Pc won't turn on unless hard drive is plugged into the psu.

Vortex_Incarnate

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Mar 12, 2014
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I'm building a small cluster of Pentium 4 machines for a project and so far it's been nothing but trouble! I'm normally pretty good at fixing computers without even needing to think of asking for help but this one has got me stumped. I've already tried other psu/cpu/ram and I've taken the motherboard out of the case as well but none of that has worked.

The case is from an old Pentium 2 machine that I have stripped out and modified to fit two psu's and motherboards but I haven't gotten to installing the second board because this first has been having so many issues.

The computer will turn on IF I have a 4 pin molex plugged into a hard drive I have screwed into the floor of the case. If the hard drive is plugged into the sata port on the motherboard then it won't start, if the hard drive isn't plugged into the pus then it won't start.

It also won't start unless the hard drive is screwed into the floor of the case so this leads me to believe that it is a grounding issue, still I'm not to sure how I could check this.
 

Vortex_Incarnate

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Mar 12, 2014
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4,510
So why would you want 2 mobos and 2 psus in one case?

Conserves space over using one case per machine. I also don't want to buy a cabinet or something like that to put eight p4 boards into.

I've figured out that my issue is definitely from the power supplies and not the rest of the machine. I pulled the one from my main rig and wired it up and it worked fine, but no matter what I try to power with those other psu's they don't work. So I know now that it is definitely a grounding issue with these two power supplies. Anybody have any ideas on what to do here?