which is no longer turning on.

No plugs have changed, and the electricity is now back to normal. Is it most likely to be just the PSU that has failed, or is it possible that other components have fried as well? I don't have another PSU to test, and won't be able to get one in time unfortunately, so it's more of a general question if anybody has had a similar experience. I have all receipts and everything, so I should be able to claim for each part (Not sure how a loss adjuster is going to replace a 3080), but want some idea if I'm likely to have to replace everything.
 
PC PSU's aren't sensitive to input polarity, because they always rectify it to DC.
In fact in countries with symmetrical mains plug/socket, live and neutral will change position depending on which way you connect plug to wall.
Though if it's some old especially not so great PSU, power cut from work could have been "the last straw breaking camel's back".

But if PC was connected to other things breaking, it's possible something came through them.
For example lightning strike into phone line might cause surge through LAN connection frying motherboard.
 
Thanks for getting back - everything the pc was connected to is still working which is a relief. I suspect it is just the PSU which is borked as it was a voltage issue through the mains. It's a corsair rm850x, and only a year old so can verify the purchase which is fortunate (in case I get someone who doesn't know what they're looking at). The power guys have agreed to pay for a replacement now so that's a relief, but if it's the whole pc I'll be gutted.
 
Who knows if those erroneous jobs also caused some overvoltage.
Having neutral wire disconnected/missing would only prevent current traveling in single phase system.
Multiple phases is different and in three phase powered industrial facilities etc missing neutral can do damage easily.


If you have multimeter you could try checking if PSU itself isn't entirely dead.
In good old time with colour coded wires before Corsair excreted this all black crap fad it would have been simple thing:
Purple was 5 Vsb and should exist always when PSU is connected to wall and has switch in on position.
And connecting green PS-ON signal to any of the ground pins would have given PSU signal to start allowing checking other voltages. (orange 3,3V/red 5V/yellow 12V)

Now you have to go through all hoops and always count pins in every phase.
https://help.corsair.com/hc/en-us/articles/360025085372-How-to-Test-a-power-supply-unit
 
Why don't you just claim for the entire PC?

Your not hurting anyone, it'll be through the power companies insurance and I'm sure they can cover any increase in premium.

Basically, in short, if it were me I wouldn't feel guilty at all just claiming the entire PC back.
 
Esat, thank you for your advice, but they've already okayed a replacement.

Not claiming for the whole pc as if its just the PSU I'm happy to replace and carry on. Also, I'd imagine replacing a 3080 is basically impossible, and I don't want them to just try and repay the rrp as that's probably the worst scenario.

They've agreed for me to purchase and fit a replacement psu which should be here tomorrow, so that will either solve my issue or open up a whole new world
 
V F said:
Would a surge protector have protected it?
Click to expand...

Oh, possibly. However, I've saved my brightest moment for this tale. A few months ago I mentioned that we should get a surge protector for the computers, so I went out and bought a couple. When it arrived, I dutifully plugged everything into the surge protector, thinking "What a clever little grown-up I am".

Monitor? Check.
Speakers? Check
Toothbrush charger? Check
PSU? No. LET'S LEAVE THAT IN THE NORMAL SOCKET.

I'm a moron, and a lesson has been learned...
 
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