What was found
DURING STAR CHECK FOUND LOWER ECAM BLANK SCREEN WITH -F DISPLAYED. PEFORMED DMC SYSTEM BITE TEST REF TASK 31-60-00-740-004-A, FOUND FAULT CODE DU SD(4 WT2). FOR TROUBLESHOOTING PURPOSE, SWAPPED UPPER ECAM TO LOWER ECAM ANDFAULT.FOLLOWED. SWAPPED LOWER ECAM BACK TO ORIGINAL SPOT. DU 4WT2 NIS IAD REQUESTING MEL. PARTS ADDED NOC.OK TO DEFER LOWER ECAM DU ON MEL DDP FOLLOWED REPLACED LOWER DU. UNABLE TO CLEAR, NO DATA FOUND. REMOVED PART , MFG S/N: C19755056882. MFG P/N: C19755BA01, M&E S/N: 6882. REPLACED LOWER DU IAW AMM 31-63-22-400-001-A. OPS CHECK GOOD.