Help a first time building with computer

[JiGaNtO]

Me and my friend are building him a PC, neither of us have ever built one before.

Anyway so we seem to have assembled it fine, everything connected correctly as far as we could see
However when we plugged the power in n turned on the powersupply it began to emit a high pitch, anoying, whine that u sometimes hear from TV's or monitors. It was a 400 watt supply that came with the case, we went to bestbuy n bought an antec 350 watt n tried it and produced the same high-pictched whine.

the specs are

P4 2.4ghz HT 800mhz fsb socket 478
Albatron PX915P4C Pro it's a socket 478 pci express mobo
80 gig hd
DVD-RW
512 PC3200 DDR ram 1 stick
Radeon x700 256 DDR2 pro ATI express video card

was a 400watt Rosewill ATX case

As of now we pin pointed the problem to the fact that the motherboard power connector is 24pin while the power supply is 20pin, so we we're gonna try to find an adapter for it tomorrow. The auxilary power was connected n everything seemed fine.

Just wondering if the 24/20 pin issue is what's causing it, would that cause the psu to produce such a high pitched sound? The power would not turn on at all in the computer.

Any other suggestions would be greatly appreciated.

 

[mechBgon]

Welcome to the Forums The Rosewill 400W units seem to be getting bad results, which doesn't surprise me considering they're so inexpensive (or come in inexpensive cases). For the parts you've got listed, a good-quality 350W unit will do the job, but personally I like "overkill" in the PSU department

Anyway, since the extra pins on a 24-pin connector do help with power delivery for PCI-Express video cards, it may be that your guess is correct about 24-pin being the missing ingredient. I can also suggest a couple other things to check out: go to this page and then jump to Caseprep 2 page and make sure you got the board on the standoffs. And go to the Data & Power Cables page and make sure you got that ATX12V cable hooked up, too, people sometimes overlook that one.

Other than that, also look at the rear of the case and make sure the springy finger things on the I/O shield aren't getting into the USB ports or network jack, and unplug any case ports (USB, Firewire) from the motherboard for now, too.

Bigger picture: I hope you plan to give it another identical stick of RAM later so you can get the benefits of dual-channel (and double the memory, of course) Hope that's some help!

 

[JiGaNtO]

what kind of problems may result if the standoffs aren't put under the motherboard first; could that be a contributing factor in any way?

 

[Kasper4christ]

um, that could allow the motherboard to short out, because of the (typically) metal motherboard tray, making contact with the solder points on the mobo, could short
standoffs are screwed into places on the motherboard that arn't in contact with electricity,

 

[Fern]

Originally posted by: JiGaNtO
what kind of problems may result if the standoffs aren't put under the motherboard first; could that be a contributing factor in any way?

It won't work, and could fry hardware. Yes, IT IS a contributing factor

And since we can see you made some "obvious" first-time builder mistakes, have a look at mechBgon's site for first time builders. It's linked in his sig. Save yourself some time, headaches, and maybe money.

Enjoy the build and Good Luck!

Fern

 

[JiGaNtO]

so i did get the adapter today n it produced the same affect, so we put on the standoffs and well just as predicted it worked fine, because the the motherboard was in contact with the metal case it drew too much power overloading the psu hence the whining noise.

lol now i have an issue with a dvd-rw that we installed, all the wires are connected properly, however it seems as if it's not on, when we press the eject button nothing happens, nothing lights up. What i noticed is that the (for lack of knowledge of technical terms) the wide grey cable connecting from it to the motherboard has the inner wires twisted at one end, so i was wondering if that could be it. We haven't tested another CD-rom or another cable yet because didn't have any available at the moment. Any other things we could look for to find out why it's not working. Does something have to be enabled in the bios? the instruction manual that came with the motherboard isn't very good.

edit: heh i should read before i post, found all the answers in that guide, thanx for all the help, hope it goes smooth from here on

 

[mechBgon]

Keep it up, you're makin' headway