Building new PC, Mobo has lights, but no power!? 2

[webcats]

I'm building a new Athlon XP 3000+ with an Asus A7N8X Deluxe mobo and 512mb ram. I have a new case and I'm transferring all the other components from my old PC (Athlon 600Mhz). I have a 300 watt PS that was working fine in my old PC.

Now the problem: When I put it all together and hit the power switch in the back of the PS, there are 2 lights that light up on the mobo. 1 is the power indicator and the other is the AGP warning light(?). Anyway, when I hit the power switch on the front of the case, nothing happens. I tried reversing the 'power sw' lead from the case to the mobo but still nothing. I checked and it doesn't look like the mobo is touching anything which could be grounding it. I even put all the pieces back into the old case, but with the same results. Anyone have any ideas? I'm stumped! Thanks.

 

[muthabored]

What brand of power supply do you have in the new PC? Perhaps your power supply is giving enough power...

 

[webcats]

Hi, the power supply is by Sparkle Power, 300 watt. Thanks.

 

[micker377]

The leads on the "power switch" go either way. Are you sure they are plugged to the correct pins? I'm not being sarcastic, I've seen MoBo production changes that weren't reflected in the manual - read the board itself. Pull everything except CPU and memory. Turn on - do you get any "beeps"? If you do, shut down, then put in video board. Try again. If you get anything on the screen ("boot error&quot, anything, shut down and try floppy and hard drive. Continuing on - one thing at a time until you find the problem. By the way, Sparkle is a "cheap" PS. It may not be sufficient for the XP 3000, (I'd use a 350 or 400) you may have already zapped it. I've seen the same thing from plugging the floppy power plug one pin off. (It's dark in there!) By the way, did the 3000 come with a "boxed" fan, or are you using the old one from the 600? XP 2000 on up run a lot hotter, you need a good CPU fan.

 

[eggbtr]

A common problem is the motherboard grounding out to the case. However this may just be the case and not the motherboard, or you may have them plugged into the wrong pins.

Sometimes a Switch on a case does not work or make contact, or is just broke, or the power or reset button is jammed in. The only way to be sure about the motherboard is to test the motherboard by removing the button wires and testing the on/off function by shorting the correct 2 pins.

There is a jumper on that board I think for 400Mhz Bus; did you set it right?

 

[Itsmillertime777]

make sure you have the power buttons on the front of the case plugged in right on the mobo i.e. pwr+ reset and hdd. check your mobo manual for how to do this. if they arent plugged in right than no power.

 

[webcats]

Micker377: I've tried the Power SW lead from the case both ways. If you are talking about the main power connection, there's only one way to connect... it's an ATX power supply. I did acutally have the floppy data cable reversed, (floppy drive light on steady) but not the power connector. I bought a brand new Thermal Take Silent Boost CPU fan, so that can't be it. I haven't yet tried pulling everything except CPU and memory, I'll try that next. Thanks.

Eggbtr: I checked the mobo grounding, I've had that problem before. It can't be the case though, I put everything into the old case I had before, and same results. I did set the jumper for 400 mhz bus. Do you think I should try it without?

Itsmillertime777: I have the manual and unless I read it wrong, I have everything plugged in correctly. I read it twice and three times, just to make sure!

Thanks for the suggestions guys!

 

[paparazi]

webcats
I think the Asus A7N8X motherboard has the extra P4 power plug connector???? so requires a PSU with this extra harness.
Sparkle actually isn't a bad make of power supply, certainly streets ahead of a cheap generic unit but 300watt is borderline for this high end CPU and if it hasn't got the extra 4pin P4 connector (thats if it needs one) you maybe advised to go 350watts+
Try reseating the main power plug to mainboard.
Also it is possible if something has been damaged in the swop that something plugged into the mainboard is preventing post ie: hard drive, CDrom or addon cards.
So try a post with the bare minimum in the system: 1 strip of memory, graphics card, CPU with cooler and PSU, don't connect front panel header connections, rather, use a small flat blade screw driver to momentarily touch the PWR header pins (this will eliminate the switch)
Did it try to start at all? the first time you tried? is the heatsink on the correct way around (recess in base positioned over the raised part of the CPU socket)? have you used some sort of heat transfer compound? paste or pad.
Reset the cmos, remove the battery or short the jumpers.
Reset the bios.
Reseat the CPU.
Martin


Replying helps further our knowledge, without comment leaves us wondering.

 

[waynrdude]

I am not sure but you possibly do not have a proper AGP X video card in. Take all cards out including the AGP and see if it will come on. You might also try an old PCI card in it just to fire it up. I have seen power supplies that are marginally or under rated not fire up because of too much load, they think they are shorted and shut off!

 

[Freestone]

The two lights on the motherboard are as follows (from the manual page 10):

"When lit, the onboard GREEN LED indicates that the system is ON, in sleep mode or in soft-off mode , not powered OFF. ... The RED LED warns if the AGP card is incorrectly installed, or is the wrong type of card for this particular motherboard."

If the red LED is on as you stated in your initial post, you have the wrong type of AGP card and have found your problem.

 

[Itsmillertime777]

makes since pop that AGP card out and see what happens. also be careful what you touch with that screwdriver if your going to jump it to turn it on. not sure what will happen if you connect the wrong things but i wouldnt wanna find out. im on a 350 watt psu from aspire and its holding up but im pretty much to the limit on voltage. go with 420 or something

 

[webcats]

Well, I found the problem. It WAS the AGP card. It is an older type, like 2x AGP. I put in an old PCI video card and it has power and I got the single beep POST ok. The problem is that the PCI card doesn't work. So now I gotta get a new AGP card. I went ahead and ordered a new power supply anyway, also. A 460 watt Enermax. Thanks for all your help and suggestions!