What was found
L PACK OFF/ L PACK TEMP EICAS F390, QRH LEAD TO PACK RESET AND STANDBY N POSITION, AFTER PACK RESET EICAS WENT AWAY.(<P>PLACED ON MEL 21-51-01-01 PER MDDR # 148879, CAT C, DUE: 29JUN21, MX ACTION C/W, PLACARD INSTALLED, MCC NOTIFIED. NO FAULTS ON BITE PER FIM 21-51 FT 855.</P>)