Hello all!
I recently replaced the power supply in a Dell Optiplex 760 mini-tower PC. I found out that not any random ATX power supply will fit; the hole in the Dell case is a little smaller than is standard. You need a power supply where anything that sticks out on the back panel, like the AC line connector, isn't too close to the edge of the power supply. I couldn't make an Antec Basiq 350 fit - its line connector was too close to the edge. An Antec VP450 fit and worked OK.
I made a small writeup about it:
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Also note this is *not* one of the "small case" versions of the Optiplex
760; those take a non-ATX supply that I don't know much about.
Standard disclaimers apply: I don't get money or other consideration from any companies mentioned.
I hope this helps!
Matt Roberds