display blinks on and off when not on charger

[jpaulbiss]

You were correct; software related. I flashed Mobian to a SD card and it works with out being plugged in.   Now to find an OS that has the apps I use, which isn't many. Signal, Wire, the difficult one to find outside of Android is the ones for online banking.
Thanks

Glad to hear it works! For Signal your best bet is probably Axolotl which has been packaged already for Mobian (not in the repos though I think) and Manjaro/Arch (AUR, repackaged from the Mobian version), although it doesn't work properly at the moment due to changes on Signal's side. Banks use their proprietary apps I guess which will most likely not be available for Linux, but maybe you could get it to work with Anbox.

Thanks
Mystery solved.

Just a follow up... I flashed the latest vers of the OS using jumpstart and  balenaEtcher, the issue dissapeared. updating the software alone has no effect. Thanks everyone for the help and I apologise for being such a grunpy old fart.