> That said, if it turns out that you *do* need to replace the
> UPS, secondhand
> APC SmartUPSes can be had pretty cheaply on the secondhand
> market.
I've now had two APC UPSes in a row fail the same way. Battery is good (and a
new battery does not solve the problem). Unit passes
self test every time. But when the power fails, they act exactly like what MJB
described. Run about 10-15 seconds and quit.
Best I can make out, the failure is in the battery sensing circuit. Output
transistors seem OK, and the inverter will keep running
for several minutes with a very light load (like a 60 watt light bulb).
Nothing seems to get abnormally hot.
First time I figured it was a random failure, but now one of the ones under my
desk at work has developed the exact same symptoms.
Fortunately I've not been running any long-term tests recently, so it really
doesn't matter.
Randall
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