Computer not POST-ing, but is powered on

[TeacherTim2]

Recently built a Intel computer and it ran for about 7 weeks without any trouble. In the last 2 weeks now, I've run into a strange boot-up problem. When I press the power button on the front of the computer, the power supply kicks in, the fan inside the power supply comes on along with the fan on the CPU. I think the Hard Drives power up and spin, but can't be totally sure about that. Either way, the HDD activity light on the front of the case does not blink. The monitor does not display anything, and the computer does not respond to any key-presses on the keyboard, nor does it even beep. I can't even turn off the computer by holding the power button on the front...I have to switch it off with the power switch on the back of the case/power supply.

It will boot on occation (maybe once every 3 or 4 times I cycle the power), and I've never run into trouble with the computer freezing or locking up on me.

Any ideas? My guess is the motherboard. I've also thought it could be a video card issue too, but not sure. Here's my computer hardware list:

Case: Antec Sonata w/ included power supply (I think 380W)
Motherboard: Asus P5GD1 Intel 915P ATX
Processor: P4 540J Prescott 800 MHz FSB LGA 775 3.2 GHz
Memory: OCZ Premier Value 1GB (2 x 512MB) DDR 400 PC 3200
Video Card: Sapphire Radeon X300 128 MB DDR PCI Express x16
HD: Seagate Barracuda 250 GB Serial ATA 150

Any ideas? Just bought this all from NewEgg on July 6th, so shouldn't have any warranty issues.

Thanks in advance! Let me know if you need more info.

 

[anandtechrocks]

I too recently built an Intel computer for a family member and it has the same problem you posted. I have not had a chance to look at the PC yet, but because I installed a cheap power supply, I'm guessing that is the problem. If you have a multimeter try to test your power supply's output.

Specs:

Intel 530J
Intel 915 Mobo
Corsair DDR 512 MB
Integrated GFX
Seagate HD

 

[mechBgon]

That motherboard is designed for an ATX 2.0 power supply. You might want to switch to a quality ATX 2.0 unit (stock Sonata 380W is not ATX 2.0). The overall situation does sound like it could be the power supply not getting the job done.

 

[TeacherTim2]

Not that I'm doubting either of you, but I read this from Antec's site regarding the PSU:

What kind of power supply is in Antec?s Sonata case?
Sonata ships with a special TruePower ATX12V-standard (backwards-compatible to ATX 2.03 and ATX 2.01) power supply which is AMD? and Intel® compatible and will support any ATX motherboard that is also compatible with any of those standards. This power supply has been further specially engineered to be even quieter than Antec's already-quiet regular TruePower series of power supplies.

I don't mind buying a new power supply, and would certainly like one that is quieter. I even looked at the SeaSonic S12-430 before I bought this case. But $100 it a little stretch right now.

Drop the cash on the power supply? Thanks again in advance!

 

[mechBgon]

Originally posted by: TeacherTim2
Not that I'm doubting either of you, but I read this from Antec's site regarding the PSU:

What kind of power supply is in Antec?s Sonata case?
Sonata ships with a special TruePower ATX12V-standard (backwards-compatible to ATX 2.03 and ATX 2.01) power supply which is AMD? and Intel® compatible and will support any ATX motherboard that is also compatible with any of those standards. This power supply has been further specially engineered to be even quieter than Antec's already-quiet regular TruePower series of power supplies.

I don't mind buying a new power supply, and would certainly like one that is quieter. I even looked at the SeaSonic S12-430 before I bought this case. But $100 it a little stretch right now.

Drop the cash on the power supply? Thanks again in advance!

If your Sonata has a 20-pin main ATX power plug, then it is not ATX 2.0. If it has 24-pin, then it might be ATX 2.0, although there's more to the ATX 2.0 spec than just the 24-pin cable. Anyway, you might open the case and confirm the exact model of PSU it's got, and post that. Sorry to ask a silly question, but you did have the ATX12V secondary power cable connected as well, right?

 

[TeacherTim2]

My Sonata power supply says TruePower 2.0. 380W. Model TPII-380. I'm guessing it's this power supply.

I have a 24-pin power plug plugged into the motherboard (it's 24 pins, but 2 of the are "break away"). I also have the secondary power cable (also a 4 pin cable) plugged into the motherboard.

And I'm a teacher...there are no silly questions.

Thanks again for the help! Any ideas?

 

[mechBgon]

My next un-silly question is whether you have the PSU's little RPM-monitor wire connected to the motherboard, the one with a blue wire and a black wire. This is a long shot, but I remember my Asus A7N8X refusing to boot if it had a low-rpm case fan hooked up to its onboard headers. Easy to test and eliminate the possibility, anyway

Your Sonata must've come from that time window when they had 380W but also ATX2.0. I hope it isn't the PSU gone bad

 

[TeacherTim2]

I do have the black and blue wire attached to the motherboard. I also have the fan for the processor plugged into the motherboard.

I also have the included Antec 120mm case fan plugged in, but it's plugged directly to the "Fan Only" labeled power connection directly from the power supply.

If the PSU died, I'd think it will be covered under the warranty, right? Guess that's the next thing to check w/ Antec. Except I bought it from Outpost...

 

[mechBgon]

My point was that you should unplug the blue-&-black wire as a fact-finding step, to see if its RPM signal is so low that it's making the motherboard . Easily tested, at any rate

 

[TeacherTim2]

Well, oddly enough, it's working now. I've powered off, then on, probably 12 times, and it works just fine. The first 2 times I did get it to power on, the Ethernet card didn't work (it's built-in the mobo), but now that's working fine too.

Hoping it continues to work!
Tim