mb has power but drives dont turn on

[DjJake]

Okay I am building a computer for my brother and have encountered some difficulties.
It has:

Iwill kk266
1ghz thunderbird
seagate 30gb harddrive
sparkle 300w power supply
geforce sdr
256mb generic 133 ram


When I push the power button the green motherboard light comes on and the fan turns but the HD, CD, and floppy do not come on and the monitor does nothing and I have to turn off the power supply to get the computer to turn off. Every few tries it boots perfectly and runs fine. What could be the problem? Could it be the power supply? Or maybe the motherboard? It is very wierd since it does work sometimes.

Also when it goes to sleep it stays asleep until I reset it.

 

[PowerMac4Ever]

What revision is the mobo?

Are your drives hooked up to the psu for power?

Can you turn the computer on through the computer case's button or just the psu?

 

[DjJake]

mobo is v1.2 bought from fry's a week ago. Yes they are hooked up to the psu for power.
I don't know what you are getting at with that last question. The power supply has a switch in the back to turn on and off its source of power but this does not turn it on. Pushing the case button turns everything on. To turn everything off I usually have to turn off the psu switch.

 

[Kartajan]

Not too sure as to the problem's source, but I have 1 piece of knowledge that you may find useful. Every ATX Power supply that I have seen does hard shutdown after holding the "case" power switch depressed for 10 seconds by default.

I would probably go back through again to ensure that all power connections were firmly connected, to include the "soft power switch" and reset switch on the case.

 

[kenthuang]

Frys? Theres your problem!!

 

[Maetryx]

It almost has to be the power supply. Unplug the mobo from the power supply and then turn it on. You should find that the hard drives and the CD-ROM *still* don't work all the time, proving that the mobo has nothing to do with it.

If you have a spare hard drive, try it out too, just to double check that you don't happen to have a dead hard drive *and* a dead CD-ROM. But I'd bet money your power supply isn't putting out enough amps.

 

[aa_koch]

Well, unless it's a problem with the power supply, could it be that the mainboard is causing a short-circuit somewhere? I had a friend who had exactly the same problem, and although I told him about this he said everything was installed correctly. When he went to return it to the store, the guy took a look at it and said it had messed up because of... a short-circuit.

I suggest you remove the mainboard from the case completely, and start from scratch. If necessary, use nylon stand-offs if available.

 

[DjJake]

thanks for all the help!