Do PC power supplies provide clean DC power for projects?
Scott, many people use them as a test bench supply, or for other
projects. Here's a pointer to a test bench supply:
http://academic1.bellevue.edu/robots/powerSupply/
But use google.com to search on "PC Power Supply" and testbench etc. and
you'll find lots of references.
Bottom line: You have to put some fixed load on the +5 supply, drawing 1
to 2 amps, for them to regulate properly. I like to use a 6V automotive
tail light bulb as a load and a pilot light...