Help, cant pin down problem

Kalearne · 27 Jan 2013 at 16:59

Ok I've got a problem and needing some help trying to diagnose so I hope you guys n gals can offer some advice.
Heres the rigs specs;
Mobo: ASUS M4A7B-E
Chip: Not sure
Memory: 16GB GSkill F2-6400CL4D (4GB x 4)
GFX: ATI Radeon HD 48901
HDD: 2 x 500GB Hitachi Deskstar
PSU: Toughpower 750W

Heres the problem;
It wont even POST. PSU appears to come on, lights n fans power up, HDD's power up. No signal from the machine and no beeps from the onboard speaker.
Heres the single interesting diagnostic point. When you try and turn the power off via ATX power switch it fails to respond. You HAVE to toggle its power from the back.

Current progress
Id initially got the rig with reports that 'I think the gfx card is broken' so I started to strip it down and test the parts individually in my rig.

Memory and GFX card test and work fine.

At this point I pretty much assumed it was a faulty PSU and told my friend to check out Overclockers. He purchased a rather nice OCZ ZX 850W which I rewired into his rig.

The problem persists, right down to the ATX refusing to power off from its front switch.

I then stripped his rig down to the following components;
Mobo
PSU (OCZ)
GFX
It still failed to get to POST.

Any options or advice? :confused:

Kalearne · 27 Jan 2013 at 21:49

Yeah I made sure the 12v rail is in.

Yes it was overclocked previously (but had since lost its settings and had been happily running standard settings)

I havent as yet flashed the CMOS

(im assured the rig hasnt suffered any knocks, no flashes or bangs.. one day it just wouldnt boot)

Kalearne · 27 Jan 2013 at 23:43

trickynickyuk said:
try resetting the Cmos and see what happens could be your PSU as well

Already replaced PSU and problem persists.. Will check clearing CMOS tomorrow.

Kalearne · 4 Feb 2013 at 08:36

Tried clearing CMOS and as feared no change.. looks like I'm advising a new mobo.. Damn I was hoping for something easier. Thanks guys, your advice was much appreciated.

Kalearne · 4 Feb 2013 at 08:40

Thanks Chris, 24 pin only and no beep.

Kalearne · 4 Feb 2013 at 08:44

I originally thought it was a faulty PSU so I already got my friend to buy a replacement OCZ 850. So yes we have spare PSU, no it didnt change anything.

Also I can see the PC speaker plugged into the mobo but it aint beeping or anything.

Kalearne · 4 Feb 2013 at 08:48

Thanks skyline.. when I said I can see the speaker I meant I can see a small PC speaker thats plugged into the area where the reset/pwr/led etc go. Its hanging free but it is a cheapy piezo speaker.

Ive already stripped the machine down to the components you mentioned to try and limit whats broken.

So yeah, looks like the mobo.

[EDIT] So I guess next question is whats a good replacement mobo? (guy thinks his chip is a quad core phenom II)