No power after installing new mobo and CPU

DoorTech · October 5th, 2002, 02:50 AM

Hi
I've just installed a new motherboard and processor. When I push the power button on the front of the tower no fans turn on no noise nothing. What I have noticed is the power led flashes for a second and so do the led's on the keyboard, the mouse's infra-red led stays on until I push the switch on the back of the power supply.I've checked all my connections several times. I have a Gigabyte motherboard GA-81GX,Pentium 4 1.8 processor fan came with processor, ATi "All In Wonder" 4X 32MB DDR AGP DVD- H video card, new 30 GB Maxtor HD, new sound blaster sound card, the power supply is 300w ATX 12v switching power supply. I've made sure my video card is 1.5 volts because of the Intel chipset on motherboard. I appreciate any advice. Thank you

**Whir** · October 5th, 2002, 03:01 AM

Sounds like something is hooked up backwards. Have you tried reseating the CPU? Check the back of the mobo to make sure it's not touching metal anywhere and shorting out (those little brass standoffs are bad for that). Check the RAM to make sure it's seated properly also. Let us know how it goes.

Welcome to TechIMO!

-Whir

daveleau · October 5th, 2002, 03:17 AM

Welcome to TechIMO!

Make sure the jumper for resetting the CMOS is set to the correct position.
Make sure the power switch is attatched correctly.
Try holding the button in for afew seconds. Sometimes they can be touchy. Sounds wierd, but I have had a system do this and it was the power button. There was either a short or the connection was bad. I had to hit the power button 2-3 times to get it to work...

DoorTech · October 5th, 2002, 03:17 AM

I'm sorry I should have said I tried those suggestions. I have those little brass standoffs I made sure every one had a hole on the motherboard to screw to. I've tried reversing the wire's from the power switch on the front of the tower to the motherboard, because I can't tell which is + or - they are green and black when they are install with green being + I get the led's to flash for a second reverse them and I don't. So I'm pretty sure that connection is right. I'm stumped. I really appreciate your reply.

**Whir** · October 5th, 2002, 03:19 AM

Check to make sure your hard drive ribbons on are on the correct way?

DoorTech · October 5th, 2002, 03:23 AM

When you say make sure the jumper is in the correct postion I'm not sure what you mean. I see the CMOS pin there is not a jumper on it I thought it was just for clearing the CMOS. Should I have a jumper on those pins in the off postion?

daveleau · October 5th, 2002, 03:24 AM

The only other thing is the mobo might be grounded. Anything else would at least get you into the POST and then mess up.

I suggest removing the mobo and reinstalling it if the above does not work (the CMOS jumper is the best guess, I think). If all else fails try another power supply. If that checks good, then get a new mobo (return this one

)

Good luck
Dave

DoorTech · October 5th, 2002, 03:25 AM

I just checked the ribbions for the hard drive and they are in the right postion but thanks I hadn't checked that.

daveleau · October 5th, 2002, 03:28 AM

The jumper should be 3 pronged with one prong with nothing on it and the other two having a jumper connecting them.

Like in this picture: http://www.ttmicro.com/JUMPER.JPG

The pins are numbered 1,2,3. If one and 2 are connected, like in the pic, all is ok. If 2 and 3 are connected by the jumper, then the CMOS is set to reset when power is supplied.

The red power light usually flashes on for an instant when the CMOS jumper is set incorrectly (or when you set it to reset your CMOS settings).

DoorTech · October 5th, 2002, 04:00 AM

Dave
Sorry it took so long to reply but I have only one monitor and I had to dissconect. I thought for sure this was going to get it. I set the jumper to 2 and 3 for normal and it still didn't work. I appreciate the suggestion.