What was found
XPNDR CODE REPORTING ALL ZEROES ACCORDNG TO ATC REGARDLESS OF WH AT CODE IS ENTERED IN POS 1 OR 2 LOGPAGE FLAGGED FOR SDR DUE TO AIR DIVERSION TO DEN. REMOVED AND REPLACED ATC CONTROL PANEL IN REF TO AMM TO PICK UP ATC CODE ENTERED INTO PANEL (7776) NOT 0000 ON BOTH 34-53-03-000-801. PERFORMED ATC BITE. BITE CHECK GOOD. FOR SYS 1/2. NO FAULTS FOUND AT THIS TIME. PARTS USED: PRECAUTION PER RECOMMENDATION OF LOCAL TECH SUPPORT PREFORMED 29-3445-9-0004,QTY :1 ATC SYSTEM TEST WITH TR220. REF AMM 34-53-00-730-806. WAS ABLE ROTABLE PARTS CHANGE WAS INDICATED - TT # 1685905 SN OFF 2156 PANEL, ATC CONT OFF 29-3445-9-0004 2156 ON 29-3445-9-0004 2534