From what Tom Lear described in 060123 MMDigest, I think what he had
was an incompatibility with the fluorescent light and the UPS.  Normal
"wall power" is 120 volts, 60 Hertz, sine wave AC power.  Lower cost
USP devices output what's called "modified sine wave", which is in fact
not a sine wave output at all.  The output of one of these lower cost
units is actually square waves!  The "modified sine wave" term comes
from the way that the output waveform extremely loosely approximates
a sine wave -- sorta.

As it turns out the power supply inside a PC doesn't mind square
waves and works just fine.  However, other devices such as stereos,
TV's, and devices that contain coils and transformers (like the ballast
inside the fluorescent light) are designed to operate on sine waves.
Operating these kinds of devices on square waves will cause all kinds
of problems including unwanted spikes.  I think it was the spikes,
caused by the fluorescent light ballast operating on square waves,
which caused the damage to the computer.

The problem here was the fluorescent light being plugged into the
output of the UPS.  UPSs don't need a "boot up" time -- you should be
able to turn on the computer as soon as the UPS is turned on.  In fact,
you should really leave the UPS on all the time.  When not running the
computer the UPS takes very little energy (about as much as an electric
clock).  Leaving the UPS on will keep the batteries in the UPS charged.
There is not much point in having a UPS if it fails at the most
inopportune moment from low batteries.

If you don't like the idea of square waves going into your PC, or you
want to run something other than a PC on a UPS, there are "pure sine
wave" UPSs.  These tend to be much more expensive but, like in the
case with fluorescent light, the PC would not have been damaged.

The bottom line is this: UPSs with "modified sine wave" output are fine
as long as _only_ the PC is connected the UPS.

Ray Finch
Albuquerque, New Mexico

 [ A small fluorescent lamp for use in a motor home or RV could be
 [ connected directly to the battery of the UPS.  -- Robbie