New PC won't power on

[Raven]

The components just arrived today, and I put the PC together.

When I press the power button, the PC powers up for about 3 seconds, then shuts down.

I only have the motherboard, CPU, RAM, and video card installed.

It looks like something power or heat related.

The PSU is a Fortron 400W, which should easily power just a X2 5200+ Windsor, nForce 570 board, and 8600 GT.

The problem is, I don't have another compatible PSU to test with.

It could also be the CPU overheating.
I removed the heatsink, double checked to make sure I got any safety stickers off the bottom. I also cleaned off the compound, and added a fresh layer.

The fan is turning, the HSF is on snugly and properly, I don't know how it could be the CPU overheating.

Any suggestions?
Tomorrow I'm trying to find another PSU to see if I can't rule anything out.

[Darth Wong]

Unfortunately, problems like this are most easily diagnosed when you have a healthy supply of spare parts to swap in, to find the faulty component through a process of elimination.

One thing you might want to try doing is removing the RAM and video card. A MB with no RAM on it will beep an error code instead of booting up, but at least you can tell it's working that way.

[Superman]

Errr... So you are getting some power from the power supply?

[Beowulf]

The PSU connected correctly? There may be more than wire bundle needed. Also, make sure the RAM and video card are firmly inserted into the appropriate slots.

[SCRawl]

The components just arrived today, and I put the PC together.

When I press the power button, the PC powers up for about 3 seconds, then shuts down.

I only have the motherboard, CPU, RAM, and video card installed.

It looks like something power or heat related.

If it's only powering up for three seconds, I can't see how it might be heat related. That just isn't long enough for the CPU to get hot.

I agree with the Sith Lord -- drop the RAM and video card, and count the beeps (if any) that ensue. You might then be able to look up the fault, if it's available online.

You might want to get out your multimeter and check the output from the power supply, and further that it's properly connected to the MB.

[Ariphaos]

Some of the newer PSUs are really picky about the load they're under. Though I've usually only seen it with the fancier ones, rather than cheap models like that.

[Raven]

Errr... So you are getting some power from the power supply?

Yes, the motherboard has a green LED that detects when power is connected. Also, all the fans (CPU and GPU) spin, until everything cuts out after a few seconds.

If it's only powering up for three seconds, I can't see how it might be heat related. That just isn't long enough for the CPU to get hot.

This is a little encouraging. Hopefully, this is the case, since I'd rather have a faulty PSU than a burned out CPU.

I agree with the Sith Lord -- drop the RAM and video card, and count the beeps (if any) that ensue. You might then be able to look up the fault, if it's available online.

You might want to get out your multimeter and check the output from the power supply, and further that it's properly connected to the MB.

The same thing happens (no beeps) with no RAM and video card.

Power connectors are all connected, snugly.

I'm going to try another PSU tomorrow as well as borrow a multimeter.
I can also swap in a different AMD motherboard/CPU, but I'll have to pick up a heatsink/fan for that.

[Superman]

I once had something similar happen; it turned out to be a simple matter of having the tower's power button connector plugged into an LED slot (what do you call that prong thingy?). Sounds like yours might not be quite as simple...

[Ace Pace]

This is a dumb question, but is the motherboard mounted? In other words, did you remember to put in the standoff screws to prevent contact with case?

[Raven]

Goddammit! RTFM!

Beowulf had it, there was another 12V 4-pin connector I missed. It was located on the opposite corner.

This is a dumb question, but is the motherboard mounted? In other words, did you remember to put in the standoff screws to prevent contact with case?

Yeah. Stupid cheap (lopsided, too) case came with a whopping 2 of those hexagonal screw thingys. Luckily, I found a stash of spare screws.

[Datana]

Goddammit! RTFM!

Beowulf had it, there was another 12V 4-pin connector I missed. It was located on the opposite corner.

Yeah, that threw me for a loop, as well. My latest system's mobo required a 12V 8-pin connector in addition to a 24-pin connector and a 4-pin molex, when my previous one only required a single 24-pin connector. The Fortron 500W PSU I had ordered came with only a 4-pin connector, but I was able to find an adaptor easily enough. The 12V rails and wiring are supposed to be stable enough on this model of PSU that it can handle the increased current pulled by the eight pins, but I'll still be keeping a very close eye on things for the next month or so.

[AdmiralKanos]

Goddammit! RTFM!

Beowulf had it, there was another 12V 4-pin connector I missed. It was located on the opposite corner.

First rule of computer assembly: never leave an important-looking hole unfilled

[Raven]

First rule of computer assembly: never leave an important-looking hole unfilled

Heh.
It looked so innocuous.
My last computer was a socket A 4 years ago, so I've never seen that additional connector before.

I actually have Superman to thank for it, though.

I was sure I hooked up the power button correctly. I also knew that wasn't the problem because the second thing I tried was shorting the power button jumpers with a screwdriver.

But I went back to the manual just to look at the front panel wiring anyway, and there it was: additional 12 V power connector.

Leave no important looking holes unfilled, indeed.