Aaah!! 2 seconds of power!!

[SanchoP]

I just changed some fan power connectors around earlier. Turned the PC on afterwards and was fine. Now I left it for about 45min and when I tried to turn it on now, everything started up but stopped after about 2 seconds...

Please advise!

 

[.Froot.]

Maybe you nudged a connector and it's become loose?
In what state is your computer after the two seconds? Off?

 

[SanchoP]

Everything is plugged in. I'm quite sure the PSU has enough juice, as it's 400w and i only have a P4, budget mobo, 3 sticks of ram, one hard drive and one optical drive and an 850xt graphics card...

What is causing this?

 

[SanchoP]

Yes, after 2 seconds it's off.

I've just made a discovery though. If I unplug the PCI-E power plug (adapted from 2 molex plugs) it's seems to run fine. And it then sounds louder, i.e. the fans are spinning faster.

Maybe I have too many things, including the graphics card plugged into too few molex plugs...

I will investigate.

 

[SanchoP]

Well it turns on for longer if the graphics card power is unplugged, but then I obviously get a warning t plug it back in. I unplugged the hard drive, optical drive and fans, so th only things going from the PSU now are mobo, CPU and VGA. Still just 2 seconds... Something up with the graphics card?

 

[SanchoP]

Well now I'm just confused. Swapped around two molex connectors, on the same cable nog al, and now it works.

 

[.Froot.]

Well now I'm just confused. Swapped around two molex connectors, on the same cable nog al, and now it works.

WTF? Strange...

 

[howardb]

What make is the 400w PSU? If it's a no-name, then that's probably part of your problem - the el-cheapies tend to have really bad voltage rails, and are often under the specified values on the sticker... do you have a spare PSU you can try?

If you have a multimeter, check the voltage on each of the molex connectors - yellow/black and red/black

 

[Gnome]

Over current protection....

PSU seems to be inadequate...

Only other option is GFX card is busted but since the system powers up very likely PSU.

 

[SanchoP]

It's a 400W iSonic...

The cable goes into a molex connector and then continues and ends in another molex connector.

Originally, when everything was running, the fans were attached at the halfway molex connector, and the graphics card was right at the end.
Then when I was shuffling the fans around, I put the fans power at the end and the graphics card in the midway molex connector. Didn't like that for some reason, so I put it back at the end...

The only reason I can think of is that the midway molex connector is slightly loose connectors causing the graphics molex to PCI-E adapter to short the system...

(The molex to PCI-E adapter user two molex plugs...)

The whole system still works fine if I only plug in one of the molex connector for the graphics card, so that's why I think the only reason (as I mentioned above) is that the dodgey connection somehow shorts something.

Both connector are connected to the same copper, so apart from the connection, there is no seal difference...