Hello YC,

I ran across this article you posted on a CyberPower 500sl and I think
I can help, primarily because I work for CyberPower Systems. The unit
may have behaved this way due to the fluctuation in the AC power. In
most instances, the power will surge or spike after a momentary power
blip. As the power stabilizes on the power grid, the voltage is eratic
and the CyberPower UPS is designed to filter this "dirty power" and
absorb the inconsistencies. This is why it is crucial to have a
CyberPower UPS on your computer equipment.

This model actually has a 3 year manufacturers warranty. Most of our
competitors have 2 year warranty's. I invite you to contact our
award-winning tech support at 1-877-297-6937 or via our website at
www.cyberpowersystems.com and we'll assist you in any way we can.

Ryan T. Jessen
VAR Sales Account Manager
CyberPower Systems, Inc.

CyberPower - "The Power to Control the Power"









Young Coot wrote:
Hello -

glad this newsgroup is he I wanted to compare notes to see if
anyone else
has dealt with this situation.

I've had a CyberPower 500SL UPS for about two years, and it behaved
perfectly well while under the manufacturer's 2-year warranty.
Yesterday,
during a momentary power dip, the unit did its job and switched to
battery
power, but never switched back after the voltage returned to normal.
It
behaved as though the power had gone out altogether, buzzing and
beeping,
and the software on the computer counting down the five minutes until

shutdown. I checked the circuit breaker down the hall, all was fine,
and
every other electrical appliance in the house had electricity. So I
took
the unit out of service and tested it all around the house. No
matter what
outlet it was in, it would respond as though it was not plugged in at
all.
The battery backup was doing its job perfectly.

I had the top off and the battery out, testing the unit in various
ways (all
inner components seemed to be fine). It beeped with the battery out
as
well as the battery in. The testing ended when I put the battery
back in,
turned the unit on, and two seconds later one of the transistors (a
STP55NE0, a 60-volt 55-amp MOSFET probably serving as one of the
voltage
regulators) burst with a brief flame and cracked down the middle.
Good
thing it wasn't in service when this happened!

I'm doing salvage and forensics on it now, since UPS units are
cheaper now
than they were two years ago and I can get a fresh one very easily.
I'm
figuring it was one of the logic chips that controls the switching
that
went bonkers, and wound up putting two voltage sources across the
same
transistor simultaneously.

Anyone else have a similar experience?

YC