[SOLVED] No POST after CMOS reset

tgordine

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Oct 29, 2014
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Hi all, I'm hoping somebody might be able to help me out as I seem to be getting nowhere quick.

My existing setup was an i3-4130 on an Asus h81m PLUS and everything had been working fine, I wanted to upgrade a few things so have gotten myself an i7-4790. I removed the i3 and installed the i7, went to start up the machine, everything sounded normal, disks starting up, fans spinning etc but I was getting no display. At this point I assumed I most likely needed to update my BIOS so I removed the i7 and reinstalled the i3, went to start the machine but the same thing was happening, all the normal noises but no display.

Didn't think much of it at this point and just reset the CMOS by removing it for 5-10 mins and putting it back in but this is where all the fun started. After putting the CMOS back in absolutely nothing happens whatsoever when I press the power button, no POST, no noise, nothing.

The only things I removed in this entire process were the CPU cooler, CPU, RAM and CMOS to do the reset but just for completeness I have unplugged, checked and plugged everything on the MB but am still getting no POST. I double checked the Asus support for CMOS clear and it advises to use the CLRTC jumper as part of the CMOS reset which I have also tried but to no avail. The MB appears to be getting power as the onboard LED lights up when I plug in the power and I have checked the CMOS and it's at 2.4v.

I have tired moving the 1 4GB stick of RAM to the other slot, still no POST. I have removed all USB devices and unplugged all drives, still no POST. I have tried unplugging the power switch header and shorting it, still no POST.

If anyone has any ideas on what to do to try and resolve it would be greatly appreciated.

EDIT: Managed to get slightly further in that it will now turn on with the i7 installed but back to the no display issue, I've added full details on this below.
 
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Don't have a GPU installed so I'm just using the onboard, I've removed the CPU and checked for any bent pins but as far as I can tell it all looks good.

The PSU is a Corsair CX430.
 
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Just to update I have tested the PSU by jumping it and can confirm that the PSU fan and case fans come on. All yellow wires are 12.16v, oranges are 3.37v, reds are 5.2v, purple is 5.05v, grey is 5.2v and blue is -11.73v so all are within the 5% acceptable tolerance.
 
OK so I have gotten slightly further now, after checking the CMOS battery a few times the voltage seemed to be a bit all over the place and as I had a spare I put that in. I removed the power and restart headers. When shorting the power headers everything came back to life again, it posted fine I went into the BIOS checked a few details all looked good and after exiting it booted into Windows without any issue.

This was all with the old i3 in the system still, so I took this out again and put the i7 back in and reset the CMOS as per MB manual instructions by moving the jumper cap into the reset position for 5-10 seconds then moving it back into the default position. Started it back up by shorting the power headers but we seem to be back to the problem of no display again, everything sounds right but just getting no display once more.

When I managed to boot with the i3 I double checked the BIOS version and it was 2205 and as per the Asus website support for the 4790 on this MB was added in version 0804 so I am certain that I have the correct BIOS version for this to work now but for some reason I'm still just getting this no display issue so again would really appreciate folks help on this.
 
An update if anyone else encounters this issue although it would appear this is quite a niche problem.

After double checking the Asus website for compatibility regarding the 4790 on the H81m-PLUS MB it states that support was added from BIOS version 0804, however reading it again properly it states "Before using the new Intel 4th Gen Core processors, we suggest that you first download the BIOS updater for new Intel 4th Gen Core Processors and then update the BIOS using this tool."

With the i3 back in I managed to find the "BIOS updater for New 4th Gen Intel Core Processors" on the Asus website (it's listed under "BIOS & Firmware" just above BIOS 0804) and downloaded BIOS version 0804 just because this is the first one stated as supporting the 4790. When running the BIOS updater I then got a message stating "Please ensure that the Intel Management Engine Interface driver is properly installed before using this tool". I double checked and could see that I had a driver installed for IMEI but downloaded V11.0.0.1172 as I thought this might be a newer version from the Asus site under the "Chipset" section, tried to run it but got an error which I believe to be because this was the version I already had installed.

After a quick search I managed to find a document from Asus called "ASUS_BIOS_Update_tool_for_new_4th_Gen_Intel_Core_processors_in_8_Series_motherboards_SOP_final.pdf" and it talks about the IMEI driver being required but it mentions version 9.5.15.1730 so I found this on the Asus site, installed it and then I could run the BIOS updater and managed to install version 0804.

At this point I removed the i3, installed the i7 and now everything seems to be working fine, I can only assume that when I updated the BIOS previously to 2205 I probably did it through the BIOS itself. It would appear that to ensure this particular processor works you need to install a compatible BIOS version via this "BIOS updater for New 4th Gen Intel Core Processors" utility.