OK, Here is my system:
Gigabyte MA790FXT-UD5P
AMD Phenom II x4 Black Edition 955 - Retail HSF
2x2Gb DDR3 PC-1333 Crucial Memory
Matrox MGA 450 PCI (yes, NOT PCIe) graphics card (I am trying to find a
low cost 2xDVI PCIe AMD/ATI card to replace it)
Enermax Liberty 620W PSU (24 pin + 8 pin power plugged in)
Microsoft PS2 keyboard
Kensington Expert Mouse Pro (USB)
Various hard disks, 2xIDE + 2x SATA
Nothing run above stock.
The problem:
If I plug anything other than the keyboard in to the back-panel connector, the
motherboard wont boot when first plugged into the AC power. Once the motherboard
has powered up once, I can plug in mouse/network cable and boot and run my OS
(NetBSD) happily, so long as the power supply remains connected to the mains (I can power up/down via the front panel or os OK).
My feeling is that either the M/B is faulty, or the PSU - any thoughts? (the M/B
is only a day old so far, the PSU is about 3 years old). Any way to verify
which (the PSU worked on an AMD Athlon 3200 skt 939 A8V board before - ie two
days ago)