PC won't start - fans spin for half a second

MattW84

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Oct 28, 2010
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Hello everyone,

I am having a very difficult time with my PC at the moment. A few months ago I came back to my PC after leaving it on for a couple of hours to find that it had switched off and wouldn't turn on again. There was also a burning smell in the air - so something had obviously blown.

I hoped that it would only be the PSU so I bought a replacement but unfortunately there was still no power (I got half a second of fans spinning then nothingness).

So eventually I got round to buying a load of new kit, new motherboard, new cpu, new memory, etc. Werid thing is, the PC still won't turn on! I've tried all the following to no avail:

- Brought all components out of the case.
- Stripped down to just the MB and processor.
- Replaced the CMOS battery thing.
- Reset the MB BIOS using the jumpers.
- Tried different power cables.
- Checked that all power cables are connected correctly.
- Tried placing memory sticks in different sockets and removing entirely.

All this results in is the same start up issue - half a second of fans moving then nothing happens. The green light on the MB is on whenever the switch on the back of the PSU is on.

My specs are:
MB: ASUS M4A785TD-V EVO
CPU: AMD Phenom II X4 965 3.4Ghz Quad core
RAM: 4GB G-skill ripjaw
Gfx: ATI x1950 XT
PSU: Cit 750W

Any suggestions are welcome - could it be that I've replaced a bad PSU with another bad PSU (even though it was new)? Is it possible that the MB could be shorting even though it's out of the case?

I'm really at a lost end with this one and don't know what to do...
 
It happens that PSU's come DOA. Can you measure the voltages on yours?
What little information I can find on that Cit PSU of yours is that it is a low quality unit and no where close to being 750watts as rated.