I use my HD Plex PSU for my uRendu, and a DIY PC in a HD Plex box. I did hook up my multimeter as I adjusted the adjustable output for the uRendu. Comments in some of the forums recommend 7v if possible. Actually the adjustable output on my box has a minimum output of 7.5v, which was verified by my multimeter. Works great.
Now if I can figure out why the PC turned off, and wont turn on... (I am currently building and amp, and using my NAS as the Roon server, so fixing the PC is not on the front burner)