Help with power problems

[FurBurglar]

I hope someone here can help me out with this problem. The power went out at my house one day and after it came back on my computer no longer powered up. Upon inspection, the power LED on the motherboard was still coming on but the computer would not power up. I used a paperclip to jump the power supply and it came on and powered the fans that were attached directly to it. I also tried hooking it up to an older motherboard with a 20 pin power connector and it powered up fine. I then tested it with another new motherboard with 24 pin + 4 pin 12v connectors and no power again. Again, the LED on the motherboard comes on but I fail to get the computer to power up. Any ideas on what might be going on here?

I also used a multimeter to check all of the voltages on the PSU and everything checked out fine.

 

[GalvanizedYankee]

*Puts on mind reading tin-foil beanie*

Your running an Aspire PSU w/o a UPS....Right?

You don't use a known good surge protector...Right?

You didn't unplug the comp and leave it that way until power was fully restored...Right?

The power outage was caused by a near by lightning strike...Right?


Did I score atleast 75%


...Galvanized

 

[FurBurglar]

I am running an Antec Neo 480 PSU

Power is running through a known good UPS and was at the time of the power outage

The outage occured while I was not home

The power outage was caused by a storm, yes but not a close by strike

Also, the 2 motherboards I have tried with no luck are an Asus A8N-SLI Premium and a DFI Expert. The board I used and got to power up was an old Shuttle AK31.

 

[GalvanizedYankee]

Consider this a bump: I have no idea...At all.

If all voltages are good but the PSU refuses to have two different boards POST *shrugs* IDK.


...Galvanized

 

[FurBurglar]

It seems kind of like the "cold boot" issue I have read about except the fact that I can't get either board to boot EVER.

 

[GalvanizedYankee]

Just an absolute guess...OK.

The Shuttle might be 5V dependent and your newer boards are 12V supplied.

Note: Even in stand-by some heat is being generated in the PSU. Now, sometimes, when capacitors dry out from age/slow venting, they will offer an open circuit when cold. Some old repair techs will warm a mainboard or PSU with a hair dryer to get them up and running for testing purposes only. You might be getting a 12V reading off your DMM but under the load of BOOT it's falling out of spec. If your PSU is out of warrenty, open it for inspection(venting caps). If it's still in warrenty, leave it out in the sun or warm it with a hair dryer on low through the intake grill, they try it again.

I've read several posts where guys have come back from vacation and the rig won't BOOT after being off, because the PSU cooled down. I had a PSU's 3.3V fall out of spec and cause RAM errors when ambients were <17C...Yep.


...Galvanized