PSU? Motherboard?

[dbonniwell]

10 days ago, When I press the button to boot up my computer and the compter lights inside the unit flash on momentarly as do the cooling fans and shuts right off. Less than a second.

5 days ago I pressed the button again and the computer booted up and ran normally.

Today it was back to flashing on and turning right off. I can hold the button in and it does this in succession on off on off etc.

I took out the sound card video card and unplugged everything that draws power except the CPU and the same thing on, then off within 1 second

Motherboard is a 790i by EVGA
PSU is Silverstone OP850 Watt
This unit is not that old, not that many hours on the build.
Any ideas?

 

[Tmagic650]

Power supplies are easier to replace than motherboards. Try this first...

 

[dbonniwell]

I pulled the powersupply and put it on another computer and it worked fine
Now could it be the MB or the off on switch itself. I would like to test that switch by rigging up another to see if that works, if the same problem, then do they sell plug in on off switches?

 

[Tmagic650]

The switch is a momentary contact kind of switch, as long as you can connect it to the motherboard header you should be okay. You can test the motherboard by shorting the pins where the old switch connects to the motherboard. Just touch the pins with a small screwdriver and quickly release. If the motherboard starts up, the switch is bad. If it doesn't start up the motherboard is bad

 

[mailpup]

Another way to test the switch is to "switch" the wire leads with the Reset button. They both work the same. Use that as a spare button to test with.

 

[Tmagic650]

Yes, I forgot that one

 

[dbonniwell]

Sincere thanks for your help,
I shall do so, I also found a button on the MB itself and can try that too. Sorry I did not know this button existed till now
I will report back the results
Now I sit here thinking "Now why didn't I think of that" about the switch

 

[dbonniwell]

I plugged in the reset switch to the start switch post and while I was puting it back together I would plug in one thing and try plug in another and try till I had it fully assembled and it worked that day.
then the next day, same problem. EVGA told me to ake the mother board off completely and put on card board or wood and try. I already had it down to near barebones as you can get and it happened. Any other thoughts out there?

 

[Tmagic650]

It has to be the motherboard

 

[dbonniwell]

Thoughts exactly, Now to convince EVGA. Thanks for your assistance, Disregard the line through my typed words

 

[Shiney]

Try resetting the bios, check cmos battery

 

[dbonniwell]

Thanks for your reply
Actually the thing will start up today. Not sure about tomorrow though and the machine never moves
I checked the battery with a volt meter and it was at 3 volts and I reset the CMOS
How often are those batteries changed out? I have had this thing run just fine for over 4 years now

 

[Tmagic650]

CMOS batteries can last between 1 and 6 years... or longer