Gary Coffman wrote in message . ..

Computers all use switching power supplies, so they don't
much care if the power is clean, exactly on frequency, or
well regulated (within reason).

CRT monitors can be a different story. Some aren't regulated
very well, so line voltage variations can cause the picture
to expand or collapse, or go out of convergence. You may also
get traveling hum bars if the frequency is off. The amount of
regulation they have isn't always a function of price either.

I haven't seen a CRT monitor made since the mid-1980s that didn't
contain a fairly decent switching power supply, and I do mean the main
supply, not just the scan-derived supply. They also seem to be
tolerant of voltage down to 90V.
And since displays often don't scan at 60 Hz, monitors have to be
resistant to hum interference, and I've never seen any unless a bad
ground loop cropped up.