On Sat, 19 Feb 2011 12:56:57 -0800 (PST), martinmarty
wrote:

I have a UPS about 11 years old. It is an IBM OfficePro 700 which is
actually a Tripp-Lite product. Inside on the circuit board it says
66-0546. The web says the Mfr model number is 10K1912.

Not too long ago its yellow light started flashing that says the
batteries are discharged. Because of its age, I assumed the batteries
were worn out so I bought new ones. Unfortunately, after installing
them the problem did not go away.

I know it's no consolation (or help with your problem now) but any
time a cheap (i.e."desktop/office") UPS shows symptoms of failure the
battery system is the culprit 95% of the time, or more.

When it IS a genuine UPS fault, it is almost always beter to junk it
and buy a new one.

The only way you can tell which is the fault is to jury-rig another
battery to the UPS and see if the symptoms continue. Fortunately most
of this category of UPS use 12V so a spare auto battery will suffice.

(I have a bank of four 12V 100Ah SLA's which I am routinely using to
verify the functionality of assorted UPS' brought here, up to ~6kVA.)