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 says66-0546. 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.
When plugged in to AC, the unit has its green LED lit which shows it is getting AC power in. The yellow LED flashes. according to the manual, "This yellow light will turn ON continuously to indicate that the UPS's battery is less than fully charged. If it stays on continuously, contact Tripp-Lite fo service. The light will flash after you set the 'OFF/ON' Switch to the 'OFF' position to indicate that the UPS will not provide battery backup during a blackout or brownout." Regardless of whether I set the OFF/ON switch to OFF or ON, the yellow light flashes.
There is a Mute/Test switch. If I run the test, the red LED briefly lights and the alram briefly sounds, as if it tried to switch over to battery power but there was no power there.
It kind of seems like the charging circuit is not charging the batteries but I don't know how to test this theory. I left it sit plugged in for a few days hoping it would charge but it did not.
There are several fuses on the circuit board, all soldered on, and they all measure zero ohms so I don't think that is the problem. There are no obviously leaky capacitors or any other components that look burned up or damaged judging by visual inspection.
I like this UPS and would like to revive it, especially since I spent money on the new batteries. If anybody could help me diagnose the problem, tell me where to start, what to check, etc. I would appreciate it.
All ideas welcome. Thanks in advance.