Computer is dead, help please!

[Zario]

Hey guys, I figured you'd have some good tips on this. 

My computer just quit in the middle of the day yesterday and I can't get it to turn on again.  This rig with it's current setup has been running unchanged for about 3 months.  No power surge that I'm aware of.   

There is power to the mobo, and the light on the mobo is on, but when I hit the switch, no fans spin and nothing happens.  It's not the switch, because I've tried a couple different ones.  All cards and cords are connected solidly.

Did I blow my power supply, or can't I try something else first.  I don't have any extra 24pin psu's to test.  Thoughts?

[Kothnok]

Sometimes a fuse can blow, check to see if there is any on the mobo (doubtful) or in the power supply itself (sometimes).  Other than that, my only suggestion would be to get another PSU and hope it's nothing more serious.

[Avelandra]

could be a dead MB, sometimes a part may fail that can cause that kind of problem.

[TheGeneral451]

Same here guys, my WoW has been screwy and i can't get logged on, sorry about missing the raid    Give'em HELL!!!!!!

[TheGeneral451]

NVM finally got logged on and now i have a que, hopefully you replaced me by now

[dharq]

If you have a multimeter (volt-ohm meter), you can check the voltage coming out of the power supply. That will tell you pretty quickly if it's a bad PSU or not. I'd also check for heat damage. Is there any sign of heat damage/discoloration on the mobo?

[un4]

Also hit the reset button a few times to make sure nothing tripped your outlet.  Plugging a lamp or something in makes for a good test.

[Zario]

No discoloration on the mobo.  Outlet is working. 

Will a multimeter work if the PSU doesn't seem to be starting up?  I thought you had to be running under load to test.

[Avelandra]

PSU may be dead if you use the 4 prong V-Core line. If that's dead, the MB's LED will light up, but it won't start. This just came to me, though Im not 100% sure.

Also, the PSU will have to be on to use the multimeter.

[dharq]

Right, plug the PSU into the wall outlet, turn it on, and you should be able to test the line to the mobo even if the system isn't starting up.

[Zario]

Nice, thanks all.  I went out and picked up a DMM from Radioshack. 

I checked the 24-pin connector.  I'm only getting 4.15v from pin 4 and 5.15 from pin 21 which are both supposed to be +5v.  All others are 0.  I'm also not getting anything but 0 on my Molex connectors. 

New PSU ordered from newegg. 

[Zario]

  still no luck.  New problem.

So I got the new psu.  700w, 4 x 12v rails, good company yada yada.  Plugged it in, all worked well.  My computer ran well for 2-3 days with the wife playing a ton of Sims 3.  Then last thursday, it stops waking up from "sleep" which I thought was odd since I never use power settings that sleep or hibernate my computer.  Fans are running, lights are on, but it won't wake up.  Shutting down by holding the power button doesn't work.  So I hit the switch on the psu and pull the battery on the mobo. 

It posts and takes me to the bios.  Save settings and restart the boot process....nothing but the fans are running.  No beeps.  Holding the power button doesn't work again.  I have to cut the power again. 

So here are the symptoms I can find:
-Hardware monitor in the BIOS show voltages about 5-10% lower than reality.  I checked all pins on all rails with a multimeter and they're spot on. 
-Hardware monitor in the BIOS shows CPU temp and MB temp steadily increasing from 30's to 50C and ~55C respectively, then after the CPU hits 50C the computer "crashes" no matter what I'm doing.  I've never seen CPU and MB temps increase so steadily together--almost degree for degree.  Northbridge and CPU heatsinks aren't hot to the touch.  Screen blacks out and says no signal, but the fans and lights are on.  HDD light doesn't light up.  I didn't have heat problems for the ~6 months this rig ran before my last PSU blew up.  Nothing has been moved, unseated, bumped, unattached.  All fans are spinning as if all was normal.   
-Holding the power button to shut down works prior to it "crashing".  It does not work after it "crashes".
-I rotated through 4 different sticks of ram, no change.  Trying to boot with no ram didn't produce any beeps from pc speaker.

I'm thinking this mobo is shot and it's time to buy a new one, but I had two questions:
1.  Could there be any other culprits to these symptoms other than a fried mobo?
2.  Is there any danger to trying this test-one-piece-at-a-time troubleshooting?

[Docsamson]

Sounds like a dead mobo, definitely.  The first question would be if you're getting to the point where it's posting.  If you're not posting, and putting the right power in, then your mobo is dead, as that entire procedure happens before other components take over.

As for dangers and risks involved, there aren't really any.  Replacing good RAM in a bad mobo *could* fry the RAM, but if that's the case, you'd throw errors on the mobo as well.  In essence, any break in the chain is going to get noticed at the earliest point.

With the fact that you said the old PSU was mostly dead on all rails, I'd bet that you had a minor power surge, or some internal components in the PSU blew and caused damage to the motherboard in the process.

[Zario]

New parts are at home, but I've been in NYC for the week.  *sigh* I'll be back online someday.