GA-MA74GM-S2H May it have a short-circuit?

[Derek1]

I have bough a MA-74GM-S2H and I built it with

CPU: AMD Athlon 64 X2 3800+
Mainboard: Gigabyte GA-MA74GM-S2
Memory: 2 GB Kingston
Hard Drive: Seagate Barracuda IV 40 GB
Video: (Onboard) ATI Radeon 2100
Sound: (Onboard) Realtek ALC 888
CD Rom: TSSTCorp writemaster
Power Supply: Colorsit 500 W

But it doesn't want to start, it does nothing, no fans spin, no leds light...
Then I connected the keyboard (PS/2) and mouse (USB) and I noticed that the lights in both peripherals are blinking constantly and the PSU emits a faint clock-like noise "syncing" with the blinking lights
Finally I researched a bit and I found that my PSU +5VSB line (2.5A MAX) may be protecting itself from a short-circuit or overload.
I tried to put the board out of the tower case but nothing
I tried to disconnect all hardware but nothing.
My PSU works fine with another board.
No smoke or burning smell.
No visible short-circuits.
I returned this motherboard and got the same model: same issue
I'm astonished. What would cause my problem? May be a flaky +5VSB line?
Many thanks.

[artdrivers]

It does not matter if you did this before. The first thing I would do is not install it until you get a P.O.S.T. Bench test out of the case and off chassies for P.O.S.T. You could be getting a short from the case. We recommend removing that motherboard from the case/chassis and test the board for POST. Please follow the following simple steps.
1. Place the motherboard on top of the cardboard box (you can use the motherboard box)
2. reseat and or install a good CPU, good CPU fan, good Memory, good power supply (plug the 1 X 20 pin and 1 X 4 or 2 X 8 pin from the power supply unit) and a good video card.
3. Hook the monitor to the video card and be sure the monitor is switched on.
4. Turn on the system board by using the good case "Power on" switch.
If the system fails to POST, check the components' insertion again to ensure they are all connected properly. Try to refrain from adding any drives or usb connections or other parts that may cause a failed P.O.S.T.!
These are instructions from Gigabyte. Try this and let us know how it goes. If no P.O.S.T. try this while it's out. Have you reset the bios? Have you tried checking that board with a different power supply or Graphics card or memory or cpu? Perform a thorough inspection on all the parts. If you try all of the above and no P.O.S.T. Then you may want to RMA the board.

[Derek1]

Hi. Many thanks
I've done yor instructions (except video card, I use the onboard one), and nothing, the system is competely dead, no signs of life except the blinking lights commented!. The CPU and memory are OK (work in another board)
What is strange, I RMA it and they gave me other one---> same problem
What I will try today is to get another PSU, maybe the mine is faulty and this board requires more power or anything...

[VorLonUK]

Your setup in terms of current demand is in the low/mid bracket when compared to other setups we see on here.

But when I saw:- Power Supply: Colorsit 500 W, i didn't want to look any further! Put it this way, you'd could get 350watt PSU's from other manufacturers that would out perform the one you have.

If it is definately causing the problem is another matter, but short of measuring the voltages whilst the board is starting up (or attempting too) I'd dump the Colorsit for another make of PSU (ie one from the high end/enthusiast market)