HP power supply question

noobuilder1

Honorable
Mar 23, 2013
206
0
10,690
I have an older HP circa 2007 with an asus ipibl la mother board and a stock 300w psu. I got some used parts namely a older (most likely same vintage) 510w PC Power and cooling psu. I tested the 510w psu by shorting green and black wire and it comes on just fine powers some fans etc. I tried to test it on the hp and the hp will not boot or anything. Put the stock psu boots just fine. Now I noticed that the stock hp psu is a 24 pin but only has 23 wires/pins at the mobo. The pc power has all 24 the missing is a black/white stripe. Is that the reason for no boot status with the new psu or is the new psu just no good?