P4 connector on power supply doesn't match p4 on motherboard

WI_ARCH

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Jun 12, 2012
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Hello,

I just upgraded the power supply on my 7 year old Compaq Presario SR1750NX, so I could add more memory and a video card. I ordered model 630WPS power supply from ATXPowersupplies.com. to replace the original 300W power supply. The P4 connector on the power supply is keyed differently from the P4 connection on my motherboard. They both have a 2x2 orientation and are the same size, but the keying is different between the two. Surprisingly, I can still insert the power supply P4 into the slot on my motherboard, in each of the four possible positions, but the computer doesn't fire up in any of the four positions. In one of the positions the light on the front of the computer comes on for just an instant, but not long enough for the cooling fans on the power supply to even come on. The vendor is not answering it's phone or responding to my email. Is there such a thing as an adaptor available that would help me out? Or another fix?
 
Sometimes an OEM computer brand like Compaq, DELL, HP, IBM or whatever takes some liberties with the specifications in order to break compatibility with everything else on the market and force you to buy replacements only from their own company.

That could be what you are experiencing.

I don't particularly know, but it is possible.

To find out, you would probably have to find a manual for the SR1750NX and a manual for the 630WPS PSU that you have.

If you can find me those two manuals and link them here, I will look and see if I can tell if they have re-engineered something so the two things aren't compatible.
 


Standard ATX motherboard and standard ATX psu, only 1 possible position for the connector
Not your board, just an example
12v4pin.jpg
 

If the motherboard has a 8-pin ATX12V connector, it would look like three possible positions except for keying which should be preventing plugging with the wrong alignment.

With an OEM board and OEM PSU though, the keying may be non-standard and fit anywhere.
 


Follow-UP:

I finally received an email response from ATXPowersupplies.com. There is an 8-pin connector on the power supply that can be converted to two 4-pin connectors by simply sliding the two apart. One of the two connectors was keyed to match the slot on my motherboard and the power supply (and CPU) now works. So the issue has been resolved, albeit slowly.

WI_Arch