On 2017-08-01, bob prohaska wrote:
>Under Preferences > Screensaver I find Xscreensaver 5.30, 11-Sept 2014.

OK, that's reasonably capable.

>DPMS (Energy Star):
>  Standby: 7200    Suspend: 7200    Off: 14400
>  DPMS is Disabled
>
>Seems like the key line is the last one, but I don't understand why the
>power manager control panel didn't do anything.

I don't work with GUI control panels, but

xset +dpms

should be a good start, and possibly reducing the timings a bit might
help.

xset dpms 300 600 1200

would put the monitor into standby after 5 minutes, suspend after 10,
off after 20.

--- SoupGate-Win32 v1.05