w_tom wrote:

Brand name plug-in protector are promoted like Listerene and
Geritol. There is no such thing as a quality plug-in
protector. Take a $3 retail power strip. Add some $0.10
components. Sell it for $15 or $50 because myth brokers now
call is 'quality'. Worse still, the adjacent protector can
even complete a surge destructive path through the appliance.
Just another little fact they forget to mention.

Outlet strips won't do much and are sometimes called surge protectors.
With a surge protector, I guess you got MOVs or something else to dump
surges, inductors to show high impedence to transients, and something to
blow quickly if an MOV can't handle a surge.

With a whole-house protector, all you get is something to dump surges.
If it opens, how do you know? If it shorts, your whole house is dark.

If I had to choose how to protect a computer, I'd choose a plug-in unit,
but I've never understood whether a $50 unit is better than a $15 unit.
As you say, the components are cheap.

I have heard that plug-in-units should be replaced every year or two
because they deteriorate. I don't know if that's true. It seems to me
that a well-designed unit can be trusted until the light comes on and
you can't get power.

[...]

Yes, the linemen properly informed you of something
essential for every transistorized building. Absolutely
essential. Something missing on most all buildings.
Something so important to transistor safety that every lurker
should be now planning trips to responsible stores such as
Home Depot and Lowes. But surge protectors - the effective
'whole house' type or the scam plug-in type - will provide
nothing for this brownout or blackout problem.

When ice brought down a high-voltage line a few miles away, my
whole-house protector didn't save my TV or stereo. My scam plug-in
protector saved my computer, external drive, and modem.

Among suspects should be inspection of the circuit box. For
example, some Federal Pacific breaker boxes have been known to
burn down the building. Flickering would be a symptom of
future serious failure. The flickering may be nothing. Or it
may be symptoms of a future and major problem. In previous
posts I mentioned, in passing, the inspection of many things
such as the earthing rod. Inspection of that circuit box
(including feeling for heat on non-conductive surfaces) is
another. Immediately cannot say if those inspections would or
would not explain the strange flicker. But then even the
military demands such inspections every five years or less.

Yes, even an intermittent neutral wire does not explain your
symptoms. However this assumes just one problem. It might be
a combination of intermittents that conspired to cause that
flicker. Best we can do is inspect the usual suspects, and
'keep your ears on' for future symptoms. That strange flicker
would bother me to no end - just like the near disaster of a
Space Shuttle one full year before Challenger exploded for the
same reason. The engineers never stopped asking why and
therefore could have saved Challenger; if their management had
minds of innovators instead of bean counter mentalities.

Best to do as you are doing and to inspect those various
suspects previously recommended for inspection. Sorry I
cannot offer up a likely suspect. Best I can do is add to the
list of suspects and encourage you to keep being suspicious.

It was a gusty day, and the woman across the street from them had
flickering at the same time, after which she had to restart her computer
and reset clocks.