Dear Support Team, We have a problem in our AB PLC 5/60 Enhanced device(1785-L60B/E), it is a redundant AB PLC system and controlling a Water RO plant. Another paralleled connected system is working fine. 1. Once power went down and power up, the PLC started showing "PROC" error- Steady RED. Loaded the program from EEPROM, the PLC "PROC" error is gone but the DH Channel A RED LED is started Flashing. 2. After loading the program, the program vanishes automatically even when there is a power, and again showing "PROC " Error - Steady RED. Changed new Battery. 3. Looking for the replacement processor, found same series and part number but the Firmware and REV is different. Advise the selection of suitable replacement. 4. The PLC program is password locked. Any solutions or work around to solve the issue.