P8ZZ7-M help flashing green led

[Betts1]

Hi hoping somebody can help ive just finished building a htpc using a Asus P8Z77-M With a i5 3570k in a Antec Fusion case.

Installed everything but the system won't power on no fans move etc. I've noticed a green light flashing on the motherboard also the antec LCD screen comes on but flashes on and off almost in sync with the light on the motherboard. I've tried booting with just the CPU & psu connected to the motherboard but still the flashing green light.

Can somebody help??

 

[C12Friedman]

Welcome to Tom's Hardware Forums,
Your motherboard has two led's, one near the ram banks, and one near the PCI slot. Which one is blinking? Doesn't matter, I'm going to direct you here for troubleshooting tips
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems
Hope you get it figured

 

[Betts1]

Thanks for replying the led that's flashing is the one near the pci slot it says sb_pwr

 

[C12Friedman]

both power cables (24 pin and 8 pin) are connected to the motherboard?

 

[Betts1]

24 pin yes my other cable is only a 4 pin could this be the problem I'm using the antec earthwatts psu I got with the case

 

[C12Friedman]

It shouldn't be a problem in itself, the Antec is a decent PSU. You could try putting the 4 pin on the other side of the connector (unless there's a sticker on it saying use the other side).

 

[ram1009]

Have you tried using the ASUS manual?

 

[Betts1]

I've read the manual it doesn't mention anything about flashing green led's

I'm just trying another psu

 

[smorizio]

sounds like you have a dead power supply or something is shorting the power supply out. check that the mb standoff were used and no part of the mb is touching the case. take the video card out if your using one and use one stick of ram and see if it posts. if your getting the same issues try another power supply. per asus web page the mb should post with the stock 802 bios that comes with the mb.

 

[Betts1]

Right just changed psu to a Corsair cx 430 i havent connected everything just the cpu & psu and the light is now constant green.I think i've found the problem

 

[C12Friedman]

Yep, that would seem to be it. BTW, I read the manual also just to see if there were any intricacies that may have been easily missed.

 

[C12Friedman]

Since this is a new build (new case and PSU assumed). I would be in contact with Antec about getting the PSU replaced.

 

[Betts1]

It was a second hand case which is in mint condition.Ok so i've just tried the paperclip test and the fan on the psu is working fine ???? Could it be the 4pin Connection needs to be 8 pin?

 

[C12Friedman]

A motherboard which can use the 8 pin will also run with only a 4 pin so that shouldn't be the issue. I would be concerned about the Antec PSU, the paperclip "test" simply verifies that it powers on, doesn't tell you anything about the usability of the PSU - any of the rails can be way out of spec, it will still power on. You can check to make sure none of the connectors have loose wires - i would not be surprised to find one (or more) loose on the 4 pin connector. If you have access to a Digital Multi-meter (or know someone with one), you can jump the PSU and then test the individual voltages - that'll let you know for sure if the PSU itself has issues.