Xubuntu 16.04 monitor display no signal after turned off

This appears to be a known bug in xubuntu 16.04, see https://bugs.launchpad.net/ubuntu/+source/xfce4-settings/+bug/1575123

There have been workarounds posted on http://forums.whirlpool.net.au/archive/2529958. One is a script that I have tried (and it did work):

#!/bin/sh
#Fix TV state when HDMI link is lost.
#By Mario Limonciello <email address hidden>

OUTPUT="HDMI3"
BAD_MODE="1280x720"
GOOD_MODE="1920x1080"

for MODE in $BAD_MODE $GOOD_MODE; do
DISPLAY=:0 xrandr --output $OUTPUT --mode $MODE
sleep 2
done

The OUTPUT variable may need to be edited to suit your display. Use xrandr to find your own value for it.

Another post includes a /usr/share/X11/xorg.conf.d/*.conf file that apparently works for some. I won't quote it here because (for some reason) it froze my display.