P7 2*2 Connector Makes my PC Stop Running

October 31, 2012 at 09:36:24
Specs: N/A
Okay, one day, I used my PC. The next morning, I press the power button, it turns on for half a second, goes right off. Press it again, stays off. NOW, I look into my PC and notice that when I press the power button, the fan jolts a bit, but the green LED goes off...

When I unplugged the 4 pin ATX cable labeled 'P7', 2 out of 3 of my cooling fans ran, and all devices except the monitor were working!

I messed with some other plugs, and it was only that same problem.

I'm still trying to figure out what the problem is, and what is that P7 for?

I have an HP Pavilion a1240n

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October 31, 2012 at 09:42:16
I think you are referring to the auxiliary power connector for your CPU. Without that connection your computer isn't running. That is why you see nothing on the screen.

Try re-seating all the cards, cables and memory while the computer is unplugged. If no go then my guess would be the power supply has failed.

That computer is 6 or 7 years old. I wouldn't spend too much money on it. If you have a compatible power supply to try then do so.

You should be able to recover personal files from the hard drive if you don't get the computer going by removing it and connecting to another computer.

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October 31, 2012 at 09:52:07
That's the thing. It actually runs WITHOUT that cable. I can hear the regular whirring noises, my keyboard shows a connection, my mouse lights up, everything. But when it comes to the desktop, no video connection. When I actually unscrew the endsof the cord, it says 'Check Video Cable' like it was just connected. When I plug it in however, it shuts down the LED and makes the fans jolt, then stops, but acts as if it were on.

EDIT: I should also mention that I got this around 2004, but it ran smoothly all these years.

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October 31, 2012 at 10:22:18
You should NOT be messing with the connections while the computer is under power.

Where are you reading the P7 designation? On the connector at the end of the cable or somewhere else? Are the 4 pins in a row or a square pattern?
Your monitor will display a message if you turn it on without being connected to a computer at all. That is more of a self test.

A power supply has multiple rails that provide at least three main voltages. If any of them are weak or worse, the power supply is defective.

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October 31, 2012 at 10:36:51
The PC was off actually.

Printed on the side in bold letters.

Says it in the title, a 2*2

Also, I have a 20 pin connector labeled P1, and two four pin cables labeled P2 and P3 plugged in. Then there's a 4 pin P4 plugged in. P5, another 4 pin, is unplugged as well as P6, not a 4 pin. Only the P7 is 2*2, the rest are in a row.

Also a P8 which is like P6

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October 31, 2012 at 11:31:19
This P7 connectror...two yellow wires and 2 black wires?

Audares Juvo

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October 31, 2012 at 12:25:08

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October 31, 2012 at 14:22:35
Then my guess was right. That is the auxiliary power to the CPU.

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October 31, 2012 at 16:17:11
So in conclusion, I need a new PC?

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October 31, 2012 at 16:29:53
Not necessarily. You could try a different power supply. Do you know anyone that fiddles with computers? You could also try a repair shop. I wouldn't spend a lot of money on the unit.

Did you try my suggestions in #1 above?

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