Motherboard problem or PSU malfunction?

[Lithography]

My desktop computer with a 6-year-old Antec MT-352 stop working. While power button pushed down, I can only see CPU fan and case fan tried to rotate, but immediately stop, and nothing happens after that.

However, if I unplug the microATX connector from motherboard, and push the power button again, both CPU fan and case fan are working fine.

Can someone enlighten me whether this is the problem of power supply or motherboard?
Could it be that power supply have some trouble to supply large current?

Thanks!

 

[JeffMD]

You removed the microatx connector? since the power button is on the motherboard, how did the psu do anything?

ANyways, it does sound like a short is sensed some where.

 

[Lithography]

The interesting thing about the motherboard is that it has some extra wires connected to the motherboard, which I think, supplies power for CPU fan and power supply button's reset functionality.

 

[pcgeek11]

Every time I have seen these indications

While power button pushed down, I can only see CPU fan and case fan tried to rotate, but immediately stop, and nothing happens after that.

it has always been the motherboard...

 

[Lithography]

Thanks for helpful suggestions. I guess it could be due to motherboard, and did the following experiments:

unplug ATX connection from motherboard, and push power button. Now every power supply voltage is correct (12V, 5V) when measured with DMM.

Then plug in ATC connector to motherboard, now, all connector voltage drops to 0V!!!

 

[fuzzymath10]

Every time I have seen these indications


it has always been the motherboard...

Same here, having had a couple of RMAs for that kind of thing.

The only time I've wrecked a PSU was when I purposely stuck a screwdriver into the fan vent to see how much noise it was contributing. Got a huge spark, blew the PSU, but the motherboard survived. That was stupid on my part.

 

[PhIlLy ChEeSe]

My desktop computer with a 6-year-old Antec MT-352 stop working. While power button pushed down, I can only see CPU fan and case fan tried to rotate, but immediately stop, and nothing happens after that.

However, if I unplug the microATX connector from motherboard, and push the power button again, both CPU fan and case fan are working fine.

Can someone enlighten me whether this is the problem of power supply or motherboard?
Could it be that power supply have some trouble to supply large current?

Thanks!

did you run it 24X7, if so then it's the PSU (over heated aged CAPS). List your full system spec's!