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I bought a new power supply but I'm not sure if it's broken

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May 12, 2009 3:20:38 AM

My OS is windows vista home premium on an AMD athlon 64 X2 dual core processor 3800+ with 1gb of ram and a nvidia geforce 6150se nforce 430 graphics card. The model ID is SR5130NX and it's made by compaq. The motherboard is M2N68-LA. The old power supply it came with is made by Bestec, model atx-250-12z rev: D3R
Basically it's the sr5130nx model with all of the standard parts.
I wanted to upgrade some of the equipment in it so I decided to change the power supply to one with more wattage to handle the new equipment, but after switching out the old power supply for the new one the computer would turn on and the power supply was running, as was its cooling fan and the cooling fan on my cpu. I was able to open and close the cd-rom drive as well, but the problem is that the keyboard and monitor and my external hard drive showed no signs of communication with the computer whatsoever. The monitor stayed as if it were not connected to the comptuer at all, the external hard drive did not light up, and the keyboard made no response and I couldn't turn on the num lock light or the caps lock light. After putting the old power supply back into the computer it worked fine again.
Where did I go wrong? is the power supply broken? could it be that the newer power supply is simply noncompatible with my older computer in some way? did I simply connect the cables wrong somehow?
Here is a link to the new power supply I wanted to use http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Here is a link to the old power supply for my computer
http://www.censuspc.com/Bestec--ATX-250-12Z-Rev-S--250-...
Keep in mind that I hadn't installed any other new hardware besides the power supply.
I should also mention that I have a wireless card installed in the back of my computer above the graphics card and it still lights up.
a c 144 ) Power supply
May 12, 2009 2:20:28 PM

Assuming you hooked it up correctly, with the two motherboardf connectors properly seated, if it doesn't work, it's clearly defective.

And the rest of the symptoms: because the fans run, the 12 volt output is probably good. And the wireless card is probably powered by the strandby power supply. That's a small, separate power supply providing the "+5VSB" output you see in the specifications.

You should get a better, not just more powerful PSU - like Corsair, Seasonic, PC Poer & Cooling, or Antec.
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May 13, 2009 7:10:34 AM

^Agree with jsc's choices of PSU brands. Would prefer you go with Corsair though.
a c 105 ) Power supply
May 13, 2009 4:17:52 PM

Even though it was in a Compaq, was there a necessary "Dell proprietary" connector on the Bestec that is missing from the new one, or was that Bestec link actually not to the identical unit?
May 16, 2009 6:16:15 AM

Ok, so, after doing some digging around and according to some other guy in a different thread, my computer's old power supply, atx-250-12z rev: D3R, should NOT be proprietary and should be a regular ATX power supply, as you can read here: http://forums11.itrc.hp.com/service/forums/bizsupport/q...

Can anyone verify this? also this means that something else must be preventing my new power supply from working properly with the rest of my computer. Any ideas? I've got all the cables hooked up right, and looking at the color coding for the connectors, all of the same color cables go to the same places on both power supplies. Not that colors necessarily mean everything is the same volts/amps but its something anyway.



Any ideas on what I should try to get it to work?
May 18, 2009 2:34:32 AM

The only suggestion I have left is that you try your new power supply with another computer, so that we can eliminate it as a cause.
a c 144 ) Power supply
May 18, 2009 12:34:14 PM

If you have a multimeter, you can check all the outputs. Yellow wires should be 12 volts, red 5 volts, orange 3.3 volts, blue wire -12 volts, purple wire is the 5 volt standby. The tolerances should be +/- 5%. If not, the PSU is bad.

The gray wire is really important. It sends a control signal called something like "PowerOK" from the PSU to the motherboard. It should go from 0 volts to about 5 volts within a half second of pressing the case power switch. If you do not have this signal, your computer will not boot.

These voltages can be monitored on the back of the main power connector. Be careful. You will be monitoring live circuits. The voltages are low enough that there's no danger of shock, but an accidental short could destroy components.
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