New computer won't turn on!

MageBeowulf · October 17th, 2003, 04:07 PM

Hi,
Over the past few weeks i've spent at least $1000 on computer parts to build a new box now i've got all the parts. when I just had the mobo and the PSU I powered it up and it powered fine. Now I put everything in and it didn't power up. After getting frustrated I changed power cords. It powered up! What a sigh of relief. So I went to power it up again and low and behold no power up. The sleeper light is on and when I try to turn it on the fan on the CPU and the case fans jerk very slightly but there is no power on. Could this be a problem with the PSU? Its a 400W PSU that was on sale at newegg. But please tell me it isn't the mobo. I put that together so carefully you wouldn't believe it. Also when I powered it up with the processor and everything successfully the Dr Voice came on rattling off that there was no video card and keyboard/mouse etc. So i'm lead to think that it probably isn't the mobo. Does anyone have any suggestions?
Beowulf
P.S.
It is the Allied Power supply thats on sale for $33 and its the Aopen Nforce2 400 mobo.

Bill in SD, CA · October 17th, 2003, 04:10 PM

Welcome to TechIMO!

Are you able to test your voltages on the leads?

Bill

MageBeowulf · October 17th, 2003, 04:14 PM

I have a voltmeter here somewhere. Which lead should I be testing/how much voltage should I be looking for?

Oh and thank you for the welcome. I post on another forum that is the exact same layout as this one but no one could answer me properly so this place feels at home for me lol.

dafanman · October 17th, 2003, 04:17 PM

MageBeowulf
The most likely of things are:

If the mb powerd up outside of case and now once installed in case it dosent, then the mb is shorting out somewhere>>Did you use the standoffs ???

pull cmos battery, push the power button, and pull the power pulg, then replace cmos battery, and attempt to restart again while holding down insert key.

What all hardware is in the box, ram ammt, cpu speed, drives, ect....

Check the psu label what is the output for the 12,5,and 3 volt wattages???

Does the board require the 12v 4pin power, as well as the standard 20 pin atx power connector??

Best bet, after youve checked psu wattage, is to pull the mb out of the case, pull the hsf and cpu and clean both up real good with some isopropryl alcohol , reapply the proper ammt of heat sink paste, and reseat the hsf, making sure that its sitting square.

If more than one stick of ram try booting with just one, and a minimum of hardware.

***

rpertusio · October 17th, 2003, 04:21 PM

(EDIT: It looks like dafanman beat me to some points. I think he was copying from my screen

< suspicous >)

I have seen a few situations where the motherboard was actually shorting out on the case. Be sure that the holes (for the screws) line up with the holes/standoffs in the case. If you had accidently put a screw in the hole of the motherboard, but it doesn't line up with any hole on the case, the current will flow right to the case!

The reason it would only boot sometimes is because simply bumping the right component(s) will cause it to short out. If you get it to power on... try (gently) tapping on your components/mobo and see if you can isolate the area.

To test this, you could pull the motherboard and components, and put them on a non-conductive surface. (Some people use a piece of wood, or a telephone book, etc.) If the system boots successfully, then you probably were shorting out somewhere on the case. If you still don't get it to boot, start with the bare minimum, and gradually add each component, until you find the one that causes it to fail.

You could also make sure the voltage switch in the back of the power supply is not stuck at an 'in between' position.

Lastly, it's always possible that the power supply is underpowered on the leads. However, the usual indication is a boot-up with a 'blank' screen.

- rp

Bill in SD, CA · October 17th, 2003, 04:24 PM

To rule out the power supply you need to ensure that you're getting 3, 5, & 12V from the connectors that are supposed to be putting that out.

Bill

MageBeowulf · October 17th, 2003, 04:24 PM

The mobo was in the case when I first booted it up and yes I did use the standoffs.
I have:
Athlon 2800+ (Barton)
Corsair TwinX 3200 512 MB
Radeon 9700 pro
All the parts are brand new.
The board only requires the standard ATX 20 pin power connector.
I also have a Maxtor 120 gig/w 8 meg cache and a sony 16x DVD ROM.

Bill in SD, CA · October 17th, 2003, 04:25 PM

Good points rpertusio.

Bill

MageBeowulf · October 17th, 2003, 04:42 PM

Well I have a voltmeter and a diagram of the power supply connector. However I don't know what I should do with them since it seems to me that to measure the output voltage the power supply needs to be on and the power supply won't turn on.

dafanman · October 17th, 2003, 04:58 PM

Bugalaman
Im assuming the psu is still in the case,
Is anything connected to the psu, drives, mb, anything?

Did you: Pull the atx connector and reseat it?

Is the pwr, reset, hd led from case to mb correctly pinned?