HW-F750 soundbar hard reset

[Negativepitch]

Not sure how this has started to happen.
My Samsung F8000 series 8 tv started to turn itself off then back on again.
It also (what I thought) caused the (HW-F750 46” soundbar with valve amplifier)
to do the same which has been connected to the tv for the past three years without a problem.
I thought I would unplug the soundbar from the mains just to see what happens.
It has been unplugged for three weeks and my tv has not turned itself of once.
I have not tried re-plugging the soundbar back into the mains as yet but thought I would try a hard reset.
Does anyone know how to do a hard reset on the soundbar.
If so does it still need to be connected to the tv while it's being done.
The soundbar is connected to the tv via DIN ARC.
Thanks for any replies.