On Thu, 8 Apr 2021 17:32:30 +0200, Antony wrote in message
<202104081732.30426.Antony.Stone@???>:

> On Thursday 08 April 2021 at 17:26:42, Bernard Rosset via Dng wrote:
>
> > >> I would boot from an installation USB / CD (preferably the one
> > >> you set the
> > >> machine up from) and go into Rescue Mode, and see whether the
> > >> hardware still
> > >> continues behaving the same way.
> > >
> > > I just did that on the latest Devuan Beowulf Live distro (kernel
> > > 4.19.0-14), and... no flickering!
> >
> > Booting back on the internal disk... No flickering.
> > I just don't get it. Would it be hardware/cable-related in the end?
> > *sighs*
>
> I would say yes, it sounds like a dodgy cable / solder joint /
> connector to me.

..it could quite simply be dust collected inside your machine causing
overheating triggering hardware trottling to near your power grid
frequency, e.g. down from say 60Hz in a 50Hz country like France, to
say 42Hz, which mould have your screen flicker at say 8Hz.

..fix is easy in this case, open your machine and clean it out with
e.g. pressurized air in a well ventilated area.

--
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
Scenarios always come in sets of three:
best case, worst case, and just in case.