Building PC ... Running in to some problems...

[Underwood]

I promised my friend that I would build her a computer so I went to Fry's last week and got all of the components, I built the PC, but I can't get it to turn on......

I don't have the specific model#'s for all of the components in front of me as I am at work but I can list most of the stuff...

-Pentium 4 3.0 Ghz w/ mobo package they had on sale
-160 gig Seagate HD
-1 gig Corsair 3200 RAM
-12x Sony DVD burner
-GeForce Video Card (don't remember the model#, it was $100)
-?X-finity? Case w/ built in power supply
-the other normal stuff, dvd-rom drive, floppy drive, sound card, etc....

I've gone through the Mobo manual and checked to make sure everything is hooked up correctly at least four times. The processor seems to be locked in place like it is supposed to be, and the Power Supply lights up as does the Power button on the case when the PC is plugged in. When I push the power button nothing happens... so what could be the problem?

My first thought is the motherboard... other than that I would think that it's either a problem w/ the case or the power supply. Any suggestions on how to fix this are greatly appreciated.

 

[mechBgon]

The most likely explaination is that the case's Power button wire is on the wrong pins on the motherboard. Sometimes the markings on the board are misleading. Here's a photo of an A7N266-VM/AA and you would think the silk-screened markings are saying the Power SW wire ought to plug in on the top row. But it was Backwards Day at Asus when they did the silk-screening or something So check the diagram in the manual for the location of the ATX Power Switch pins.

Also, I'm sure it's not something you really want to hear, but the low-class power supplies that come bundled with most computer cases are not usually that good. If the computer ends up working but not stable, definitely use that as an excuse to go pick up an aftermarket Antec SL400 or another high-quality brand of power supply like Enermax.

If you need more help, then post the brand and model of the motherboard and I'll help verify the right pins for your case's power button. A couple of other oversights I've seen builders make:

1) they don't put the motherboard on standoffs (see first four photos), they just bolt it straight down onto the metal motherboard tray. Baaaaaaaad idea :Q

2) they overlook their ATX12V cable

I also have a list of other no-POST/no-run causes here, the first link at the top. Good luck!

 

[Underwood]

Thanks mechBgon,
I'll take a look at the wires again and make sure they're in place correctly. I've got the other stuff covered, thanks again.

 

[mechBgon]

Sure thing Another couple of things to look out for:

1) the case's power button could just be faulty. When it's pressed, it's supposed to make momentary electrical contact. You can bypass the case's power button by using a metal object like a screwdriver tip to make momentary electrical contact between the motherboard's Power Switch pins, and the system should start just as if you'd pressed the case's Power button

2) Usually the button that you press is attached to the case's bezel (front face) and it in turn pushes the switch, which is mounted to the front of the chassis beneath the bezel. If the bezel isn't quite on all the way, then pushing the bezel's button may not sufficiently actuate the real switch underneath. So you might check that the bezel's definitely on all the way, and/or remove it and press the actual switch underneath as a fact-finding step.

Hang in there

 

[Underwood]

Ok.. I have a little progress ...

I had assumed that the color coded wires on the case matched the color coded pins on the mobo to hook up the start button etc.... needless to say upon closer inspection that was not the case.

Once I hooked everything up and hit the power the button the power came on but only for a second, all the fans spun then it cut out... I really starting to think that it's the power supply.

Any advice?

 

[mechBgon]

You might be right, it might be the power supply. Another possible explaination is a short-circuit. You might do a visual check to make sure the springy contacts on the rear I/O shield aren't getting into the USB or network ports, and unplug any case USB ports from the motherboard as a fact-finding step. Sometimes the pinout is different and then you can have a short-circuit there too.

 

[huesmann]

You do have this thing hooked up with only the CPU/RAM/vid attached to the mobo don't you?

 

[Underwood]

OK, I got everything working, it ended up being a short-circuit. One of the springy contacts was barely touching the LAN port and was causing everything to short out. Thanks mechBgon for all the help.

 

[mechBgon]

Originally posted by: Underwood
OK, I got everything working, it ended up being a short-circuit. One of the springy contacts was barely touching the LAN port and was causing everything to short out. Thanks mechBgon for all the help.

That's good news

 

[Somniferum]

That happened to me once -- I left one too many spacers behind the mobo. Was going to suggest you check for that but I see you figured it out.

Glad to hear you got it sorted out. :beer: