dell - Kubuntu - Screen Goes Blank After 31 Seconds Of Not Moving Mouse - Ask Ubuntu

i'm novice @ linux/ubuntu. installed kubuntu , have configured power management , display , monitor settings appropriately. i've installed caffeine, , have tried multiple times prevent screen going blank. i've followed other articles , tried disabling screen blanking feature. i've disabled power saving options.

issue: after 31 seconds of not moving mouse, if multimedia - including web-based multimedia - still playing, screen goes blank. please give me specific instructions when referring terminal commands , respective directories.

thank in advance.

troubleshooting performed: mv ~/.kde ~/.kde.old mv ~/.cache ~/.cache.old mv ~/.local ~/.local.old mv ~/.config ~/.config.old shutdown -r disabled hardware acceleration in firefox , chromium rm ~/.local/share/kscreen sudo killall sddm tried new sessions

xset -q revealed following: xset -q keyboard control:
auto repeat: on key click percent: 0 led mask: 00000000
xkb indicators:
00: caps lock: off 01: num lock: off 02: scroll lock: off 03: compose: off 04: kana: off 05: sleep: off 06: suspend: off 07: mute: off 08: misc: off 09: mail: off 10: charging: off 11: shift lock: off 12: group 2: off 13: mouse keys: off
auto repeat delay: 600 repeat rate: 25
auto repeating keys: 00ffffffdffffbbf
fadfffefffedffff
9fffffffffffffff
fff7ffffffffffff
bell percent: 50 bell pitch: 400 bell duration: 100
pointer control:
acceleration: 20/10 threshold: 4
screen saver:
prefer blanking: yes allow exposures: yes
timeout: 0 cycle: 600
colors:
default colormap: 0x20 blackpixel: 0x0 whitepixel: 0xffffff
font path:
/usr/share/fonts/x11/misc,/usr/share/fonts/x11/type1,built-ins
dpms (energy star):
standby: 0 suspend: 0 off: 0
dpms disabled

some specs: kubuntu 16.10 kde plasma version 5.7.5 kde frameworks version 5.26.0 qt version 5.6.1 kernel version 4.8.0-27-generic os type 64-bit dell latitude e5410