APC UPS Model PR550i Repaired
The complaint for this APC UPS Model PR550i was it can’t charge and sometimes (intermittently) all the front panel LED’S lights up. A new battery was replaced with no improvement. Since the problem have some similarity with some other models then the problem could be a corrupted EEPROM DATA. In order to confirm this problem, a similar working UPS EEProm IC was taken and placed it to the faulty UPS. The result was, it start to work normally! Since we have know that the data had been corrupted so the Pony prog eeprom Programmer was used.
First , save the good eeprom data file into the hard disk and then over write the corrupted IC with the good data. For your information, eeprom IC rarely have problem, most of them the problem was only the data corrupted. Once reprogrammed, it will work as good as a new IC! By the way the EEPROM IC part number is 93C46 SMD type as seen from the photo below together with the Pony Prog eeprom programmer.