No power from PC after electric surge

vygec

vygec

vygec

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The electric went in the whole house. since then the PC, wont switch on. ive opened up the case, disconnected the CMOS battery and unplugged the power from the PSU to the motherboard. left it for a minute or so, and plugged all back in again, no change :(

Anything else i can check, or do i have a busted PSU!!

Ta.
 
vygec said:
The electric went in the whole house. since then the PC, wont switch on. ive opened up the case, disconnected the CMOS battery and unplugged the power from the PSU to the motherboard. left it for a minute or so, and plugged all back in again, no change :(

Anything else i can check, or do i have a busted PSU!!

Ta.
Click to expand...

have you checked the fuse?
in psu lead and extension lead if used
 
My crap PC has survived many power-cuts, it has a really bad PSU from a bad brand... Surely yours must be ok? I don't know how you would sort this out. But I do know this...

... buy a surge protector!
http://www.overclockers.co.uk/showproduct.php?prodid=UP-040-AP&groupid=702&catid=55&subcat=

Edit: On second thoughts, I have heard of some PSU's having timers in them to prevent powering up after powercuts... how long has it not been working? The timer (if any) should only be a few minutes, I think.
 
i tried a different power lead, and plugged this straight into the mains. this had no effect either
 
The fight over surge protectors is a bitter one. The informed consensus seems to be that they're a placebo, but they make people feel happier.

Only stopping by to say that you could have a dead psu. Or motherboard. Or psu and motherboard. Or psu, motherboard, cpu, ram, graphics card and hard drives. Electrical storms suck, I wish you luck
 
Could try removing all power leads from the pc, plug a fan into one of the molex connectors and link out pins 13 & 14 on the main 24 pin ATX connector, switch the power on the power supply or mains socket and see if the psu starts.
 
RJC said:
Could try removing all power leads from the pc, plug a fan into one of the molex connectors and link out pins 13 & 14 on the main 24 pin ATX connector, switch the power on the power supply or mains socket and see if the psu starts.
Click to expand...

just an update, i just tried this. the fan powered up!
however when i plugged everything back in again, no response from the unit.
does this mean that the psu is ok?
 
vygec said:
just an update, i just tried this. the fan powered up!
however when i plugged everything back in again, no response from the unit.
does this mean that the psu is ok?
Click to expand...
yep ,not sure if that tests the power good signal though
 
Nah. It means that the psu isn't totally knackered. Doesn't follow that the psu is ok.

Can you beg/borrow/steal a different supply to try the system with?
 
:D sorry mate i wasn't to clear
it looks like it is providing power but
the psu sends a power good signal to the mobo and if this isn't sent the pc will not start
even with no power good signal sent you can still read the power on each rail 12v , 5 v etc with a multi meter

what i was trying to say is i don't no if when you jump the main power plug it will send power whether the power good signal is there or not
 
Unplug the psu, take out the cmos battery and clear cmos. Leave for a good 30 minutes and then test, has worked for me twice before.
 
vygec said:
just an update, i just tried this. the fan powered up!however when i plugged everything back in again, no response from the unit. does this mean that the psu is ok?
Click to expand...
It means the power supply may be perfectly good or may be completely defective. It only means the AC power plug was attached.

A power supply can illuminate lights and spin fans - and still be completely defective. The only way you can 'see' a power supply good or bad is with a 3.5 digit multimeter. 30 seconds and numbers from that meter mean the technically informed can point to the few or one suspects in the very next reply. Did you know about the power supply controller? Did you check that? Of course not. It determines whether a power supply turns on. And the only way to know what it is doing is to use a multimeter.

You have two choices. Either get a multimeter so that the most knowledgeable can reply constructively. Or just keep replacing parts until something works. The later means replacing many perfectly good parts and putting hardware at greater risk. Your choice. Get definitively answers immediately or buy new computer parts on wild speculation.
 
Flick the switch about a bit. It did the trick on some shoddy PSUs I once had. Mobo 12V needs be connected for it to power up.
 
ok, i borrowed a multimeter from a friend.
hmm..what do i do, never used one, what to connect where and do what, and what am i looking for?
 
vygec said:
ok, i borrowed a multimeter from a friend.
hmm..what do i do, never used one, what to connect where and do what, and what am i looking for?
Click to expand...
Set the meter to 20 VDC. Clip the black lead to chassis ground. View the connector where power supply connects to the motherboard.

First measure the purple wire. A three digit number around 5 volts. That number must exist even when the computer is off - anytime the computer is connected to AC mains.

Repeat that measurement on the green and gray wires both before and as the power switch is pressed. Take notice of how voltage changes on each as the power switch is pressed. Gray wire should take a second longer to respond. Again, record and report those three digit numbers.

Third, measure any one red, orange, and yellow wires as the power switch is pressed. Ideally, these should rise up and be stable. In your case, maybe not. What does each do? What is their final value?

Post those numbers to have a definitive answer. A description of what you just viewed will be included - to learn from the experience and to appreciate what happens in there.
 
someone please help!
i picked up a new psu (corsair hx650), just plugged in with the same result as before.. no response from unit. ive only plugged in a hdisk, and discarded everything else, but no response.
any ideas on what is causing the problem, im wondering whether its the mainboard now?
 
Does sound like your motherboard has failed, only other thing is to remove the board from the case and test it with minimal components.
 
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