Question Asus P8Z77-V PRO green lights on but nothing starts

[wheretheresawill]

Hi I have this mobo -
Asus P8Z77-V PRO Thunderbolt

I just connected this PSU -
Corsair TX750 750W ATX Power Supply

When I turn on the PSU the MOBO shows 2 green lights. Here's a pic -

When I try to turn on the MOBO via the case power supply nothing happens.

I've tried to clear the CMOS moving the reset pin but nothing changed.

I've removed the RAM sticks and tried a power drain. Still nothing.

What else can I try to get it the CPU fan and HDDs working?

Thanks for any help

 

[Darkbreeze]

So, disconnect the wires coming from the case front panel power switch and try to power on the system using this method.

https://www.gamersnexus.net/guides/2011-jumping-a-motherboard-without-power-switch-button

And if that too fails to power on the board then you should double check everything listed here:

"No POST", "system won't boot", and "no video output" troubleshooting checklist

"No POST", "system won't boot", and "no video output" troubleshooting checklist This checklist is a compilation of troubleshooting ideas from many forum members. It's very important to actually perform every step in the checklist if you want to effectively troubleshoot your problem. 1.Did you...

forums.tomshardware.com

and if that offers no insights then you can benchtest the board:

How To - Motherboard bench testing

Finding the problem through bench testing If you are here then it’s likely you have encountered a serious hardware issue and have been unable to resolve it using the standard no-POST troubleshooting procedures. If you have not yet attempted to resolve your issues using the no-POST...

forums.tomshardware.com

But by that point it's pretty likely that it is simply a failed motherboard which wouldn't be very surprising considering that's a 10 year old motherboard and most motherboards are lucky if they see 5-7 years of fairly regular usage.

 

[wheretheresawill]

So, disconnect the wires coming from the case front panel power switch and try to power on the system using this method.
https://www.gamersnexus.net/guides/2011-jumping-a-motherboard-without-power-switch-button

I tried to jump the board but no response.

I removed the case front panel switch and touched the power switch with a screw driver. I'm pretty sure I did it right, highlighted from the manual -

Thanks for the quick reply

 

[Darkbreeze]

Yeah, if you get nothing by doing that then either you don't have both the EPS/CPU 4+4 pin power connector and 24 pin ATX connector plugged in, or not fully plugged in, or the board is dead. Because even if you had a bad CPU, or graphics card, or memory, it should still at least power on.

Also, you might need to reset the PSU, which involves flipping the switch off on the back of the power supply, unplugging it from the wall, allow it to set for about five minutes (Might not hurt to also remove the CMOS battery at this time to reset the BIOS as well and then after five minutes reinsert it before moving on) and then plug it back in and flip the switch back on, then try to power on to see if perhaps it was a PSU protection that was stopping it. If that doesn't help, you can always try unplugging all drives, remove the graphics card (IF there is one installed, which it doesn't look like there is), leave just one stick of RAM installed in the second slot over from the CPU socket (A2 slot is the designation on most boards) and try to power on with minimal hardware to see if perhaps one of those devices was triggering protections.

If not, then likely it's the board.

Out of curiosity, what is the model of the CPU that is installed?

Was this system running previously or is this hardware new to you and first time trying to get it running?

 

[wheretheresawill]

Yeah, if you get nothing by doing that then either you don't have both the EPS/CPU 4+4 pin power connector and 24 pin ATX connector plugged in, or not fully plugged in, or the board is dead. Because even if you had a bad CPU, or graphics card, or memory, it should still at least power on.

Also, you might need to reset the PSU, which involves flipping the switch off on the back of the power supply, unplugging it from the wall, allow it to set for about five minutes (Might not hurt to also remove the CMOS battery at this time to reset the BIOS as well and then after five minutes reinsert it before moving on) and then plug it back in and flip the switch back on, then try to power on to see if perhaps it was a PSU protection that was stopping it. If that doesn't help, you can always try unplugging all drives, remove the graphics card (IF there is one installed, which it doesn't look like there is), leave just one stick of RAM installed in the second slot over from the CPU socket (A2 slot is the designation on most boards) and try to power on with minimal hardware to see if perhaps one of those devices was triggering protections.

If not, then likely it's the board.

Out of curiosity, what is the model of the CPU that is installed?

Was this system running previously or is this hardware new to you and first time trying to get it running?

I bought a new PSU because the old PSU stopped working after I tried connecting a USB behind the case without looking. I was guessing where to put the USB and after that the PSU wouldn't turn the MOBO on again. There was no green light on the MOBO when the old PSU was connected.

I think there is some hope it still works because the MOBO has a green light now?

I haven't tried taking out the CMOS battery yet. I will try that next.

Thanks for the help. I will report back asap.

 

[Darkbreeze]

So, if you fried the PSU by plugging a USB connector into something it wasn't supposed to be plugged into, then it is HIGHLY probable that you cooked the board as well. It would be almost impossible to cook the PSU and not cook the board too in that situation.

But, there is always the chance that you simply turned the switch on the PSU off while reaching behind it. Did you CHECK to see that the switch on the PSU wasn't flipped to the off "0" position instead of the on "I" position before replacing the PSU?

 

[wheretheresawill]

So, if you fried the PSU by plugging a USB connector into something it wasn't supposed to be plugged into, then it is HIGHLY probable that you cooked the board as well. It would be almost impossible to cook the PSU and not cook the board too in that situation.

But, there is always the chance that you simply turned the switch on the PSU off while reaching behind it. Did you CHECK to see that the switch on the PSU wasn't flipped to the off "0" position instead of the on "I" position before replacing the PSU?

Hi @Darkbreeze,

Great news it's working again!

I got lucky. I was about to give up. I tried the 6pin in the 8 pin and that managed to power it up!

My GPU (GeForce ZOTAC 1070) is now playing up. When I plug it in the GPU fans start and stop. The display worked but then blacked out. I might just have to use the onboard GPU.

Thanks for all your help!

 

[Darkbreeze]

Sure thing.