What was found
CREW REPORTED NR 2 BATT AMPMETER FROZE AT 32 AMPS. TROUBLESHOOTING REVEALED THE BATTERY MONITOR AMP AT FAULT. REMOVED AND REPLACED THE AMPLIFIER WITH A SERVICEABLE UNIT. PERFORMED A FUNCTIONAL TEST IAW THE MM AND ALL WAS GOOD. THE FOLLOWING DAY MAINTENANCE REMOVED AND REPLACED THE MAIN BATTERIES BECAUSE THERE WERE LOANERS ON BOARD. A BATTERY INTEGRITY CK WAS ACCOMPLISHED WITH NO DISCREPANCIES. A FUNCTIONAL TEST OF THE AMP REVEALED THE UNIT HAD FAILED. THE UNIT WAS REPLACED BY ANOTHER SERVICEABLE UNIT. FUNCTIONAL TEST WAS GOOD AND AIRCRAFT RETURNED TO SERVICE. NOTE: NO TRIPS WERE FLOWN BETWEEN THESE CHANGES. THIS IS THE SECOND UNIT THAT FAILED FOLLOWING REPAIR BY THE MANUFACTURER. (X)