Stable new build - now no POST or video out! All guides worked through!

adventg

Commendable
Feb 24, 2016
4
0
1,510
Evening all!

Never posted on here before! (but I have read your sticky about no video, fear not!)

I just built a new 3D CAD workstation for my employer (not my first build!), which upon first breadboard build would only intermittently POST and boot, sometimes working fine - sometimes no video output. Would have to reset a few times to get video output.

Had an warning about PSU surge, and that the board had activated Asus protection etc etc. Tested with a known good PSU instead - no difference.

In the end, it deteriorated to the point I ended up with no ability to boot at all - and returned the mobo for an immediate replacement. So, rebuilt with the new board - similar problem, intermittent POST and boot - BUT, once up and running - no problem, Windows installed fine from DVD (other than some challenges because of intermittent ability to boot), and all up and running.

Ran 3 hours (EDIT - actually, probably more like 2) of Prime95 on all 8 threads today, and about an hour of Furmark - no errors at all. Windows memtest also reports no errors.

Spec is as follows;

i7-6700 w/ stock cooler
Asus H170M Plus mobo
CX430M PSU
Samsung SM951 M.2 SSD (AHCI version) as C drive
Kingston SSD Now SSD as data drive
NVIDIA Quadro K620 GPU
16GB of Corsair Vengeance LPX DDR4
Win 7 64bit

So, here comes the big problem - I've been using the machine all day for taxing, heavy 3D CAD tasks (and those stress tests), installed large applications etc - no problems, entirely stable as far as I can tell.

Decided this evening to update the BIOS from USB (using Asus EZ Flash in BIOS, not from Windows) to see if that would resolve the intermittent booting issue. I saw the progress bar get to 100%, followed by the screen go black - and I haven't been able to boot since!

I'm afraid I can't seem to find my system speaker right now, so can't listen for any POST codes or anything! I've removed the GPU and am connected to the mobo VGA port instead now, no different.

Disconnected all peripherals etc!

Wondering if anybody has any input here, as I currently have a bricked machine! I've tried reflashing the BIOS with the recovery tool, Asus CrashFree method - no luck.

Also reset the CMOS by shorting the clear jumper, and by removing the battery and shorting the jumper. No joy...

EDIT - I can't swap the RAM out of my personal build, as it's DDR3L, not DDR4 - and I don't fancy putting my CPU in the troublesome machine right now... I don't need two dead machines!
 

garyshows

Reputable
Aug 29, 2015
531
0
5,160


it might be the psu cx series power supplies are cheap made and low qauility
 

adventg

Commendable
Feb 24, 2016
4
0
1,510
Have just tried with a known good PSU - and exactly the same thing. No POST at all.

So, tonight - I'm going to take the i7 out of this new build and try it in my home office PC tonight; if that works - then I suppose it isolates it down to two things;

- bad memory (but if this was the case, I'd get POST codes indicating no memory, and it wouldn't have run stable under full load and worked all day yesterday
- or, bad PSU that has killed a second board?

Any thoughts anybody?

EDIT - or, bad BIOS update that has bricked the board. The board has a socketed DIP8 flash chip for the BIOS, so I've got a ticket in to Asus to see if I can get a replacement chip with a good BIOS flash on, as a backup!