What was found
(CAN) WHILE CONNECTED TO A GPU, DURING ROUTINE MAINTENANCE, THE TECHNICIANS NOTED SMOKE IN THE AREA OF THE BATTERY BOX COMPARTMENT. THE GPU WAS IMMEDIATELY DISCONNECTED, BATTERY POWER TURNED OFF AND THE BATTERY DISCONNECTED FROM THE AIRCRAFT BY REMOVAL OF THE ALCON CONNECTOR AT THE BATTERY. THE BATTERY HAD OVERHEATED AND WENT INTO A THERMAL RUNAWAY CONDITION. THE BATTERY WAS REPLACED AS WELL AND THE BATTERY CHARGE MONITORING PRINTED CIRCUIT CARD. (TC NR 20061128008)