New machine won't POST

Slightly further to my previous thread here

New kit :
motherboard, cpu, ram

existing kit:
gfx card

Machine turns on (lights, fans, hdd spins up) but outputs nothing to the monitor. Tried re-seating everything and unplugging disks/ram/etc - can’t get a sausage on the screen at all.

Motherboard is one of these

Originally I wondered if the CPU was duff, so we replaced that with another one - same behaviour.

The only “weird” thing about it is, the ATX plug is 4 pins short of the socket, and when the extra 12V 4-pin square plug is plugged into the board it will NOT turn on at all. I have to unplug the 4-pin, unplug the ATX 20-pin and reseat the 20-pin before I can turn it on again.

Any thoughts at all? is it just an incompatible PSU ?

Cheers for any advice, I’m out of ideas :sigh:

okay, turns out the 12V 4-pin plug powers the CPU - so given that the board won’t power on with it plugged in, it’s no surprise it won’t POST without it :s

looks like new PSU should sort it.


New PSU time :smiley:


Glad I could help :rolleyes: :smiley: