[PLUG] monitor flashing

[Keith Lofstrom]

On Wed, Oct 15, 2014 at 12:14:37PM -0700, Denis Heidtmann wrote:
...
> at a rapid rate--maybe 10 Hz.  After a number of seconds it becomes
> steady.  
...
> Does this indicate that a complete failure is in  my near future?  A
> power supply headed for a crash?  Things to test for?

Sounds like the high voltage supply "squeeging" to me.  While you
will probably end up replacing the monitor, you have a scientific
mind, so learning cause and effect is important to your soul.

The first experiment might be switching the monitor off and on
after it has been running a while.  Do the same for the computer
with the monitor on.  Which behavior rules?

Next, try warming the monitor up (perhaps with a heat lamp,
or a few desk lamps) before turning it on.  We're starting
into the cold season, and the daily moisture and temperature
environment of the monitor has changed since summer.

I had a monitor fail this way a few years ago, during the same
season.  The explanation I came up with is that monitor power
supplies have power transistor chips bonded to a metal base
and encapsulated n plastic.  After a lot of temperature cycling,
the plastic morphs a bit and the bond between plastic and metal
develops cracks and voids.  When the power transistor is hot,
the hot air in those voids will absorb more water vapor than
the cold air around - moisture drifts into the voids in tiny
quantities.  Cycle-cycle-cycle over years pumps in nanograms
of water, which corrodes wirebonds and chip metallization.

Another explanation is that the airspaces in the monitor fill
with dust, the dust is hydroscopic, and moist dust adds too 
much electrical load to the high voltage.  So open it up and
clean it out.

Or perhaps an insect or spider crawled in there for warmth,
and its carcass is now an undesirable electrical component.
Ditto for the opening and cleaning.  

The Higher Purpose of failed electronic devices is an excuse for
us to take them apart and learn about them.  Let us know what
you find in there (besides high voltage - be careful!).

Keith

-- 
Keith Lofstrom          keithl at keithl.com