[wlug] Linux Mint "Uma and Vera"idle problem..

Hi Folks, My installation of Linux mint Vera 21.1  has a very annoying habit of going into "idle" mode after 10 minutes. Makes watching a movie or listening to music a less than enjoyable task. I have on past installations of Mint sought answers, including running a couple of lengthy bash scripts I found in the forums to no avail. AFAIK my screensaver and power management setting are OK. the problem seems widespread through all the applications I have tried so far Rythmbox Celluloid VLC and Netflix Any help will be appreciated.. Cheers John..